Gene Vogel
EASA Pump and Vibration Specialist

A quality repair in an EASA service center will yield a motor or pump that will meet just about any vibration spec­ification. And good EASA technicians could use their “finger vibrometer” to verify that. However, a large number of EASA customers demand a more formal means of verifying acceptably smooth operation. 

A few sophisticated customers have developed their own vibra­tion standards, but most depend on standards organizations such as the National Electrical Manufacturers As­sociation, or NEMA (electric motors), the Hydraulic Institute (HI) (pumps) and the International Organization for Standardization (ISO). There are also industry specific standards organiza­tions such as the American Petroleum Institute (API) for refineries and the Submersible Wastewater Pump As­sociation (SWPA). A working knowl­edge of the various standards will be beneficial for EASA service center technicians and managers.

This video walks through the steps to adjust and set end play on a typical vertical hollow shaft pump motor. Proper end play adjustment is important to keep the lower bearing from supporting the weight of the rotor and to allow for thermal growth within the motor.

The motor in this video has a thrust bearing in the top and a standard ball-type guide bearing in the bottom, which is typical of vertical pump motors. There are other bearing arrangements with somewhat different procedures for setting end play, but here we’ll be working with the most common arrangement and procedure. There are variations of this process, and some vertical pump motor bearing arrangements require special procedures, especially those with springs mounted under a spherical roller thrust bearing.

Topics covered include:

• Tools and supplies needed
• Basic principle of end play adjustment
• How to adjust end play
• How to measure and verify proper end play

This presentation introduces you to ANSI's new shaft alignment standard. Topics covered include:

• A discussion of alignment Quality grades, AL 1.2, AL 2.2, AL 4.5
• Shaft alignment tolerances
• Issues affecting measurements
• Conditions affecting alignment stability

Target audience: This presentation benefits service center technicians and supervisors looking to improve shaft alignment knowledge and skills. 

The impeller is generally the most difficult pump component to repair and the most expensive to replace. This session will look at case histories of failed pumps and the steps to determine the cause of failure:

Topics covered include:

• Erosion, corrosion, cavitation or wear: What happened to this impeller?
• How to spot the tell-tale signs
• What operational conditions led to impeller damage

Gene Vogel
EASA Pump & Vibration Specialist

This technical paper was presented at the 2014 EASA Convention.

The impeller is generally the most difficult pump component to repair and the most expensive to replace. This paper looks at case histories of failed pumps and the steps to determine the cause of failure.

• Erosion, corrosion, cavitation or wear. What happened to this impeller?
• How to spot the tell-tale signs
• What operational conditions led to impeller damage

Gene Vogel
EASA Pump & Vibration Specialist

When repairing centrifugal and axial flow pumps, axial thrust is a concern. An understanding of the causes and the mitigating provisions of various pump designs will help repair technicians to ensure those provisions work properly. Various impeller designs, end suction and vertical turbine pumps will be a primary focus. 

Primary topics are: 

• Factors affecting the amount of axial thrust developed by an impeller 
• Review of some common mitigation designs 
• What repair technicians need to look for on various pump designs 

The mechanical pump components can be repaired without understanding the hydraulics of how a pump works. But it’s easy to miss important features that can affect pump performance and reliability.  

This presentation will be helpful for pump repair technicians and supervisor and engineers associated with pump repair.

Gene Vogel
Especialiste de Bombas y Vibraciones

Al igual que con la mayoría de las otras máquinas reparadas comúnmente en los centros de servicio de EASA, el balanceo dinámico de los impulsores de las bombas es una cuestión importante. El desbalanceo excesivo imparte fuerzas sobre los rodamientos, reduciendo su vida útil y sometiendo los soportes de las máquinas a una energía vibratoria que deteriora las fundaciones.

Desde la perspectiva del balanceo dinámico, los rotores de las bombas difieren mucho de los de los motores eléctricos más populares. La masa del rotor de un motor eléctrico se encuentra entre los rodamientos y la longitud de los rotores exceden a sus diámetros. Muchos impulsores de las bombas se encuentran montados en voladizo y es probable que sean más angostos que sus diámetros. Los componentes angostos pueden requerir reglas especiales para asignar el desbalanceo residual permisible (según ISO 21940-11), y pueden ser necesarias técnicas especiales para un balanceo eficiente en la máquina balanceadora.

By Gene Vogel
EASA Pump & Vibration Specialist

Vertical turbine pumps (VTPs) are workhorses in the petrochemical, power generation and manufacturing industries, and prolific in municipal water applications that handle the primary intake load. The ability to develop high head with multiple impeller bowls—coupled with the ubiquity of standard vertical motors that can support heavy pump shaft loads—makes VTPs a good choice. Although these machines are ruggedly built, abrasive sediments in the pumpage take a toll, particularly on line shaft and pump bowl bearings, so periodic overhauls are often necessary. Rather than simply replacing the bearings, however, it is important that repairs address all of the issues needed to restore maximum operating life.

This article covers:

• Common repairs
• Fit and alignment
• Bearing-to-shaft clearances
• Primary repair concerns

READ THE ARTICLE

Gene Vogel
Especialista de Bombas & Vibraciones de EASA

Es común encontrar impulsores de bombas con daños significativos en la superficie. Las tres causas más comunes de daño superficial son la erosión, la corrosión y la cavitación. En cada uno de estos problemas existen características que ayudarán a indicar la causa primaria de fallo por lo que será útil una breve descripción de cada uno de estos tres fenómenos. La erosión es la más sencilla; esta simplemente es el desgaste de las superficies del impulsor ocasionada por los materiales abrasivos suspendidos en el bombeo. La corrosión también es simple ya que es una reacción química entre las moléculas ionizadas en el bombeo y los elementos metálicos del impulsor. La oxidación es la corrosión más común en los impulsores de las bombas. La cavitación es un fenómeno más complejo y tiene que ver con la formación e implosión de burbujas en el bombeo debido a los cambios de presión presentes cuando el bombeo fluye a través del impulsor. La baja presión en la succión permite que se formen burbujas de vapor y luego estas burbujas implosionan a medida que aumenta la presión a través del impulsor. La apariencia del daño en las superficies del impulsor refleja las características de cada uno de estos tres fenómenos.

Gene Vogel
Especialista de Bombas and Vibraciones de EASA

En el principio, Dios hizo circular el agua libremente por toda la tierra. Entonces el hombre hizo las bombas para hacer fluir el agua donde él quería. Entonces Dios creó las fugas y el hombre creó los sellos de las bombas. Dios sonrió. El hombre continuó luchando contra las fugas en los sellos.

Para aquellos que son nuevos en el negocio de la reparación de bombas, los sellos pueden resultar intimidantes, sin embargo, es bien conocido que los sellos mecánicos de las bombas son dispositivos temperamentales que fallan con frecuencia. El hecho es que los sellos mecánicos son dispositivos simples que a menudo son utilizados de forma inadecuada, algunas veces instalados incorrectamente o tal vez montados en bombas que no son aptas para la aplicación. En la mayoría de las aplicaciones, los sellos mecánicos son lo suficientemente macizos para tolerar condiciones de operación y de manejo menos óptimas. Para aplicaciones exigentes todo debe estar bien.

Gene Vogel
EASA Pump & Vibration Specialist

In the beginning, God made water to run freely over the earth. Then Man made pumps to make water run where he wanted it. Then God made leaks. Then Man made pump seals. God laughed. Man continues to struggle with leaking pumps seals.

For those new to pump repair, mechanical seals can be intimidating. It is commonly known that pump mechanical seals are temperamental devices that fail frequently. The fact is, mechanical seals are simple devices that are often misapplied, sometimes installed incorrectly, or perhaps installed on pumps that are not well suited for the application. For many applications, the mechanical seal is robust enough to tolerate less than optimal handling and operating conditions. For more demanding applications, everything must be right.

Gene Vogel
EASA Pump & Vibration Specialist

For many larger centrifugal pumps, there are options for installing “component” or “cartridge” mechanical seals. Understanding the advantages and limitations of each will allow you to recommend the best solution for customer applications.

Gene Vogel
EASA Pump & Vibration Specialist

It’s common to find pump impellers with significant surface damage. The three most common causes of surface damage are erosion, corrosion and cavitation. For each of these there are characteristics which will help indicate the primary cause of the damage.

A brief description of each of the three phenomenon will be helpful:

• Erosion is the simplest; it is simply the wear to the impeller surfaces from abrasive materials suspended in the pumpage.
• Corrosion is also straightforward; corrosion is a chemical reaction between ionized molecules in the pumpage and metallic elements of the impeller. Oxidation is the most common corrosion on pump impellers.
• Cavitation is a more complex phenomenon. Cavitation is all about bubbles forming and imploding in the pumpage due to the pressure changes that occur as the pumpage flows through the impeller. Low pressure at the suction allows vapor bubbles to form and then these bubbles implode as the pressure increases through the impeller.

