Chuck Yung 
EASA Technical Support Specialist 

The problem:  We recently rebuilt a 2-pole motor and the centrifugal blower it drives. When the customer reinstalled them, he reported high vibration levels.  Everything runs smoothly for 10-15 minutes after a cold startup. Then the vibration starts to climb. We balanced the rotor and blower to G 1.0 tolerances. We even balanced each of the 7 blower impellers separately using a balancing mandrel. Shaft runout was less than 0.0002" on the motor and blower when we finished the job. The customer uses laser alignment. He is convinced that us to rebuild the blower again. What did we do wrong?

Gene Vogel
EASA Pump & Vibration Specialist

Proper alignment of direct-coupled machinery is an essential element in reliability of a new or repaired machine (motor, pump, gear case, etc.). One common impediment to achieving proper alignment and smooth opera­tion is a “soft foot” condition. 

A soft foot occurs when all the feet of a machine case do not sit flat on the supporting base so that tightening the foot bolts causes distortion of the ma­chine case. The source of the soft foot could be a baseplate which is not flat or machine feet which are distorted. Not only does this make it difficult to align the machine, but the casing distortion may add additional load to the bearings and create internal mis­alignment between the rotating and stationary elements of the machine resulting in poor performance and increased vibration.

Chuck Yung 
EASA Technical Support Specialist 

When vibration problems occur, the magnitude and direction of the vi­bration can give a good indication of where to look for the cause. When vi­bration is higher in the vertical plane, one of the first things we should examine is the base/foundation of the motor. If the high vertical readings are compounded by indications of an eccentric airgap, such as high axial vibration and a predominant twice-line-frequency vibration, a “soft foot” or twisted frame is often to blame. 

Construction basics 
It is common practice for the align­ment technician to use prefabricated shims under the feet, sized to accept the hold-down bolt. The person perform­ing the alignment may not realize that a motor frame is not as solid as it appears. The fact that the foot itself might be over an inch (25 mm) thick, and the frame is cast iron or steel, causes the person to assume that it cannot distort. Nothing could be further from the truth. Because of that assumption, shims are often not placed to the greatest benefit. By understanding some construction basics, we can better place the shims to obtain the lowest vibration readings. 

Tom Bishop, P.E.
EASA Senior Technical Support Specialist

Occasionally an end user wants to take a motor designed for horizontal mounting and use it in a vertical position. In this article, we will address some of the key mechanical factors that should be considered when applying a horizontal ball bearing motor in a vertical mounting position. Figure 1 illustrates a horizontal motor in a vertical shaft down position.

These key factors include:

• Axial thrust load capacity of bearing supporting rotor weight
• Rotor weight
• Weight of output shaft attachments
• Axial thrust from direct connected driven equipment
• Bearing lubrication paths
• Bearing lubricant retention
• Shaft up or shaft down orientation
• Ingress protection
• Locking axial thrust bearing

Tom Bishop, P.E.
EASA Senior Technical Support Specialist

De vez en cuando un usuario final quiere utilizar un motor diseñado para montaje horizontal en posición vertical. En este artículo, trataremos algunos factores mecánicos clave que deben ser considerados cuando se utiliza un motor horizontal con rodamientos de bolas en una aplicación en la que trabaja en montaje vertical. La Figura 1 ilustra un motor horizontal en posición vertical con el eje hacia abajo.

Los factores clave incluyen:

• Capacidad de carga axial del rodamiento que soporta el peso del rotor.
• Peso del rotor
• Peso de los elementos acoplados al eje de salida
• Empuje axial de los equipos de impulsión acoplados directamente
• Trayectorias de lubricación de los rodamientos
• Retención del lubricante de los rodamientos
• Orientación del eje: Hacia abajo o hacia arriba
• Protección contra ingreso
• Fijación axial del rodamiento de empuje

Automatic alignment instruments are no substitute for the underlying process of aligning direct-coupled machines. This presentation explains the simple calculations that govern the alignment process. That understanding will allow technicians to use any alignment tool more effectively and deal with issues that confound the process.

En toda reparación mecánica, la capacidad para desmontar, reparar y volver a montar el motor de forma apropiada sin dañar innecesariamente ninguna de sus piezas es fundamental. Esto suena sencillo, sin embargo, durante el proceso de desarme se cometen demasiados errores costosos.

Si todos los motores entraran “como nuevos”, la tarea sería más simple, aunque esto no sería garantía de que el montaje del motor fuera adecuado.

Cuando un centro de servicio recibe un pago por reparar un equipo, quiere que este permanezca en funcionamiento, ya que, si el equipo falla dentro del período de garantía, deberá asumir el costo de volver a repararlo. Por lo que tiene sentido realizar la reparación correcta la primera vez.

Los procedimientos de reparación, así como los propios motores, son afectados por los cambios en la tecnología. Este libro intenta incluir las últimas tecnologías comprobadas. En muchos casos, los métodos de reparación tradicionales aún pueden ser la alternativa más práctica. Las opciones presentadas a lo largo de este libro están destinadas a ayudar a los técnicos a seleccionar el método de reparación correcto, reconociendo que la decisión final recae en el propietario del equipo.

Algunas veces los métodos de reparación pierden popularidad, no porque aparezcan métodos mejores sino debido a técnicas deficientes. Otros métodos de reparación son adecuados para algunas aplicaciones, pero no para otras. Es trabajo del reparador decidir cuál será el mejor método para cada caso.

Este libro se encuentra dividido en secciones para los componentes básicos del motor con métodos de reparación y consejos dispersos por todas partes. Donde resulte práctico, se discuten también las causas de fallo. Esto ayudará a los técnicos a seleccionar el método de reparación más apropiado para cada aplicación en particular. La información presentada se basa en publicaciones de EASA y en revistas técnicas y literatura suministrada por fabricantes de motores, proveedores y centros de servicio establecidos.

COMPRAR DESCARGAR COMPRAR VERSIÓN IMPRESA

Tabla de contenido

• Terminología del motor
• Aplicaciones del motor y encerramientos
• Procedimientos de inspección y prueba
• Consejos para desmontar motores
• Rodamientos
• Alojamientos de rodamientos, orificios de eje, sellos y ajustes
• Ejes
• Rotores
• Ensamble del motor
• Accesorios y cajas de conexiones del motor
• Dinámica del motor
• Vibración y geometría del motor
• Corrientes por el eje/rodamientos
• Consideraciones especiales para motores a prueba de explosión
• Fallos en las componentes mecánicas
• Reparaciones misceláneas

Esta obra contiene muchas sugerencias sobre el manejo apropiado de las diferentes partes de un motor para minimizar los daños durante el proceso de reparación. Sin embargo, es imposible desarrollar un listado que las incluya todas.

En cambio, el principio básico de tomarse el tiempo para usar la herramienta adecuada y por lo general el procedimiento apropiado guiará a los técnicos por el camino correcto.

This 40-page booklet provides a great marketing tool for your service center! Use it to provide end users with information that will help them obtain the longest, most efficient and cost-effective operation from general and definite purpose electric motors with these characteristics:                                                                                                          

• Three-phase, squirrel-cage induction motors manufactured to NEMA MG 1 standards 
• Power ratings from 1 to 500 hp (1 to 375 kW)                                        
• Speeds of 900 to 3600 rpm (8 to 2 poles) 
• Voltages up to 1000V, 50/60 Hz 
• All standard enclosures (i.e., DP, TEFC, WPI, WPII) 
• Rolling element (ball and roller) and sleeve bearings

This booklet covers topics such as:

• Installation, startup and baseline information
  • Basic system considerations
  • Installation
  • Startup procedures
  • Baseline data
  • Total motor management
• Operational monitoring and maintenance
  • Application specific considerations
  • Preventive, predictive and reliability-based maintenance
  • Inspection and testing
  • Relubrication of bearings
• Motor and baseline installation data
• How to read a motor nameplate
  • Overview
  • Required information
  • Other terms
• Motor storage recommendations
  • Motor storage basics
  • Preparation for storage
  • Periodic maintenance

This resource is provided as a FREE download (use the link below). You can also purchase printed copies ready to distribute to your current or potential new customers. The cover of this booklet can also be imprinted with your company's logo and contact information (minimum order or 200). Contact EASA Customer Service for details.

READ MORE ABOUT THE FEATURES AND BENEFITS

Por Gene Vogel
Especialista de Bombas y Vibraciones de EASA

Realizar una correcta alineación de las máquinas acopladas de forma directa es un elemento esencial para garantizar la confiabilidad de operación de una máquina nueva o reparada (motor, bomba, caja de engranajes, etc.). Uno de los impedimentos comunes para lograr una alineación adecuada y un correcto funcionamiento, es el denominado  "pie suave".

DESCRIPTION
This 94-page handbook (3.5" x 6", 9cm x 15cm) contains carefully selected materials designed to assist repair firms in their everyday work. Just as important, your customers and potential customers can use this pocket handbook as a handy reference for mechanical data for motors and driven equipment. Buy this great resource as is OR custom brand your company logo and information on the cover to turn it into a great marketing piece for your salespeople!