The appearance of the damage to the impeller surfaces reflects the characteristics of the each of these three phenomenon.

Gene Vogel
EASA Pump and Vibration Specialist

When talking with various pump manufacturers and mechanical seal suppliers, you’re likely to encounter a variety of recommendations. (Some are complementary and some are contradictory.) With the variety of seal types, materials and pump designs, it is inevitable that what works well for one mechanical seal installation may not work for others. We will explain some good general practical considerations that will help service centers make judgments about the best techniques for the pumps they may encounter.

Gene Vogel
Especialista de Bombas y Vibraciones de EASA

Las bombas de turbina verticales (VTP) son accionadas por motores verticales provistos con grandes rodamientos de empuje que soportan el peso del rotor del motor, el rotor de la bomba y el empuje dinámico hacia abajo, producido por los impulsores cuando levantan el líquido. El peso del rotor del motor y del rotor de la bomba se determinan fácilmente a partir de datos de ingeniería simples.  El cálculo del empuje producido por los impulsores cuando interactúan con el líquido en movimiento es mucho más difícil y no siempre el empuje es generado hacia abajo.

Durante ciertas etapas de la operación de la bomba, el flujo del líquido a través de los impulsores puede generar un empuje hacia arriba que puede elevar el conjunto rotativo de la bomba. La fuerza ascendente resultante puede causar estragos en los rodamientos de empuje del motor que posiblemente solo están diseñados para manejar el empuje hacia abajo.

En este artículo revisemos brevemente cómo se produce el empuje hacia arriba en las bombas y las disposiciones en los motores VTP diseñados para controlarlo.

Gene Vogel
Especialista de Bombas & Vibraciones de EASA

Esto sucede en casi todos los centros de servicio de EASA, aparece una máquina para reparación, con cables y un motor, pero es una bomba. A menudo es una bomba sumergible o de acoplamiento cerrado. Si su respuesta es: “Aquí no reparamos estos equipos” y está pensando: “Nosotros no sabemos nada sobre reparación de bombas” puede que le esté dando la espalda a un trabajo muy rentable.

Como ya detallé en mi artículo publicado en Febrero en la revista Currents, la reparación de bombas puede ser un área de expansión muy rentable para los centros de servicio especializados solo en la reparación de motores eléctricos. Si usted está de acuerdo en que la reparación de bombas sería una buena opción para su negocio, el próximo paso consiste en evaluar qué cambios necesita en sus instalaciones para incluir la reparación de bombas. Encontrará que ya tiene gran parte del equipo necesario. Las características de los motores y de las bombas centrífugas son muy similares y dependiendo del tipo de bomba, puede que necesite muy poco equipo adicional.

Gene Vogel
EASA Pump & Vibration Specialist

Una de las reparaciones más comunes en las bombas centrífugas consiste en reemplazar los anillos de desgaste deteriorados o dañados. En las bombas con impulsores cerrados (con una cubierta frontal como se describe más adelante), habrá un anillo de desgaste en la carcasa y posiblemente un anillo de desgaste en el impulsor, que se ajusta al diámetro exterior (OD) del ojo de succión. Los impulsores también pueden tener anillos de desgaste traseros que son importantes para controlar el empuje axial. Las bombas con impulsores abiertos generalmente no tienen problemas con la tolerancia del anillo de desgaste del ojo de succión, pero a menudo tienen anillos de desgaste traseros. Las holguras entre el anillo de desgaste de la carcasa estacionaria y el anillo de desgaste del impulsor rotativo son fundamentales para un adecuado funcionamiento de la bomba. Aunque muchos fabricantes de bombas proporcionan tolerancias y dimensiones correctas, otro no lo hacen; en la actualidad existen una gran cantidad de bombas de fabricantes antiguos que ya han desaparecido, donde los datos de las dimensiones simplemente no están disponibles.

Gene Vogel
EASA Pump & Vibration Specialist
and
Don Scaturro
Illinois Electric Works, Inc., Granite City, IL

Pump packing is a high maintenance item for any centrifugal pump so equipped, and unacceptable for chemical pumping applications. This paper covers how service centers can convert a pump from packing to mechanical seals to:

• Eliminate a maintenance issue for customers
• Allow an available pump to be put into alternate service requiring mechanical seals

This paper is an overview of such a conversion on a 50 hp split-case pump.

Bret McCormick
Stewart's Electric Motor Works, Inc.

Paperwork.

No one likes it on the shop floor. Nobody wants to fill out forms. 

Like most service centers, we recognize that accurate paperwork is a necessary part of any effective system for achieving product quality. But in our experience, it’s always been difficult to develop easy-to-use forms that will streamline the process of moving jobs through the shop. With those thoughts in mind, we at Stewart's Electric Motor Works set out to find a better way to create user-friendly forms.

We started by cramming a lot of information onto a single sheet of paper and, after much discussion, eventually settled on a template that could be used to expand the paperwork of each department.

To simplify the process of making specific repair forms, we used the Tables function in Microsoft® Word to create more than 60 building blocks for capturing common information like nameplate data, flux densities, accessories, instructions/notes, and so forth. We also developed a small library of generic drawings (e.g., horizontal and vertical motors, rotors, armatures, pump components, etc.) that could be incorporated into forms as needed.

Now whenever we need a new form, we just paste the appropriate building blocks into the department’s template and save the document with a new file name. Then we move the blocks around on the page as needed, modifying the labels, cell sizes, and numbers of rows as necessary before saving the document again. With this procedure, it’s fairly easy to create or revise forms for all aspects of repair–from motor and pump inspection and disassembly to machine work, rewinding, reassembly and final testing.

Since this process works so well for us at Stewart’s Electric, it might be helpful to you, too. You can download and view our building blocks, illustrations and generic PDF forms by downloading the ZIP file below (ZIP is an archive file format that contains multiple files or directories that may have been compressed. If you are not familiar with extracting content from ZIP files, see this Microsoft Support page for instructions.)

To create your own form in MS Word®  or MS Publisher®, simply download the building blocks you need. Then cut, paste, resize and move them around on the page to make a form that best fits your company’s needs. (Tip: Ask your children or grandchildren if you need help learning how to cut and paste. :-)

The generic PDF forms may be what you need, so you may choose to use them “as is.” 

If you need more ideas on what to include on your forms, see Section 2.17 in EASA’s Technical Manual located online in the EASA Resource Library.

Download the file using the link below.

Gene Vogel
EASA Pump & Vibration Specialist

Whether it is a simple re-application of a pump from 50 Hz to 60 Hz (or vice versa), the repurposing of an existing pump, or the application of a new pump to an existing application, determining the proper trim for an impeller can be challenging. This presentation reviews: 

• Basic impeller design criteria 
• Methods of evaluating the head and flow and power implications of trimming impeller outside diameters

This recording will benefit pump technicians, engineers and sales personnel.

Jerry Gray
Sloan Electromechanical Service & Sales

This is your marketing advantage! By making the choice to market pump services, your firm is evolving to an equipment  efficiency and reliability consultant, creating a marketing message of equipment systems service – not just component repair or component replacement. Are you ready to learn, invest and grow!

Performing pump repair is a natural extension of the motor service center. Generally speaking, motor service center technicians have the skills necessary to provide pump repair. And when they’re EASA members, they have so much more to offer!

The challenge, though, is developing a winning strategy by proving to the customer that his or her services are superior to those of others.

Gene Vogel
EASA Pump and Vibration Specialist

One drip per minute amounts to about a liter (quart) of water in 3 days. If that’s the leak rate for an O-ring on a submersible pump, that’s a big problem. O-rings are common for static seals on submersible pumps. An understanding of what makes a good static seal, and what causes them to leak, is obviously important for pump repair technicians.

Gene Vogel
EASA Pump & Vibration Specialist

As with most other machines commonly repaired in EASA service centers, dynamic balancing on pump impellers is an important concern. Excessive imbalance imparts forces on bearings, reducing their lives and subjecting machine mountings to vibratory energy that deteriorates foundations.

Pump rotors are quite different than more familiar electric motor rotors from a dynamic balance perspective. The mass of an electric motor rotor is between the bearings, and the rotors are longer than their diameters. Many pump impellers are mounted in an overhung configuration, and the impellers will likely be narrower than their diameters. Narrow components may require special rules for allocating allowable residual imbalance (per ISO 21940-11), and special balancing techniques may be needed for efficient balancing in the balancing machine.

Until now, governmental and market forces have tried to reduce electrical energy usage in industry primarily by targeting electric motors. While these “green” initiatives have often raised concerns for manufacturers, repair facilities and end users, they have also spurred innovation.