BUY COPIES OF THIS HANDBOOK

TABLE OF CONTENTS

Alignment
Alignment Information
Suggested Alignment Tolerances
ANSI/ASA Alignment Quality

Balancing And Vibration
Single-Plane Versus Two-Plane Balancing
Vibration Tests
Unfiltered Housing Vibration Limits
FFT Vibration Analysis
Vibration Constants
Vibration Conversion Factors
Electric Motor Vibration Diagnostic Chart

Motor Application Forumlas
Output
Shear Stress
Speed–AC Machinery 
Affinity Laws–Centrifugal Applications

Conversion Factors, Equivalencies & Formulas
Conversion Factors
Temperature Conversion Chart
Common Fractions Of An Inch–Decimal & Metric Equivalents
Prefixes–Metric System
Formulas For Circles

Bearings
Nominal Dimensions For Radial Ball Bearings
Nominal Dimensions For Cylindrical Roller Bearings
Radial Ball Bearing Fit Tolerances
Cylindrical Roller Bearing Fit Tolerances
Lock Nuts And Lock Washers For Ball Bearings

Motor Bearing Lubrication
Lubricating Oil Viscosity Conversions
NLGI Grease Compatibility Chart
Grease Classifications
Grease Relubrication Intervals

Metals And Alloys
Properties Of Metals And Alloys
Weight Formulas For Steel
Thermal Linear Expansion

Bolts
ASTM And SAE Grade Markings For Steel Bolts And Screws
Precautions For Tightening Bolted Joints
Bolt Tightening Torque Values
Tap Drills And Clearance Drills For Machine Screws

Keys And Keyseats
NEMA Keyseat Dimensions–Foot-Mounted AC & DC Machines
IEC Shaft Extension, Key And Keyseat (Keyway) Dimensions
Square And Flat Stock Keys
Standard Keyseat Sizes
Metric Keys–Standard Sizes

Belts And Sheaves
Pulley Formulas For Calculating Diameters and Speeds
Belt Installation
Belt Tensioning
Belt Deflection Force And Elongation Ratio
Standard V-Belt Profiles And Dimensions
V-Belt Sheave Dimensions
V-Belt Sheave Dimensions For AC Motors With Rolling Bearings
Application Of V-Belt Sheave Dimensions To AC Motors With Rolling Bearings
Mounting Of Pulleys, Sheaves, Sprockets, And Gears On Motor Shafts
Minimum Pitch Diameter For Drives Other Than V-Belts

Welding, Brazing And Soldering
Recommended Copper Welding Cable Sizes
Types Of Weld Joints 
Brazing
Basic Joints For Brazing
Soldering
Melting Temperatures Of Tin-Lead-Antimony Alloys
Flux Requirements For Metals, Alloys And Coatings

Slings, Wire Rope, Shackles and eyebolts
Types Of Slings
Typical Sling Hitches
Wire Rope
Spreader Bars
Lifting Capacity
Forged Shackles
Eyebolt Strength

Common Signals For Crane

Gene Vogel
EASA Pump & Vibration Specialist

Shaft alignment is a critical step in the installation of rotating machinery, in a new installation or a repaired machine. Skipping or botching this step can decrease operating efficiency and shorten machine life. The procedure for aligning two rotating machines requires measuring their relative shaft positions and adjusting one or both machine cases, usually by shimming at the feet. Until recently, though, how closely the shafts need to be aligned was an open question. That changed with the publication of American National Standards Institute/Acoustical Society of America (ANSI/ASA) standard 2.75-17. Here is a summary of what it covers and how it will benefit users involved with shaft machinery alignment.

• The need for a standard
• Purpose and scope
• Tolerances
• Alignment principles
• Alignment quality grades
• Making machine moves

READ THE FULL ARTICLE

​Este folleto de 40 páginas ofrece una gran herramienta de marketing para su centro de servicio! Lo utilizan para proporcionar a los usuarios finales con información que le ayudará a obtener la, operación más eficiente y rentable de propósito más larga de los motores eléctricos generales y definidas con estas características:

• Trifásica, motores de inducción de jaula de ardilla fabricados con las normas NEMA MG 1
• Los valores de potencia de 1 a 500 CV (1 - 375 kW)
• Velocidades de 900 a 3600 rpm (8 a 2 polos)
• Tensiones de hasta 1000 V, 50/60 Hz
• Todas las cajas estándar (es decir, DP, TEFC, WPI, WPII)
• Rodando elemento (bolas y ruedas) y los cojinetes de manguito

Este folleto cubre temas tales como:

• Instalación, puesta en marcha y la información de base
• monitoreo y mantenimiento operativo
• Datos del motor y la instalación de línea de base
• Cómo leer una placa de identificación del motor
• recomendaciones de almacenamiento del motor

Este recurso se ofrece como una descarga gratuita (utilizar el enlace más abajo). También puede comprar copias impresas listo para distribuir a sus actuales o potenciales nuevos clientes. La portada de este folleto también se puede imprimir con el logotipo e información de contacto de su empresa (pedido mínimo o 200). Póngase en contacto con Servicio al Cliente EASA para más detalles.

Gene Vogel
Pump & Vibration Specialist
EASA
St. Louis, MO

The paper "Overview of the New Shaft Alignment Standard" by Gene Vogel, presented at the EASA Convention 2018, introduces the ANSI ASA S275 Part 1: General Principles, Methods, Practices, and Tolerances standard for shaft alignment. This standard was developed by the Vibration Institute in collaboration with the Acoustic Society of America (ASA) to provide a comprehensive and consistent approach to shaft alignment across various industries. Prior to this, there was no national or international standard for shaft alignment, leading to inconsistencies in methodologies and tolerances.

The standard focuses on machine configurations commonly found across industries, specifically "4 bearing sets," which consist of two independent shafts each supported by a pair of bearings and coupled by a flexible coupling. Examples include horizontal motor-pump or motor-fan combinations. The intention is to expand this initial document with additional standards addressing other machine configurations, such as vertical machines and 3 bearing sets.

The standard provides guidelines on shaft alignment tolerances, base flatness and level, shaft runout, coupling runout, pipe and conduit strain, soft foot, and offline-to-running (OLTR) machinery movement. It emphasizes the importance of turning both shafts when making alignment measurements to ensure accuracy. Tolerances for pipe and conduit strain are set to prevent changes in shaft alignment greater than 50 micrometers (2 mils) vertically or horizontally at the coupling.

A holistic approach to the shaft alignment process is presented, including a flow chart documenting key steps and decision points. The standard includes informative annexes covering alignment principles, machine move calculation formulas, identifying and correcting pipe strain, OLTR methods, laser detector systems, graphic alignment modeling, repeatability, and an alignment and machinery installation checklist.

Alignment principles are explained through two common methods: offset and angularity between shaft centerlines, and flex plane angles at the coupling mechanical link (CML). The flex plane angles more accurately represent the work done by the coupling and are used to establish alignment tolerances. Alignment Quality Grades are provided based on flex plane angles and machine operating speed, with three grades: AL4.5 (Minimal), AL2.2 (Acceptable), and AL1.2 (Excellent).

The standard also addresses practical concerns related to moving machine cases, such as soft foot, base-bound, and bolt-bound conditions. It provides guidelines for controlled machine positioning and emphasizes the importance of proper axial spacing (coupling gap).

Several annexes offer detailed instructions on related topics. Annex B covers correction move formulas for various dial indicator setups. Annex D explains OLTR movement and how to establish target values for alignment. Annex F discusses alignment modeling, which helps visualize and calculate machine case moves. Annex H provides a machinery installation checklist to ensure important steps are not missed.

Key Points Covered:

• Development and scope of the ANSI ASA S275 Part 1 standard
• Focus on "4 bearing sets" machine configurations
• Guidelines on shaft alignment tolerances and related factors
• Holistic approach to the shaft alignment process
• Alignment principles and methods
• Alignment Quality Grades based on flex plane angles and machine speed
• Practical concerns related to moving machine cases
• Detailed instructions in annexes on correction moves, OLTR movement, alignment modeling, and installation checklist

Key Takeaways:

• The new standard provides a consistent approach to shaft alignment across industries.
• Focus on common machine configurations with plans to expand to other setups.
• Emphasis on accurate alignment measurements and tolerances.
• Holistic approach includes flow charts and detailed annexes.
• Flex plane angles are used to establish alignment tolerances.
• Alignment Quality Grades help determine acceptable alignment based on machine speed.
• Practical guidelines for moving machine cases and addressing alignment issues.
• Comprehensive annexes offer valuable instructions for various aspects of shaft alignment.

Ken Gralow
Gray Electric Co.
Schenectady, New York
Technical Education Committee Member

Shaft couplings are devices that connect two rotating shafts together. They efficiently transfer motion and power from the drive unit to the driven unit without adversely impacting either piece of rotating equipment. Under ideal conditions, both shafts should function as a continuous unit.

The design of a flexible coupling is to accommodate small amounts of shaft misalignment. Coupling manufacturers have designed their couplings to withstand the forces resulting from excessive shaft misalignment. Unfortunately, shaft alignment tolerances have sometimes been governed by the coupling manufacturers’design speecifications. These are maximum values that are dimensionally possible for a specific coupling. The coupling misalignment tolerances reported by coupling manufacturers apply ONLY to the coupling.

Tom Bishop, P.E.
EASA Senior Technical Support Specialist

We often hear the terms preventive maintenance (PM) and predictive maintenance (PdM) of electric motors. However, it’s far less often that we give consideration to the tasks associated with these methods of maintaining motor operation and extending operating service life. This article will address some of the more common activities associated with PM and PdM, with the focus on three-phase squirrel cage motors.