But the commercial and regulatory landscape continues to evolve, and the horizon coming into view includes a new focus on pumps and pump systems. Starting in January 2020, the U.S. Department of Energy (DOE) will begin implementing the first ever energy efficiency standards for freshwater rotodynamic (centrifugal and axial flow) pumps. These standards will directly affect pump manufacturers and, to a lesser extent, the pump repair market, while ultimately benefiting end users if the new focus can reduce their energy costs.

READ THE ARTICLE

The pump repairs are completed! Now the pump needs to be tested. This presentation discusses the procedures for the basic tests that can be performed on pumps that have been repaired in the service center.

Final testing of pumps can include:

• Operational tests
• Seal leakage test
• Motor chamber leakage test (submersibles)
• Casing pressure test

While some of these tests are not difficult to perform, knowing the methods and limits will help service centers to confidently deliver quality pump repairs.

The repair of the various types of pumps represents an important segment of the service center repair market. Electric motors and pumps are the two most widely used industrial machine components.

Although there are two principle pump types (dynamic and positive displacement), this manual focuses on dynamic pumps and the fundamentals of dynamic pump repair. The information it contains will be helpful to both novice and experienced pump repair technicians, to supervisors and managers of pump repair operations, and to customer service and sales personnel who communicate with customers about pump repair issues.

Section 2 covers repair concerns and techniques common to most pumps, while the following sections focus on specific pump types and the unique concerns associated with repairing them. These sections include submersible pumps, vertical turbine pumps, end suction pumps and split case pumps. Where appropriate, these sections may reference the general repair information in Section 2.

Table of Contents- (Download the complete Table of Contents)

1. Nomenclature
2. General Pump Repair Procedures
3. Submersible Pumps
4. Vertical Turbine Pumps
5. End Suction Radial Split Pumps
6. Axial Split-Case Pumps
7. Seals
8. Pump Reliability
9. Glossary and Standards Organizations

Gene Vogel
EASA Pump & Vibration Specialist

Service centers that provide field service for equipment removal and installation have little trouble handling most common horizontal pumps. However, vertical turbine pumps (and similarly mounted vertical pumps) present some additional challenges. Vertical pumps of this style use the discharge column to suspend the pump below grade from a grade mounted discharge casing. The casing provides the support for the pump, the pedestal for the vertical drive motor, and a 90 degree discharge elbow. The discharge elbow may be above or below grade.

The initial challenge for pump removal is presented by the length of the pump. Short set pumps range to about 50 ft. (15 meters) in overall length, minus the drive motor. Deep set pumps can extend hundreds of feet (or meters) into a well or sump. The designation as short set or deep set is somewhat arbitrary, depending on the working height of the available crane to lift the machine. A short set pump could be handled as a single piece (again, less the motor). But if the length of the pump exceeds the working height of the crane, then field disassembly is necessary – usually referred to as a deep set pump.

Topics covered include:

• Documenting the condition of the machine
• Overhead clearances
• Reinstalling the pump
• Tests

Presented by Sarah Widder and Nate Baker
Cadeo

As COVID-19 and its physical and economic impacts reshape new and existing industrial and commercial systems, operators are looking at how to most efficiently run existing commercial and industrial spaces that may be used very differently in the future.

While adding variable speed capability in commercial buildings is not a new idea, a new analysis confirms major energy and cost savings is available by pairing those products with a power drive system (PDS) – regardless of a pump’s load variability. A PDS combines an electric motor, adjustable speed controls and sensors that provide feedback to the equipment, allowing the equipment to slow down or speed up to meet current demand. This idea and the added flexibility a PDS can provide may be even more important as we move forward in uncertain times.

Speaker Bios
Sarah Widder
Sarah Widder is currently a director at Cadeo, an energy efficiency consulting firm that works with utilities, non-profits, industry and regulatory agencies to promote adoption of energy-saving technologies and practices in the marketplace.  In her current role, Sarah has been working with the Northwest Energy Efficiency Alliance and other trade associations to develop market transformation programs for motor driven equipment under NEEA’s Extended Motor Products (XMP) Initiative.  Sarah started working on motor-driven technology in her previous job at Pacific Northwest National Laboratory, where she supported test procedure development for the U.S. Department of Energy (DOE) and led development of a new test procedure and efficiency metric for pumps, the Pump Energy Index (PEI).  Sarah has a B.S. in Chemical Engineering from the University of Washington and a PhD in Civil Engineering from Washington State University.    

Nate Baker
As a senior associate and member of Cadeo's engineering team, Nate Baker leverages his background in industrial facilities to support energy efficiency program design and regulatory review. Most recently, his work has focused on supporting efforts to increase energy efficiency in motor-driven equipment and adoption of energy efficient technology in commercial and industrial applications broadly. His research has supported program development by establishing unit energy savings estimates for pumps and fans and documenting operational characteristics of clean water pumps. Nate also provides technical expertise to support the development of energy conservation standards and test procedures.

Gene Vogel
EASA Pump & Vibration Specialist

Vertical turbine pumps (VTP) are driven by vertical motors with large thrust bearings that support the weight of the motor rotor, the pump rotor and the dynamic down-thrust generated by the pump impellers as they lift the liquid. The weight of the motor rotor and pump rotor are easily determined from simple engineering data. The amount of thrust generated by the impellers as they interact with the moving liquid is much more complicated, and the thrust is not always generated in the downward direction.

During certain stages of pump operation, the flow of the liquid through the impellers can generate an upward thrust that can lift the pump rotating assembly. The resulting upward force can cause havoc with thrust bearings in the motor which may be designed to handle only down-thrust. 

This article will briefly review how pump up-thrust occurs and the provisions of VTP motors designed to control it.

Gene Vogel
EASA Pump & Vibration Specialist

Vertical turbine pumps depend on the vertical motor's thrust bearings to support the combined weight of the pump rotor and the motor rotor and to counteract the dynamic down-thrust that the pump impellers generate in lifting the liquid.

READ THE FULL ARTICLE

Eugene Vogel
EASA Pump and Vibration Specialist

When working with pumps, you are sure to encounter instances where the pump curve is referenced, along with a number of parameters associ­ated with it. A key parameter of the pump curve is the Best Efficiency Point (BEP). This simple concept of an operating point that yields the most efficient operation is not difficult to visualize. For electric motors, efficiency varies with load; the best efficiency be­ing at about 75% load. However, with rotodynamic pumps – which include centrifugal and axial flow pumps – there are four key parameters to be considered, one of which is efficiency. These four parameters are head, flow (aka capacity or volume), power and efficiency.

Nota del editor: Este artículo técnico "repetido" fue publicado por primera vez en la edición de Currents de enero del 2012.

Eugene Vogel
Especialista de Bombas y Vibraciones de EASA

Cuando trabaje con bombas, seguramente encontrará instancias en las que se hace referencia a la curva de la bomba, junto con una serie de parámetros asociados con ella. Un parámetro clave de la curva de la bomba es el Punto de Mejor Eficiencia (BEP). Este concepto simple de un punto de operación que produce la operación más eficiente no es difícil de visualizar. Para motores eléctricos, la eficiencia varía con la carga; la mejor eficiencia está en alrededor del 75% de carga. Sin embargo, con las bombas rotodinámicas, que incluyen bombas centrífugas y de flujo axial, hay que considerar cuatro parámetros clave, uno de los cuales es la eficiencia. Estos cuatro parámetros son cabeza, caudal (también conocido como capacidad o volumen), potencia y eficiencia.

Gene Vogel
EASA Pump & Vibration Specialist

It happens to just about every EASA service center. A machine shows up for repair; it has leads, and there’s a motor, but the machine is a pump. Most often, it’s a close-coupled pump or a submersible pump. If your response is, “We don’t work on those here,” because you’re thinking, “We don’t know anything about repairing pumps,” you may be turning your back on some very profitable work.

As I detailed in my February Currents article, pump repair can be a very profitable expansion area for service centers that specialize in electric motor repair only. If you agree that pump repair would be a good fit for your business, the next step is to evaluate what changes your facility needs to accommodate repairing pumps. You will find that you have much of the necessary equipment from repairing electric motors. The mechanical characteristics of motors and centrifugal pumps are very similar. Depending on the type of pump, there may be very little additional that you need.

Doug Moore
Kentucky Service Co., Inc.

Many EASA members perform service on pumps of some type and have had the customer return the pump or call back to say it leaks or it still will not pump. We solved this by making a very inexpensive test center for all types of pumps: flooded suction, immersion lube, submersible, centrifugal, deep well and many others.

Doug Moore
Kentucky Service Co., Inc.

In today’s world, working on pumps can be hazardous to your health — if you don’t take the proper precautions. Great care should be taken to protect yourself and your employees from what could cause long-term health issues from the job.

Gene Vogel
Especialista de Bombas & Vibraciones de EASA

Cuando EASA adoptó el eslogan “The Electro-Mechanical Authority,” esto fue mucho más que una acción superficial. Mientras el negocio de la reparación de motores eléctricos es una actividad que genera valor para la gran mayoría de centros de servicio asociados a EASA, las máquinas rotativas de todo tipo son un segmento importante del negocio de la reparación y de la rentabilidad general de los centros de servicio. Junto con los motores eléctricos, las bombas roto-dinámicas (bombas centrífugas y de flujo axial) son la categoría más grande de máquinas reparadas en los centros de servicio adscritos a EASA. Las razones para la expansión en el segmento de la reparación de bombas son evidentemente claras: 

• Las bombas son máquinas costosas y normalmente no son fabricadas en dimensiones convencionales. Los motores eléctricos NEMA e IEC fabricados en serie, son máquinas básicas y varían muy poco entre un fabricante y otro. Pero las bombas están mucho menos estandarizadas. No existen carcasas estándar para dos de las bombas más comunes: Las sumergibles y del tipo turbina vertical. 
• En muchas aplicaciones, el corazón de la bomba, el impulsor (impeller) se mecaniza a una medida especial para que trabaje en una aplicación específica. Los repuestos requieren un tiempo de entrega prolongado, haciendo que la reparación sea una opción mucho más viable.  
• En tiempos de recesión económica, los principales segmentos de aplicaciones de bombas son seguros. El agua municipal, las aguas residuales y el control de inundaciones tienen una financiación y demanda estables. 

Los centros de servicio miembros de EASA que buscan expandirse o que estén interesados en reemplazar los mercados de reparación volátiles existentes, han visto en la reparación de las bombas algo idóneo. Por lo general, la mayoría de los mismos repara bombas roto-dinámicas. Por mucho, las bombas son la categoría más grande de máquinas accionadas por motores eléctricos.

Si un centro de servicio está reparando motores eléctricos, entonces es casi seguro que algunos de estos motores estén accionando bombas y que con sus clientes actuales existan perspectivas para reparar las bombas.

Gene Vogel
EASA Pump & Vibration Specialist

Vertical turbine pumps (VTP) commonly have rotors with multiple mixed-flow impellers (sometimes 12 or more) that are supported by a vertical pump motor. Such designs offer a lift adjustment for raising or lowering the pump rotor to properly position the impellers within the bowl. Depending on the type of pump, this may be critical for maximizing pump efficiency and could have a significant impact on motor load (current) and reliability. Given the importance of VTP lift adjustments, it is necessary to recognize that procedures vary with the characteristics of the pump and motor.

READ THE FULL ARTICLE

Eugene Vogel
EASA Pump & Vibration Specialist

It is common for vertical turbine pumps (VTP) to be designed with mul­tiple mixed flow impellers (sometimes 12 or more) and for the pump rotor to be supported by the vertical pump mo­tor.

Vertical pump motors can be solid shaft or hollow shaft. Solid shaft motors have an annular keyway in the shaft that is engaged by a solid coupling that supports the pump rotor. 

Hollow shaft motors support and drive the pump rotor from the top by means of a head shaft fitted through the hollow motor shaft to the pump line shaft. In either case, there is an adjustment that lifts the pump rotor so it is supported by the motor shaft. This adjustment is obviously critical to the proper operation of the pump and motor and can have a significant effect on the motor load (current). Presented here are some of the main concerns for setting this pump lift ad­justment.

Anyone dealing with installed machinery, or even test running motors in the service center, will encounter instances where structural resonance is amplifying machine vibration. The machine may meet stringent specifications in one instance but exceed acceptable vibration levels in another. A good understanding of natural frequencies and the tests necessary to identify them will help solve these vexing situations.

This presentation covers:

• What is a natural frequency and why do they exist
• How to conduct a basic bump test with a single channel analyzer
• What is a modal analysis and what additional information does it provide
• Related tests and concerns

This webinar is useful for service center technicians, supervisors and managers.

Gene Vogel
Especialista de Bombas & Vibraciones de EASA 

El artículo de la revista Currents de noviembre del 2023: “Pautas Para el Fluido de Sellado de las Bombas Sumergibles” cubre las opciones para el aceite de sellado de las bombas sumergibles. Además del aceite de sellado, algunas bombas sumergibles tienen una cavidad del estator llena de aceite. Este aceite transfiere de manera muy eficiente el calor desde el devanado y el núcleo del estator, y especialmente desde el rotor, hasta la carcasa de la bomba, donde la convección lo lleva al líquido de bombeo en el que está sumergida. Si bien las especificaciones para el aceite de sellado son bastante flexibles, el aceite de la cavidad del estator tiene más restricciones.

Gene Vogel
Especialista de Bombas y Vibraciones de EASA

Las bombas sumergibles son máquinas reparadas habitualmente en los centros de servicio de EASA. Casi todas tienen sellos dobles, un sello superior (interior) y un sello inferior (exterior). La cámara entre esos dos sellos se denomina cámara de sellado y estará llena con algún tipo de fluido barrera. El fluido barrera más común es el aceite; aunque algunos modelos (Figura 1) están diseñados con una solución de glicol. El fluido barrera adecuado para cada modelo de bomba aparecerá en el manual de operación y mantenimiento (O&M) de la bomba, y la principal recomendación de EASA es utilizar el fluido especificado. En casos en que no se pueda encontrar o no esté disponible el fluido especificado para la reparación, este artículo ofrece algunas pautas generales que se pueden seguir.

Gene Vogel
EASA Pump and Vibration Specialist

When a motor fails to perform, we know what to check: the voltage, whether it’s balanced, the current, whether there is a ground, etc. When a pump fails to perform, many service centers are at a loss on how to troubleshoot it. If the pump has just been repaired and fails to perform, it will be hard to convince the customer that the pump is not the problem. The fact is, there are three areas of possibilities: It could be the pump, or it could be the fluid that is being pumped (the pumpage), or it could be the system of vessels, pipe and fittings connected to the pump (the system).
Understanding a little bit about pump curves and pump performance parameters, and using the process of elimination, will allow the service center technician to narrow the possibilities — especially those that are pump related.

By Gene Vogel
EASA Pump & Vibration Specialist

An important step when selecting a centrifugal pump and an electric motor for an application or when troubleshooting operation issues is to determine how much power the pump should be using. The “by-the-book” approach references the pump curve, which shows the power requirement for the pump’s range of operation (head and flow rate). While that’s the best approach, a simple, universal formula based on the relationship of power, head, flow rate, and efficiency can provide realistic estimates for general planning or primary troubleshooting.

READ THE FULL ARTICLE

Gene Vogel
EASA Pump & Vibration Specialist

Probablemente todo el mundo se encuentra familiarizado con el impacto de los esfuerzos de la eficiencia energética en nuestra industria. Esto ha sido una preocupación y un incentivo para la innovación en los motores eléctricos. Los miembros de EASA y los fabricantes han sido moldeados por las fuerzas gubernamentales y del mercado, destinadas a reducir el uso de la energía eléctrica. Los motores eléctricos son un objetivo primordial de estos esfuerzos "verdes".

Pero el panorama comercial y regulatorio se encuentra en constante evolución y el horizonte que se vislumbra incluye un nuevo enfoque para las bombas y los sistemas de bombeo. El Departamento de Energía de los EE. UU. (DOE) está implementando normas de eficiencia para las bombas rotodinámicas (bombas de flujo centrífugas y axiales). Las normas tendrán poco efecto en el mercado de reparación mientras que los fabricantes se verán directamente afectados. Pero la eficiencia de una bomba es muy diferente a la de un motor eléctrico.

Incluso los estamentos reguladores que escriben los requisitos de eficiencia para las bombas entienden que es el sistema al que está conectada la bomba lo que determina su eficiencia. Tanto Hydraulic Institute (HI) como CSA Group tienen iniciativas en camino para establecer normas para medir y reportar la eficiencia de los sistemas de bombeo.

Este interés emergente en la eficiencia de las bombas y de los sistemas de bombeo, crea oportunidades para los miembros de EASA involucrados en la reparación de bombas que representan a los proveedores o que puedan estar moviéndose en esa dirección.

Gene Vogel
EASA Pump & Vibration Specialist

Everyone is probably familiar with the impact of energy efficiency efforts on our industry. For electric motors, this has been both a concern and an incentive for innovation. EASA members and manufacturers have been shaped by the governmental and market forces aimed at reducing electrical energy usage. Electric motors are a primary target of these “green” efforts.

But the commercial and regulatory landscape is ever evolving, and the horizon coming into view includes a new focus on pumps and pump systems. The U.S. Department of Energy (DOE) is implementing efficiency standards for rotodynamic pumps (centrifugal and axial flow pumps). The standards will have little effect on the pump repair market, while pump manufacturers are directly affected. But pump efficiency is very different from electric motor efficiency.