Las versiones impresas y en forma de descarga del valioso manual didáctico / recurso de EASA, “Principios de Motores C.A. Medianos y Grandes”, se encuentran ahora disponibles en inglés y en español. El manual incluye gráficos e ilustraciones, fotografías y mucha información técnica sobre máquinas C.A., incluyendo como funcionan, información específica sobre los tipos de encerramientos, fabricación de componentes y aplicaciones.  Muchos de los principios incluidos en el libro aplican a todos los motores C.A., especialmente a aquellos accesorios que fueron asociados en el pasado con las máquinas más grandes (como encoders, RTDs, termostatos, calentadores de espacio, sensores de vibración, etc.).

Las versiones  forma de descarga ofrecen funciones prácticas ya que contienen toda la información que contiene el manual impreso, pero en formato PDF, fácil de usa, ya que contiene marcadores que permiten a los lectores navegar rápidamente por el documento y “saltar” a la página deseada.

Las secciones del manual incluyen:

• Terminología y Definiciones del Motor
• Tipos de Encerramientos de Motores
• Aplicaciones Típicas para Motores
• Consideraciones de Manejo y Seguridad
• Teoría Básica del Motor
• Normas para Motores
• Estatores
• Rotores de Jaula de Ardilla
• Ejes
• Lubricación y Rodamientos
• Accesorios del motor & Cajas de Conexiones
• Procedimientos de Inspección y Prueba
• Alineamiento del Motor, Vibración y Ruido
• Procedimientos de Almacenamiento
• Máquinas Sincrónicas

COMPRAR

This version of Principles of Medium & Large AC Motors manual is now available to address applicable IEC standards and practices. This 360-page manual was developed by industry experts in Europe along with EASA's engineering team. (The "original" version of this book based on NEMA standards remains available as a separate document.)

This manual includes drawings, photos and extensive text and documentation on AC motors, including how they work, information on enclosures, construction on components and applications. Many of the principles included apply to all AC motors, especially those with accessories that are associated with larger machines in the past (such as encoders, RTDs, thermostats, space heaters and vibration sensors).

While the manual covers horizontal and vertical squirrel-cage induction motors in the 37 to 3,700 kW (300 to 5,000 hp) range, low- and medium-voltage, most of the principles covered apply to other sizes as well. 

This valuable instructional/resource manual is available in printed and downloadable versions, and focuses primarily on IEC motors.

Sections in the manual include:
(Download the PDF below for the complete Tables of Contents)

• Motor nomenclature & definitions
• Motor enclosures
• Typical motor applications
• Safety & handling considerations
• Basic motor theory
• Motor standards
• Stators
• Squirrel cage rotors
• Shafts
• Bearings & lubrication
• Motor accessories & terminal boxes
• Test & inspection procedures
• Motor alignment, vibration & noise
• Storage procedures
• Synchronous machines

BUY A COPY FOR YOUR OFFICE

PRINTED BOOK DOWNLOADABLE PDF

This book is also available focusing on NEMA Standards — in both English and Español.

NEMA - English NEMA - Español

This valuable instructional/resource manual is available in printed, downloadable and CD-ROM versions.

For this second edition, this 320-page manual has been reorganized, updated with new information, including revised standards and published articles, and edited extensively. The manual includes drawings, photos and extensive text and documentation on AC motors, including how they work, specific information on enclosures, construction of components and applications. Many of the principles included apply to all AC motors, especially those with accessories that were associated with larger machines in the past (such as encoders, RTDs, thermostats, space heaters, vibration sensors, etc.).

While the manual covers horizontal and vertical squirrel-cage induction motors in the 300 to 5,000 horsepower range, low- and medium-voltage, most of the principles covered apply to other sizes as well.

This manual focuses primarily on NEMA motors.

Sections in the manual include:

• Motor nomenclature & definitions
• Motor enclosures
• Typical motor applications
• Safety & handling considerations
• Basic motor theory
• Motor standards
• Stators
• Squirrel cage rotors
• Shafts
• Bearings & lubrication
• Motor accessories & terminal boxes
• Test & inspection procedures
• Motor alignment, vibration & noise
• Storage procedures
• Synchronous machines

BUY NOW

BOOK DOWNLOAD CD-ROM BOOK & CD-ROM

This book is also available focusing on IEC Standards ... IEC VERSION

 

This book was developed to help electric motor technicians and engineers prevent repeated failures because the root cause of failure was never determined. There are numerous reasons for not pursuing the actual cause of failure including:

• A lack of time.
• Failure to understand the total cost.
• A lack of experience.
• A lack of useful facts needed to determine the root cause.