Even regulators writing the efficiency requirement for pumps understand that it is the system to which the pump is connected that dictates the efficiency of the pump. Both the Hydraulic Institute (HI) and the CSA Group have initiatives in progress to set standards for measuring and reporting pump system efficiency.

This emerging interest in pump and pump system efficiency creates opportunities for EASA members involved in pump repair, who represent pump vendors, or who may be moving in that direction.

Gene Vogel
EASA Pump & Vibration Specialist

The repair of roto-dynamic pumps (pumps with centrifugal and axial flow impellers) requires that, as much as possible, the mechanical condition of the pump be returned to factory specifications. This presentation focusses on critical close fit tolerances and certain surface finish specifications. The best recommendation is always that factory tolerances be used. However, when those factory tolerances are simply not available and the pump must be repaired, service centers rely on general rules of thumb and experience to complete repairs. 

The following concerns will be reviewed: 

• Rolling element bearings
• Sleeve bearings (horizontal)
• VTP bearings
• Impeller-casing wear rings
• Casing rabbets
• VTP motor mounting flange runout and P-flange type motor bases
• Throttle (throat) bushings
• Impeller-shaft fit
• Stage bushings

This summary of data, collected from various service centers, pump manufacturers, parts manufacturers and engineering resources, assembled in one resource, will be helpful to pump repair technicians, supervisors and engineers.

This presentation covers:

• Brief overview of disassembly and evidence of failure
• Discussion of possible failure scenarios
• Review of actual repairs, modification and reassembly
• Update of machine's present operation

Presented by Gene Vogel
EASA Pump & Vibration Specialist

The EASA Pump Reliability Seminar is a two-day program that describes in detail the factors related to pump reliability. This webinar introduces participants to those factors and how they come together to ensure a reliably operating pump. Not everyone needs to be a pump expert, but they should know the essentials of reliability to recognize when more expertise is needed.

• Pump reliability factors
• Pump applications
• Pump failure modes

This top-level view will be useful to service center managers, sales personnel, engineers and technicians who encounter pumps in the scope of their work.

Bret McCormick
Stewart’s Electric Motor Works, Inc. 
 
The following is an example of how Stewart’s Electric Motor Works was able to provide valuable new service to an existing customer. I hope you can benefit from this case study.

One of our municipal customers was experiencing diminished flow rates and severe leaking from an ITT 600 hp, 1200 rpm split case pump. The pump was brought to our facility for evaluation.

We found its overall condi­tion to be in serious disrepair. The rust and scale from years of service had built up around the packing; the inside of the pump had rust blooms through­out. The shaft sleeves were worn out and the sealing glands were bent. One of the bearing journals was worn and the other had broken.

A special discounted collection of 8 webinar recordings focusing on various aspects of pump repair.

Once purchased, all 8 recordings will be available on your "Downloadable products purchased" page in your online account.

Downloadable recordings in this bundle include:

Troubleshooting Pump Performance Problems
Presented May 2017

This presentation covers:

• Not enough pressure (head) or not enough flow – how do you respond?
• How to determine if a pump is operating properly
• Differentiating a pump problem from a system problem
• Determining pump load and power requirements
• The effect of fluid parameters and cavitation on pump performance. 

Target audience: This will be most useful for service center technicians and engineers. The content will also be beneficial for supervisors and managers who are responsible for pump failure analysis and testing. 

Pump Failure Case Study
Presented December 2013

This presentation covers:

• Brief overview of disassembly and evidence of failure
• Discussion of possible failure scenarios
• Review of actual repairs, modification and reassembly
• Update of machine's present operation

Repair Tips for Submersible Pumps
Presented February 2013

This presentation focuses on:

• Types of submersible pumps
• Tips on seal arrangements
• Common repair procedures
• Cables and cable entries
• Testing submersibles in the service center

Assessing Impeller Damage
Presented May 2019

The impeller is generally the most difficult pump component to repair and the most expensive to replace. This session will look at case histories of failed pumps and the steps to determine the cause of failure. Topics covered include:

• Erosion, corrosion, cavitation or wear: What happened to this impeller?
• How to spot the tell-tale signs
• What operational conditions led to impeller damage

Repairing Impeller Damage
Presented May 2016

We’ve covered how to assess impeller damage. Now learn how to fix that damage. This presentation covers: 

• Replacing/repairing wear rings
• Repairing cavitation damage
• Impeller replacement options
• Dynamic balancing impellers

Techniques for Straightening Pump Shafts
Presented March 2011

The slender dimensions of many pump shafts make them susceptible to distortion, which affects pump performance and reliability. This recording presents a methodical approach and effective techniques for measuring and correcting shafts which are bent or twisted.

Target audience: This presentation is intended for service center supervisors, managers and machine shop technicians.

Vertical Turbine Pump Repair Tips
Presented February 2012

Vertical turbine pumps are used extensively in every segment of industry. Although they are not complex, repairing them in the service center can present a few challenges. This presentation gives some approaches and procedures that experience has shown will make the job easier.

Final Testing for Pumps - An Overview
Presented November 2014

The pump repairs are completed! Now the pump needs to be tested. This presentation discusses the procedures for the basic tests that can be performed on pumps that have been repaired in the service center.

Final testing of pumps can include:

• Operational tests
• Seal leakage test
• Motor chamber leakage test (submersibles)
• Casing pressure test

While some of these tests are not difficult to perform, knowing the methods and limits will help service centers to confidently deliver quality pump repairs.

This presentation focuses on:

• A review of seal basics
• Seal materials for primary and secondary seals
• How to determine spring tension values
• How to calculate PV values
• Seal flush plans

This three-part series focuses on the pump selection process.

• Part 1 - Pump System Basics
  Whether for a new pump application or for a pump replacement, it is important to understand the full range of expected operating conditions, and the system parameters dictated by those conditions. The machine mounting method, its vertical location relative to the liquid level, and environmental conditions must also be considered. This presentation addresses those concerns and introduces the process of properly selecting a pump for a particular application.
• Part 2 - Pump System Concerns
  When requesting a proposal for a new or replacement pump, a customer may provide you with specific pumping parameters, such as required head, flow and NPSH – or not. It is helpful when specifying a pump, to understand the system parameters that determine those required pumping parameters. This presentation will go over the basics of determining system parameters for pump applications.
• Part 3 - Series and Parallel Pumps
  There are many guidelines for designing multiple pumps for a single system. The most basic concern is to understand the requirements when multiple pumps are arranged in series and/or in parallel. Also, the design of systems has been become more flexible with the availability of variable speed drives, which are often applied in multiple pump installations. This presentation addresses those concerns and sheds some light on issues that result from misapplication.

A special discounted collection of 7 webinar recordings focusing on pump design thoery and how to determine is a pump is appropriate for an application.

Once purchased, all 7 recordings will be available on your "Downloadable products purchased" page in your online account.

Downloadable recordings in this bundle include:

Quick Pump Curves: How to Read Them
Presented July 2011

This presentation takes the mystery out of pump curves and provides viewers with the necessary knowledge to determine pump operating points, efficiency and horsepower. The exclusive parameters that determine if a pump is likely to cavitate are also discussed.

Target audience: This presentation is intended for application engineers, sales personnel, managers and interested pump technicians and supervisors.

The Basics: What Every Repairer Needs to Know About Pump Curves
Presented August 2016

This presentation covers:

• Head & flow = volts & amps for pumps
• Testing pumps to their performance curves
• Troubleshooting pump performance
• What the pump curve tells you about cavitation 

The Basics: What You Should Know About Pump Cavitation
Presented December 2016

This presentation covers: 

• What is classic pump cavitation?
• The NPSHA – NPSHR relationship
• How to identify the evidence of cavitation
• Other types of cavitation

Using Variable-Speed Drives to Improve Pump System Efficiency
Presented May 2018

This presentation discusses:

• Potential savings for pump operations
• How service centers can profit
• Identifying system benefits

Target audience: This webinar will benefit service center technicians and supervisors.

Pump Seals — Advanced
Presented February 2012

This presentation focuses on:

• A review of seal basics
• Seal materials for primary and secondary seals
• How to determine spring tension values
• How to calculate PV values
• Seal flush plans

Vertical Turbine Pump Shaft Journal Bearing Material, Types and Clearances
Presented December 2017

The rules of thumb often applied to journal bearings in horizontal machines don’t apply to vertical machines. Vertical turbine pumps are a common example. This presentation explains the characteristics of bearings in these pumps and provide examples of manufacturers specifications. In addition, specialty bearing materials will be discussed in regard to applications, specifications and installation.