The purpose of this book is to address the lack of experience in identifying the root cause of motor failures. By using a proven methodology combined with extensive lists of known causes of failures, one can identify the actual cause of failure without being an “industry expert.” In fact, when properly used,  this material will polish one’s diagnostic skills that would qualify one as an industry expert.

The book is divided into the various components of an electric motor. In addition to a brief explanation of the function of each component and the stresses that act upon them, numerous examples of the most common causes of failure are also presented.

For this second edition, the manual has been reorganized and updated with new information including a new approach to methodology, new case studies and a new section covering synchronous machine failures. This could not have been done without many contributions from EASA members and the Technical Education Committee. 

The all new “Root Cause Methodology” section goes into great detail explaining that effective root cause failure analysis must take place within the context of a practical problem-solving methodology or framework. It covers a modified Plan-Do-Check-Act process that emphasizes the importance of planning and the related problem-solving methodology components. This section also explains A3, a high-level reporting tool that is very effective for problem solving.

In addition, besides a systematic approach to problem solving, root cause failure analysis of motors and motor systems requires familiarity with contributing factors attributable to various kinds of applications, environments and industries. This includes how various stresses can affect motor components and the reciprocal impact the motor system may have on the motor. This section includes a table with a detailed summary of motor stresses. 

There also is a new section on “Synchronous Machine Failures” and an expanded “Case Studies” section. Readers are guided through eight case studies.

With 328 pages, the book provides extensive information, including a wide range of failures, the likely causes listed, and the methodology for confirming the probable cause of each failure. 

Members may purchase a printed manual and/or a PDF download. The printed manual is in black and white, while the download shows most of the failure photos in color.  

Sections in the manual include:

• Root Cause Methodology (all new)
• Bearing Failures
• Stator Failures
• Shaft Failures
• Rotor Failures
• Mechanical Failures
• DC Motor Failures
• Synchronous Machine Failures (all new)
• Accessory Failures
• Case Studies (expanded)
• References

This book is available as part of EASA's Root Cause Failure Analysis seminar.

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PRINTED COLOR BOOK DOWNLOADABLE PDF PRINTED COLOR BOOK & PDF

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DISCOUNTED BLACK & WHITE BOOKS!
Prices are now DISCOUNTED on remaining black & white books while supplies last! If you have already purchased a black & white manual and are interested in the color version, please contact EASA Customer Service (+1 314 993 2220).

B&W BOOK B&W BOOK & DOWNLOAD

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This webinar recording provies a straightforward look at the simple relationship between shaft centerlines that is known as shaft alignment. Bypassing the common discussion of laser and manual instruments, this presentation gets to the heart of the shaft alignment process. Topics covered will include:

• Fundamental concepts
• How to visualize machine case position
• Practical solutions for moving machine cases
• Applying tolerances
• The foot-base-foundation connection

Gene Vogel
Pump & Vibration Specialist
Electrical Apparatus Service Association
St. Louis, MO

The paper "Shaft Alignment: Rock ’N’ Roll Machinery Style" by Gene Vogel, presented at the EASA Convention 2015, delves into the intricacies of shaft alignment in industrial machinery. Vogel emphasizes that while technicians often learn shaft alignment as a procedural task, a deeper understanding of the relationship between shaft centerlines and their response to alignment moves is crucial for handling unexpected situations in industrial environments.

The paper begins by discussing the fundamental concept of misalignment, explaining that shaft centerlines can be coincident, parallel, or skew. The most general case is skew centerlines that do not intersect, which becomes the defining case for alignment. Vogel explains that the severity of misalignment is determined by the angle between the spool centerline and the shaft centerlines at the flex planes. This angle is crucial for understanding alignment tolerances.

Vogel then transitions to visualizing misalignment in vertical and horizontal planes, using an XYZ coordinate system. He explains that offset and angularity in these planes are described by the intersection lines of the vertical planes containing the shaft centerlines with a horizontal plane. The paper provides a detailed example of calculating offset and angularity, illustrating how to determine the necessary correction moves.

The paper also addresses the challenges of aligning machines with base-bound or bolt-bound conditions, where both machines need to be moved to achieve proper alignment. Vogel explains how to calculate the required moves by drawing a zero line that minimizes the moves and avoids limiting bounds.

Tolerances are discussed in the context of limiting the angle between the shaft centerline and the spool centerline. Vogel explains that the objective of shaft alignment is to reduce vibratory forces to an acceptable level. He provides examples of alignment tolerances published by alignment tool vendors and industry experts.

The concept of target values is introduced, emphasizing the importance of aligning the centerlines to an offset position to account for thermal growth, torque strains, and piping strains. Vogel explains the OL2R (off-line to running) measurement process, which involves measuring the change in position from cold, off-line conditions to normal operating conditions.

The paper concludes with practical advice on moving the machine cases and addressing soft foot conditions. Vogel highlights the importance of ensuring that the machine is stable and free from soft foot conditions, which can affect alignment and machine reliability. He also emphasizes the need for proper training on alignment tools and understanding the alignment process beyond just using the tools.

Key Points Covered:

• Fundamental concept of misalignment and shaft centerlines
• Visualizing misalignment in vertical and horizontal planes
• Calculating offset and angularity for alignment corrections
• Addressing base-bound and bolt-bound conditions
• Understanding alignment tolerances and their importance
• Using target values to account for thermal growth and other strains
• Practical advice on moving machine cases and addressing soft foot conditions

Key Takeaways:

• A deeper understanding of shaft alignment is crucial for handling unexpected situations in industrial environments.
• Misalignment severity is determined by the angle between the spool centerline and the shaft centerlines at the flex planes.
• Visualizing misalignment in vertical and horizontal planes helps in understanding and correcting alignment.
• Properly addressing base-bound and bolt-bound conditions is essential for achieving alignment.
• Alignment tolerances are important for reducing vibratory forces to acceptable levels.
• Using target values helps in aligning machines to account for thermal growth and other operational strains.
• Ensuring machine stability and addressing soft foot conditions are critical for successful alignment and machine reliability.

Matthew Conville, MBA, PE
EASA Technical Support Specialist

Balancing plant maintenance costs and activities with the need to achieve production goals is a daily challenge for most maintenance professionals. Since the motor-driven system is often a critical component in this dynamic, let’s look at some best practices to help it achieve those goals and meet customer demands.

To plant maintenance pros in most industries, these are familiar questions:

• “How do we improve reliability within our plant?”
• “How can we reduce unplanned downtime, so our production stays more consistent?”
• “How can we decrease our total cost of ownership of our equipment?”

They phrase it differently, but ultimately each of these questions is about improving the efficiency and reliability of the motor-driven system. Although that encompasses a wide range of components including fans, pumps, and drives, here we’ll focus on the electric motors.

READ THE FULL ARTICLE

Austin Bonnett
EASA Education and Technology Consultant
Gallatin, MO

In the paper "The Most Unlucky Things That Can Happen To A Customer’s Motor," presented at the EASA Convention 2004, Austin Bonnett explores the common causes of motor failures and provides insights into how these failures can be predicted, prevented, and repaired. The paper emphasizes the importance of understanding the root causes of motor failures, which are often predictable, repeatable, and preventable.

Bonnett outlines a methodology for identifying the root causes of motor failures, which includes examining the failure mode, failure pattern, appearance, application, and maintenance history. He stresses the importance of recording critical data and measuring results to benchmark performance and make necessary upgrades or revisions.

The paper identifies the most common sources of motor problems, including issues with bearings, stators, rotor cores, shafts, misalignment, and other factors. Bearing problems are often caused by improper lubrication, contamination, and excessive vibration and shock. Improper lubrication can result from using too much or too little lubricant, incompatibility of lubricants, or using the wrong type of lubricant. Contamination can occur due to moisture, foreign materials, and corrosion, leading to bearing damage. Excessive vibration and shock can be caused by rotor unbalance, coupling unbalance, system unbalance, sudden stops or loading, and environmental influences.

Stator problems are typically related to thermal overload, severe electrical abnormalities, and contamination of the insulation system. Thermal overload can result from horsepower overload, excessive ambient temperatures, load cycling, too many starts, or failure to accelerate. Electrical abnormalities include overvoltage, undervoltage, unbalanced voltage, single phasing, transients, and partial discharge. Contamination of the insulation system can be caused by moisture, condensation, abrasion, and foreign materials.

Rotor core failures are often due to poor geometry, out of balance, defective or damaged squirrel cages, and improper joining of bars to end rings. Common shaft failures include metal fatigue, rotational bending, torsional bending, extreme temperatures, residual stress, and environmental factors. Misalignment issues can arise from problems with the motor, coupling, driven equipment, mounting base, and other factors.

Bonnett also discusses other frequent causes of motor failures, such as misapplication, misuse, inappropriate repairs, alteration of the cooling system, hazardous terminal boxes, and coupling failures. He emphasizes the importance of proper maintenance and monitoring to prevent these failures and ensure reliable motor operation.