Target audience: This webinar is most useful for service center technicians and engineers. The content is beneficial for supervisors and managers who are responsible for pump failure analysis and testing.

Vertical Turbine Pump Shaft and Bearing Types, Fits and Clearance
Presented November 2018

This presentation covers:

• Shaft material and specs
• Shaft coupling types
• Machining for shafts
• Bronze, plastic, graphite and cutlass bearing options
• Bearing clearance concerns and reference data 
• Bearing housing fits

Target audience: This webinar will benefit service center technicians and supervisors.

Gene Vogel 
EASA Pump & Vibration Specialist 

A challenge to all service centers is finding ways to differentiate themselves from every other “fix-it” facility. To the extent that service centers can offer additional services to their customers beyond basic repair, they will be able to get their customer’s attention and stand out as a value-added provider. In the arena of pump repair, there are a number of modifications that can be implemented during overhaul that will improve pump performance and reliability. The icing on the cake is that providing these upgrades can represent a source of high-profit rev­enue. Following are several options to consider: 

This presentation takes the mystery out of pump curves and provides viewers with the necessary knowledge to determine pump operating points, efficiency and horsepower. The exclusive parameters that determine if a pump is likely to cavitate are also discussed.

Target audience: This presentation is intended for application engineers, sales personnel, managers and interested pump technicians and supervisors.

Eugene Vogel
Especialista en Bombas y Vibraciones de EASA

Es común que las bombas de turbina vertical (VTP) se encuentren diseñadas con varios impulsores de flujo mixto (algunas veces 12 o más) y que los rotores de las bombas estén soportados por los motores verticales. Los motores de las bombas verticales pueden ser de eje macizo o hueco. Los motores de eje macizo tienen una cuña o chaveta anular (en forma de anillo) en el eje, para asegurar un acoplamiento sólido que soporta el rotor de la bomba.

Los motores de eje hueco soportan y accionan el rotor de la bomba desde la parte superior, mediante un cabezal de eje que está asegurado al eje lineal intermedio (line shaft) a través del eje hueco del motor. En cualquiera de los casos, existe un ajuste que eleva el rotor de la bomba para que quede soportado por el eje del motor.

Obviamente este ajuste es crítico para el funcionamiento adecuado de la bomba y el motor y puede llegar a tener un efecto significativo en la carga del motor (consumo de corriente en amperios). En este artículo se presentan algunos puntos importantes para ajustar la elevación del eje de la bomba.

This presentation focuses on:

• Types of submersible pumps
• Tips on seal arrangements
• Common repair procedures
• Cables and cable entries
• Testing submersibles in the service center

Gene Vogel
EASA Pump & Vibration Specialist

Corrosion and/or erosion damage is inevitable for some pump applications. Pumps received for repair with significant damage may look like a candidate for the junk bin, but with proper repair techniques can often be restored to original performance – or perhaps better than original. Damage from corrosion and erosion (henceforth “damage”) can occur on stationary pump components as well as on the rotating impeller. Note: Cavitation damage is a form of erosion damage.

We’ve covered how to assess impeller damage in a previous presentation. Now learn how to fix that damage. This presentation covers: 

• Replacing/repairing wear rings
• Repairing cavitation damage
• Impeller replacement options
• Dynamic balancing impellers

Gene Vogel
Especialista de Bombas & Vibraciones de EASA

En algunas aplicaciones, los daños por corrosión y/o erosión de las bombas son inevitables. Las bombas enviadas para reparación que presentan daños significativos pueden parecer buenas candidatas para ser desechadas, pero a menudo con las técnicas de reparación adecuadas pueden restaurarse a sus condiciones originales o quizás a unas mejores. Los daños por corrosión y erosión (en adelante “daño”) se pueden presentar en las partes estáticas de las bombas, así como también en el impulsor rotativo. Nota: La cavitación es una forma de daño por erosión.

Gene Vogel
EASA Pump & Vibration Specialist

Service centers are often called on to provide replacement pumps or pump motors or to advise on pump retrofit and re-application projects. A good understanding of the parameters that govern pump performance is essential to help customers with these opportunities. The information here relates to rotodynamic pumps (centrifugal and axial flow impellers) and not to positive displacement pumps.

Gene Vogel
EASA Pump & Vibration Specialist

End users or service centers often need to specify replacement pumps or pump motors, sometimes involving a retrofit or re-application project. A successful outcome depends on accurate assessment of application requirements and a good understanding of the parameters that govern pump performance. The information here relates to rotodynamic pumps (centrifugal and axial flow impellers) and not to positive displacement pumps.

• Pump ratings and power requirements
  • Sizing the pumps
  • Flow requirement
  • Head requirement
  • Cavitation
• Sizing the Motor
  • Minimum power requirement
  • Maximum power requirement

READ THE FULL ARTICLE

By Gene Vogel
EASA Pump & Vibration Specialist

High vibration is a common problem for motors that are installed on top of vertical pumps. Its source can be a mechanical issue with the pump, motor or coupling or even hydraulic forces from the pump. Structural issues involving “reed frequency” resonance often amplify the problem, but effective diagnosis must begin with an understanding of the underlying vibratory forces. Although the general vertical pump category includes submersibles, this article focuses solely on the ones that most commonly exhibit high-vibration conditions: surface-mounted pumps with the motor bolted to a pedestal on top.

Topics covered in this article include:

• Mass unbalance
• Coupling type and alignment
• Mechanical action of pump shaft & impeller
• Hydraulic action of fluid
• Resonant frequencies
• Basic frequency analysis
• Trim balancing
• Other possibilities
• Vertical pump troubleshooting checklist

READ THE ARTICLE

Bret McCormick
Stewart’s Electric Motor Works, Inc. 
Orlando, Florida
Technical Education Committee Member

Oil and water just don’t mix — espe­cially when dealing with submersible motors. Most larger sump/submers­ible pumps have oil filled cavities between the impeller and the motor to prevent water from intruding into the housing that contains the windings. In that cavity are sensors installed as part of the control circuit. 

Each manufacturer has different ideas on what kind and how many sensors are used. In this article, we’ll review some of the more common ones. Then I’ll share an experience with one I hadn’t seen before.

Gene Vogel
EASA Pump & Vibration Specialist

An important part of submersible pump repair is ensuring the power and control cable is in good condition and that cables are properly sealed where they enter the pump. This presentation addresses procedures for inspecting and testing submersible pump cables, choosing replacement cables and presents various methods that are used to seal the cables where they enter the pump, including several common potting methods.

Technicians who work on submersible pumps along with supervisors and managers will benefit from the information provided here.

Gene Vogel
EASA Pump & Vibration Specialist

Submersible pumps are a common machine repaired in EASA service centers. Almost all submersible pumps have dual seals, an upper (inner) seal and a lower (outer) seal. The chamber between those two seals is the seal chamber and it will be filled with some type of barrier fluid. The most common barrier fluid is oil; although, some models (Figure 1) are designed with a glycol solution barrier fluid. The proper barrier fluid for each model of pump will be listed in the pump operation & maintenance (O&M) manual, and EASA’s primary recommendation is to use the specified fluid. When the fluid specification cannot be found or when the specified fluid is not available for the repair, there are some general guidelines to follow that are offered here.

Gene Vogel
EASA Pump & Vibration Specialist 

“Submersible Pump Seal Fluid Guidelines,” the November 2023 Currents article, addressed options for seal oil in submersible pumps. In addition to seal oil, some submersibles have an oil filled stator cavity. The oil in the stator cavity very efficiently transfers heat from the stator winding and core, and especially from the rotor, to the pump casing where convection carries it to the pumpage in which the pump is submerged. While the specifications for seal oil are fairly flexible, stator cavity oil has more constraints.

The slender dimensions of many pump shafts make them susceptible to distortion, which affects pump performance and reliability. This recording presents a methodical approach and effective techniques for measuring and correcting shafts which are bent or twisted.

Target audience: This presentation is intended for service center supervisors, managers and machine shop technicians.

Gene Vogel
EASA Pump & Vibration Specialist

Increasingly, it is not enough to just “fix” that pump. Customers want and need to understand the “why” behind the failure. This pump failure case study looks at:

• Failure methodology and how it was used
• The possible causes of failure
• The final analysis
• How the analysis impacted the repair approach

This presentation covers:

• Head & flow = volts & amps for pumps
• Testing pumps to their performance curves
• Troubleshooting pump performance
• What the pump curve tells you about cavitation 

This presentation covers: 

• What is classic pump cavitation?
• The NPSHA – NPSHR relationship
• How to identify the evidence of cavitation
• Other types of cavitation

By Gene Vogel
EASA Pump & Vibration Specialist

If you work with electric motors and pumps, you’ll eventually encounter a pump curve and one of its key parameters — best efficiency point (BEP). The BEP is the point on the curve where the pump operates most efficiently. Unique to each pump, the BEP is a product of both impeller design and several related pump curve parameters.