Key Points Covered:

• Root cause methodology for identifying motor failures
• Common sources of motor problems, including bearings, stators, rotor cores, shafts, and misalignment
• Causes of bearing problems, such as improper lubrication, contamination, and excessive vibration and shock
• Stator problems related to thermal overload, electrical abnormalities, and contamination
• Rotor core failures due to poor geometry, defective squirrel cages, and improper joining of bars to end rings
• Common shaft failures, including metal fatigue, rotational bending, torsional bending, and residual stress
• Misalignment issues and other frequent causes of motor failures

Key Takeaways:

• Motor failures are often predictable, repeatable, and preventable.
• Understanding the root causes of motor failures is essential for effective troubleshooting and repair.
• Proper lubrication, contamination prevention, and vibration control are crucial for bearing health.
• Thermal overload, electrical abnormalities, and contamination are common causes of stator problems.
• Rotor core failures can result from poor geometry, defective squirrel cages, and improper joining of bars to end rings.
• Shaft failures are often due to metal fatigue, rotational bending, torsional bending, and residual stress.
• Misalignment and other factors can lead to motor failures, emphasizing the importance of proper maintenance and monitoring.

 

Jim Bryan
EASA Technical Support Specialist

End play in an electric motor is the amount of axial movement allowed by the motor’s construction. This end play is limited by the motor’s bearing design. The bearing’s primary purpose is to locate the shaft radially so it can be aligned to the driven equipment shaft and efficiently transmit torque to the load. It is also important that the axial location be controlled such that the motor and driven equipment bearings are not subjected to excessive thrust or vibration and still have room for thermal growth of the shaft as it heats up during operation.

This can be accomplished by a number of ways depending on the design of the motor. If the motor has sleeve bearings, axial movement is expected within the limits of the bearing design.  Most rolling element bearings have much less axial clearance but must be contained in the bearing housing to control the end play.

Tom Bishop, P.E.
EASA Senior Technical Support Specialist

Two common scenarios that service centers deal with regarding belt drive applications are failure of a motor drive end ball bearing or breakage of the shaft at the drive end bearing shoulder. The cause of these failures often is over-tensioning of the v-belts. However, there are many other faults or undesirable practices that can lead to premature bearing failure, belt wear and sheave wear. 

Due to practical space limitations, this article won’t be exhaustive in its coverage but will deal with common scenarios other than motor bearing failure and shaft breakage.

9 presentations

$45 for EASA members

 

A special discounted collection of 9 webinar recordings focusing on a wide variety of vibration, balancing and alignment topics.

Once purchased, all 9 recordings will be available on your "Downloadable products purchased" page in your online account.

Downloadable recordings in this bundle include:

An Overview of Vibration Tolerances
Presented August 2019

When it comes to machine vibration, “how much is too much” depends on a number of factors. Knowing which standard and/or tolerance applies requires a working knowledge of the standards and some basics of vibration terminology. This  presentation provides an overview of where and how NEMA, IEC, ISO and Hydraulic Institute standards may apply to machines commonly encountered in EASA service centers.

• NEMA, IEC, ISO and Hydraulic Institute standards
• Basic vibration terminology
• What standard applies?

Target audience: Service center managers, engineers, in-shop and field service technicians can benefit from a clearer understanding of vibration standards and terminology.

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Basics of Machinery Foundations and Bases
Presented November 2012

A faulty machine foundation or base can lead to excessive vibration and premature failure. This presentation explains the fundamentals of machinery foundation construction and how to identify and troubleshoot machine base problems, including basic vibration techniques and ODS analysis.

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Fundamentals of Shaft Alignment
Presented November 2012

Automatic alignment instruments are no substitute for the underlying process of aligning direct-coupled machines. This presentation explains the simple calculations that govern the alignment process. That understanding will allow technicians to use any alignment tool more effectively and deal with issues that confound the process.

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Shaft Alignment
Presented March 2016

This webinar recording provies a straightforward look at the simple relationship between shaft centerlines that is known as shaft alignment. Bypassing the common discussion of laser and manual instruments, this presentation gets to the heart of the shaft alignment process. Topics covered will include:

• Fundamental concepts
• How to visualize machine case position
• Practical solutions for moving machine cases
• Applying tolerances
• The foot-base-foundation connection

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ANSI's New Shaft Alignment Standard
Presented July 2018

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. 

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How to Balance Overhung Fans
Presented October 2011

Often an overhung fan is balanced in a single plane, only to find that the vibration has shifted to the outboard bearing. Attempts to use standard two-plane techniques may result in calculated correction weights that are very large and produce poor results. There are more effective ways to approach this common problem. This presentation shows a methodical approach and techniques for tackling this difficult balancing problem.

Target audience: This presentation is intended for field service balancing technicians, supervisors and managers.

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Vibration on Belt Driven Machines
Presented June 2013

This presentation focuses on:

• Identifying belt vibration
• Identifying pulley pitch line run-out vibration
• Other vibration sources
• ODS analysis

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The FFT (aka Spectrum): What It Is and Ways to Use It
Presented July 2012

This presentation examines:

• How the spectrum is generated from the vibration signal
• The effect of f-max ad resolution settings
• Averaging techniques
• Scaling and demodulation

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Vibration Problems on Vertical Motors and Pumps
Presented December 2010

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.