This article covers:

• Pump efficiency
• Effect of flow rate
• Effect of impeller design on BEP

READ THE FULL ARTICLE

Gene Vogel
EASA Pump & Vibration Specialist

When EASA adopted the slogan “The Electro-Mechanical Authority,” it was more than a superficial initiative. While electric motor repair is a core business for the vast majority of EASA service centers, rotating machinery of all types are a significant segment of service centers’ repair business and overall profitability. Next to electric motors, roto-dynamic pumps (centrifugal and axial flow pumps) are the largest single category of machines repaired in EASA service centers. The reasons for the expansion into the pump repair segment are clearly evident:

• Pumps are expensive machines and are not frequently built to standardized dimensions.Standard NEMA and IEC electric motors arecommodity items with little differentiation between manufacturers. But pumps aremuch less standardized. No standard framesizes exist for two of the most common style pumps – submersible pumps and vertical turbine pumps.
• In many applications, the heart of the pump,the impeller, is specially trimmed to match that application. Replacement requires longlead time, making repair a much more viable option.
• Major segments of pump applications aresecure during times of economic recession. Municipal water, wastewater and flood control have stable funding and demand.

EASA service centers looking for options for expansion, or to replace evaporating existing electric motor repair markets, have seen pump repair as a good fit. A majority of EASA service centers currently repair roto-dynamic pumps. Pumps are by far the largest category of machines driven by electric motors. 

If a service center is repairing electric motors, then it is almost certain that some of those motors are driving pumps, and the prospects for pump repair are its existing customers.

Gene Vogel
EASA Pump & Vibration Specialist

Most centrifugal pumps today have mechanical seals. However, those pumps that still use packing glands instead of mechanical seals require frequent maintenance and are more likely to show up in the service center for repair. The average mean time between failure (MTBF) for mechanical seals is about 7500 hours. Packing glands require packing replacement after about 1,000 hours of operation. And the shaft or shaft sleeve for packing gland pumps is subject to wear, so pump overhaul to repair the shaft or replace the sleeve is inevitable. Improper installation or adjustment of packing glands can greatly accelerate wear, making much more frequent repair necessary. Replacing packing is not a technically demanding task. However, there are some tips that will improve the performance of the packing, limit the energy usage and extend the MTBF. Attention to these details will allow service centers to provide quality repairs for their customers.

Bret McCormick
Stewart’s Electric Motor Works, Inc.

Split case pump seals are commonly the most difficult installation of any mechanical seal. The replacement of these seals usually is determined by the type originally found in the pump. The problem is that the existing seal type may not be the best for the fluid pumping application. The fluid to be pumped often is the last thing considered for a system designer specifying a pump for a general application. And if the fluid contains more than just water, problems can start to arise. Even closed recirculation systems have additives that can interfere with proper sealing.

For the purpose of terminology, when original equipment manufacturer (OEM) seals are mentioned we will be referring to “Single Spring Elastomeric Bellows” seals. 

A pump that has been worked on previously might even contain an improper seal. The seal may fit into the pump, but is the wrong working length or there might have been an improper selection of face materials. It might also have improper elastomers for the pumping application.

Common premature failures
Premature seal failure is generally described as any seal that does not run for an expected (and reasonable) length of time. Premature failure is not to be confused with catastrophic seal failure. That’s where a seal fails all at once, usually due to dry run conditions or breakup of the seal for mechanical reasons.  Keep in mind that these examples can happen in a matter of minutes, hours, or days and even months.  A successful installation is measured by the time in service between seal replacement.

Some of the most common premature failures of split case pumps with OEM seals in them will be: 

• Pumps that pass the hydrostatic test and then on startup will immediately leak.  
• Upon startup the seal isn’t leaking but in a short length of time will develop a drip that continues to get worse the longer the pump runs.  
• Installations that while the pump is running, the seals do not leak. They will leak when the pump shuts down; when the pump starts again the leak stops.

The factors you will want to consider to ensure the seals are installed correctly are:  cleanliness, proper set length (especially on pumps with locking collars), component handling, and material selection. The two most common mistakes during installation are hyperextension of the bellows (the elastomeric flexible component of the seal head) or the seal head itself being mounted on the shaft diagonally. The inherent complex design of the pump and the necessary steps required to assemble add to the challenge of proper installation.  Making sure that the head and seat mate as close to being perfectly parallel in whatever operational plane they function will lead to successful pump operation.

In most applications you can’t see the seal. So how do you determine proper installation? The answer to that: In many cases you really cannot. Only runtime will tell. Good installation practices have to be followed to best ensure that the seal will work properly.  It’s difficult to determine if the seals are installed properly until the pump is in operational mode.

Using correct seal type
One of the problems with replicating existing OEM seals that are installed in the pump is to make sure that they are the correct type of seal. Then you must determine if the seals are correct for that application. Knowing what makes up the fluid components of the pumpage will help you decide what materials the seal may include. For example, corrosive fluids, even chlorine, can shorten the life of the elastomer drastically. Suspended solids will find the small gap between the precision lapped mating faces to start leakage. It is important to remember when making the seal selection for the pump and application not to replicate someone else’s mistake by failing to consider all the parameters.

Even if the pump is hydrostatic tested in your service center, passes and does not leak, there will be times when the pump is installed and operational in the field and you will still experience premature seal failure.  

There will be occasions where an end user will separate the casings and only bring the rotating assembly in for recondition. Situations such as these are prime candidates for leakage after reassembly.  Your technicians are trained to ensure the shaft sleeves run true, the bearings are mounted properly, the seal components are carefully installed, the impeller is balanced…only to have the end user drop the assembly on the way back to the building.  The idea was to save time and money by not removing the entire pump.  If you have worked on split case pumps, then you have experienced one if not all of these premature failure issues at one time or the other. 

Cartridge seals
Most failure issues with OEM seals can be avoided by using cartridge seals. If the split case pump has enough clearance between the seal cage end of the stuffing box and the next obstruction, then a cartridge may be used.  Most of the problems associated with OEM seals may be eliminated because of the ease of installation of a cartridge seal.

The next obstruction, referred to as the down shaft restriction (DSR), almost always will be the bearing journals. If the space is there to accommodate the gland and locking collar outboard length of the seal, then a cartridge seal may be the best for your application. 

The reason a cartridge seal will outperform an OEM seal is because the set length of the seal and the proper alignment of the faces are built into the seal. The ease of installation and the elimination of possible seal failure and rework created by failure will offset the pricing difference between the OEM seal and a cartridge seal.

The proper face alignment and set length of any seal is paramount if you want longevity.  A cartridge seal in a stationary design will derive the face alignment from the centerline of the shaft. Conversely, a rotary design seal will derive the face alignment from the face of the seal cage or the way it is put onto the shaft.

The cartridge seal preload centering clips keep the faces of the cartridge seal together and in proper orbital alignment during the assembly process. The preload centering clips will also eliminate possible contamination of the faces.

The construction of the cartridge seal will allow you to assemble the rotating assembly and install the completed assembly into the pump housing without having to deal with all of the issues associated with movement that can occur and will affect the performance of OEM type seals.

After the pump is assembled, bolt the cartridge to the pump, place the set screws and pull the preload centering clips; you will know the seal is properly installed.

Cartridge seals create a reliable liquid seal between the pump housing and the pump shaft.  Pump speeds usually up to 3600 rpm create heat and wear from friction. The OEM seals are unbalanced and with increased face loads, will accelerate the wear. 

A cartridge seal is a balanced seal. Most cartridge seals in production today are double hydraulically balanced.  This is done internally in the cartridge seal and allows an offsetting force to lighten the face load of the primary sealing faces.  

When the face load is offset, then the seal will run cooler and will have better lubrication. This will extend the life of any seal. Lubrication is forced in between the seal faces by the process pressure. The more lubrication that is provided, the cooler the seal will run and the better the seal will perform.

Any seal must have adequate fluid between the faces for proper lubrication and operation. Should there be a period void of lubrication, the seal will burn up immediately. Dry running will destroy all seals.

A single cartridge seal, like any other, will contain the same components. The seal will contain primary lapped faces, one rotating and one stationary. The cartridge seal also has static and dynamic secondary components. They are usually o-rings to accomplish the total sealing of the pump unit.

Simplicity of putting a cartridge seal onto the shaft, assembling the rotating unit and then the assembling of the pump make it easy. After the assembly of the pump, all that is needed for completion is to fasten the cartridge seal by bolting the seal gland to the pump housing, setting the set screws and pulling the centering clips. Mounting the cartridge seal is simple.

Mechanical seals
Remember that mechanical seals are a tried, tested and a proven technology. Mechanical seals are the best way to create a reliable liquid seal. Also remember that any seal must be kept cool and lubricated by the fluid it pumps. 

Most seals don’t fail because they wear out. Running dry, vibration, cavitation, erosive fluids, contamination, and mechanical failures of shafts and bearings, all have detrimental effects on the life of the pump and its seals. 

All of these issues must be taken into consideration if you have a problematic sealing application with continual or premature failure. Identifying the mode of failure will be elusive at times. A lot can be determined by looking at the seal faces and components when you have seal failure. Most of the time a mode of failure can be determined by just looking at the seal components.  After correctly determining the mode of failure, you can select the proper seal for your application.

When you have a problematic application, your knowledge of selecting traditional mechanical seals and cartridge seals allows you to offer the customer corrective action and solutions to his mode of failure. The help provided by you from your analysis of the situation will demonstrate the value of your expertise and ensure return business.   

More on pump repair
If you want to learn more about pump maintenance and repair, I recommend that you attend EASA’s “Fundamentals of Pump Repair” seminar.

This presentation covers:

• Not enough pressure (head) or not enough flow – how do you respond?
• How to determine if a pump is operating properly
• Differentiating a pump problem from a system problem
• Determining pump load and power requirements
• The effect of fluid parameters and cavitation on pump performance. 

Target audience: This will be most useful for service center technicians and engineers. The content will also be beneficial for supervisors and managers who are responsible for pump failure analysis and testing. 

A leak rate of one drip per minute equals about a liter (quart) of water in three days. For an O-ring on a submersible pump, that is a major problem. O-rings are often used for static seals on submersible pumps. Understanding what makes a good static seal and what causes one to leak is important for pump maintenance and repair technicians.

The effectiveness of an O-ring static seal depends on the dimensions of the mating parts, the surface finish of the mating parts and the characteristics of the elastomeric O-ring. The focus of this article is the dimensions and condition of the mating parts.

Topics covered in the article include:

• Dimensions
• Identification of critical surfaces
• A case study

READ THE FULL ARTICLE

This presentation discusses:

• Potential savings for pump operations
• How service centers can profit
• Identifying system benefits

Target audience: This webinar will benefit service center technicians and supervisors. 

Por Gene Vogel
Especialista de Bombas & Vibraciones de EASA

Las bombas sumergibles pueden tener diferentes tipos de sensores o dispositivos de protección internos, los cuales pueden ser sensores de temperatura, transductores de vibración o sensores de humedad. Los sensores de temperatura y de vibración son idénticos a los utilizados en los motores no sumergibles, por lo que solo los sensores de humedad guardan especial relación con las bombas sumergibles. Es importante que los técnicos involucrados en la reparación de las bombas sumergibles sean conscientes de su presencia en cualquier bomba en los que se puedan encontrar y que comprendan como trabajan para asegurarse que funcionan correctamente después de terminar los trabajos de reparación.

Vertical turbine pumps are used extensively in every segment of industry. Although they are not complex, repairing them in the service center can present a few challenges. This presentation gives some approaches and procedures that experience has shown will make the job easier.

This presentation covers:

• Shaft material and specs
• Shaft coupling types
• Machining for shafts
• Bronze, plastic, graphite and cutlass bearing options
• Bearing clearance concerns and reference data 
• Bearing housing fits

Target audience: This webinar will benefit service center technicians and supervisors.

The rules of thumb often applied to journal bearings in horizontal machines don’t apply to vertical machines. Vertical turbine pumps are a common example.

This presentation explains the characteristics of bearings in these pumps and provide examples of manufacturers specifications.

In addition, specialty bearing materials will be discussed in regard to applications, specifications and installation.

Target audience: This webinar is most useful for service center technicians and engineers. The content is beneficial for supervisors and managers who are responsible for pump failure analysis and testing.

Gene Vogel
EASA Pump and Vibration Specialist

When motors are installed on top of vertical pumps, high vibration is a common problem. The source of the problem can be a mechanical issue with the pump, motor or coupling, or it can be hydraulic forces from the pump. Often structural issues involving resonance amplify the vibration. An understanding of the nature of this style pump and the various forces is essential to diagnosing and correcting vibration problems on vertical pump motors.

There are quite a number of configurations of vertical pumps. Submersible pumps fall into this general category. This discussion, however, will omit submersibles and focus on those pumps that are surface mounted where the motor is bolted to a pedestal on top of the pump. See Figure 1. This is the style that most commonly exhibits high vibration conditions. An important contributing condition is resonance, and specifically “reed frequency” resonance. But an understanding of the vibratory forces is important also.

When motors are installed on top of vertical pumps, high vibration is a common problem. The problem may be mechanical, hydraulic or structural.

This presentation provides an understanding of the nature of this style pump and the various forces essential to diagnosing and correcting vibration problems on vertical pump motors.

Gene Vogel
EASA Pump & Vibration Specialist

One of the most common repairs on centrifugal pumps is replacing worn or damaged wear rings. To restore efficient, reliable operation and prevent catastrophic pump failure, it is critical to restore proper clearances between the stationary casing wear ring and the rotating impeller wear ring. Although many pump manufacturers provide clearances and dimensions, some do not. There are plenty of aging pumps around from now-defunct manufacturers for which dimension data is simply not available.

In such cases, the rule of thumb that follows provides some guidance for acceptable running clearances, or the minimum running clearance chart in American Petroleum Institute (API) Standard 610 can be used as a guide.

• Suction side wear rings vs. rear wear rings
• Open vs closed impellers
• Wear ring clearances & specific speeds
• Wear ring clearance guide

READ THE FULL ARTICLE

Gene Vogel
EASA Pump & Vibration Specialist

One of the most common repairs on centrifugal pumps is replacing worn or damaged wear rings. For pumps with closed style impellers (impellers with a front shroud as described below), there will be a casing wear ring and possibly an impeller wear ring which is fitted to the outside diameter (OD) of the impeller suction eye. Impellers may also have rear wear rings which are important for controlling axial thrust. Pumps with open style impellers generally do not have suction eye wear ring clearance concerns, but they often have rear wear rings. The clearances between the stationary casing wear ring and the rotating impeller wear ring are critical to proper pump operation. Although many pump manufacturers will provide proper clearances and dimensions, some do not; there are plenty of old pumps around from now defunct manufacturers where dimension data is simply not available.

Gene Vogel 
EASA Pump and Vibration Specialist 

For most centrifugal pumps, the shaft has packing or a mechanical seal where the shaft enters the wet end. Fundamentally, a sealless pump sub­stitutes a magnetic drive for the shaft seal. The impeller shaft is fitted with a magnetic rotor which is contained in a thin metal cover. The shaft, impel­ler, the rotor and the bearings are all “wet” components; that is, they are completely submersed in whatever liquid is being pumped. Over the out­side of the magnetic rotor and cover is a magnetic drum which is driven by the power source, usually an elec­tric motor. The magnetic coupling between the rotor and drum delivers torque to the shaft and impeller. 

Gene Vogel 
EASA Pump and Vibration Specialist 

Most maintenance and operations personnel who work with centrifugal pumps have been warned to never start a pump unless it is primed. They have been warned that a pump that is started when loaded with air may cause the seal or packing to be scorched and permanently damaged, and that when the suction liquid level is below the pump (suction lift), the pump would not begin to pump. Then they encounter a pump that they are told is “self-priming,” and they begin to question if all that caution is neces­sary. So, what’s the real scoop on self-priming pumps? 

The fact is that no centrifugal pump is truly self-priming in suc­tion lift situations. And there actu­ally are several approaches where a pump may be started when loaded with air. First, though, in all cases the seal must be protected from overheating. 

Gene Vogel
EASA Pump & Vibration Specialist

Centrifugal pump failures are most commonly attributed to seal failure, impeller damage and bearing failures. A good understanding of failure modes for seals, impellers and bearings is essential to providing customers with reliable pump repairs. This presentation will explore various failure modes and provide some direction on ways to avoid them.  

• How mechanical pump seals operate, the importance of seal face material selection and proper installation techniques 
• Impeller damage examples and causes 
• General rolling element bearing failure modes 
• Bearing failure modes unique to vertical turbine pumps and associated vertical motors 

This recording will be useful for service center engineers, pump technicians and operations managers.

Gene Vogel
EASA Pump & Vibration Specialist

Submersible pumps may have any of several types of internal sensors or protective devices. These may include temperature sensors, vibration transducers or moisture sensors. The type of temperature and vibration devices are identical to those used in non-submersible style motors, so only the moisture sensors are of special interest regarding submersible pumps. It is important for technicians involved in the repair of submersible pumps to be aware of their presence in any specific pump they may encounter, and understand the manner in which they function to ensure they work properly after repairs are completed.