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Articles in industry publications

Vibration and Alignment

  • April 2020
  • Number of views: 479
Webinar recording bundle

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

Just $45 for EASA members!

Principles of Medium & Large AC Motors, 1st Edition - IEC

  • February 2020
  • Number of views: 1728
Book

This 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 IEC motors and standards.

An Overview of Vibration Tolerances

  • August 2019
  • Number of views: 280
Webinar recording

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.

Principios de Motores C.A. Medianos y Grandes - NEMA

  • February 2019
  • Number of views: 894
Book

Las versiones impresas, en CD-ROM y en forma de descarga del valioso manual didáctico / recurso de EASA, “Principios de Motores C.A. Medianos y Grandes”, se  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.).

Techniques for detailed screening of vibration data; setting alarm limits

  • January 2018
  • Number of views: 816
Article

Many EASA service centers conduct vibration-based machine condition monitoring programs for their customers. This is a valuable revenue source that aligns the service center as a team member with the customer to provide uptime on their machinery and control maintenance costs. It also puts some of the responsibility for predicting machine failures on service center personnel who may be managing vibration data for hundreds of machines in multiple customer facilities. Given that vibration data is complex, composed of amplitude, frequency and phase, that can be a daunting task.

Técnicas para el filtrado detallado de datos de vibración-Estableciendo los límites de alarma

  • January 2018
  • Number of views: 567
Article

Muchos centros de servicio llevan a cabo programas de monitoreo por condición basado en la vibración de las máquinas para sus clientes. Esta es una fuente valiosa de ingresos que integra al centro de servicio como miembro del equipo del cliente para garantizar el tiempo de funcionamiento de su maquinaria y controlar los costos de mantenimiento. Esto también pone parte de la responsabilidad de predecir fallos en las máquinas, en el personal del centro de servicio que puede estar gestionando los datos de vibración para cientos de máquinas en múltiples instalaciones del cliente. Dado que los datos de vibración compuestos por amplitud, frecuencia y fase son complejos, esta puede ser una ardua tarea.

Applying balance tolerances to various machine rotors

  • August 2017
  • Number of views: 773
Article

The ISO balancing specification for rigid rotors (ISO 1940-1) was innovative when it was introduced decades ago. It established Balance Quality Grades based on the theoretical velocity the mass center of gravity of a rotor would encounter in free space, spinning at the rotor’s normal operating speed. That’s a mouthful of technical jargon, but a practical understanding of the nature of unbalance forces is important in applying balance tolerances to various machine rotors. It is also helpful in understanding the impact of fundamental changes in the recent replacement standard, 21940-11: 2016.

Aplicando las tolerancias de balanceo en rotores de diversas máquinas

  • August 2017
  • Number of views: 1336
Article

La especificación ISO para balancear rotores rígidos (ISO 1940-1) fue innovadora cuando fue introducida hace varias décadas. Esta norma estableció los Grados de Calidad de Balanceo basada en la velocidad teórica que el centro de masa de un rotor se encontraría en espacio libre, girando a la velocidad de funcionamiento normal del rotor. Esta es terminología técnica difícil de expresar, pero un entendimiento práctico de la naturaleza de las fuerzas de desbalanceo es importante para aplicar las tolerancias de balanceo en rotores de diversas máquinas. Esto también ayuda a entender el impacto de los cambios fundamentales en la reciente norma de reemplazo: 21940-11: 2016.

Understand motor/system baselines

  • May 2017
  • Number of views: 816
Trade press article — Maintenance Technology

Vibration readings provide the best early warning of developing problems in a motor or system component. Other parameters to monitor may include operating temperature of critical components, mechanical tolerances, and overall system performance, including outputs such as flow rate, tonnage, and volume.

Solve vertical pump motor vibration

Knowledge of common vibratory forces helps diagnose and correct problems

  • February 2017
  • Number of views: 1200
Trade press article — Processing Magazine

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.

EASA Technical Manual

  • August 2016
  • Number of views: 1137
FREE for Members of EASA
Book

EASA's most comprehensive technical document is available FREE to EASA members. Download the complete manual or just the sections you're interested in.

Vibration Analysis for Service Centers

  • June 2016
  • Number of views: 508
Booklet

This 48-page manual was developed following EASA’s 12-part Vibration for Service Centers webinar series. It serves as an introductory training resource for service center technicians and supervisors involved in measuring, evaluating, and correcting vibration and balancing issues on machines under repair – as opposed to the in-plant predictive maintenance tasks covered in most general classes on the subject.

Repairing Impeller Damage

  • May 2016
  • Number of views: 538
Webinar recording

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

Getting The Most From Your Electric Motors

  • February 2016
  • Number of views: 3179
Booklet

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.

Obteniendo Lo Máximo De Su Motor Eléctrico

  • February 2016
  • Number of views: 1579
Booklet

​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.

ANSI/EASA AR100: What's in the new 2015 edition?

  • November 2015
  • Number of views: 963
Article

EASA’s Recommended Practice for the Repair of Rotating Electrical Apparatus, designated as ANSI/EASA AR100, was first approved as an American National standard in 1998. Since then, it has been revised and approved four more times: 2001, 2006, 2010 and 2015. This article discribes the most recent changes.

Vibration for Service Centers (12-part webinar series)

  • October 2015
  • Number of views: 467
Webinar recording

This 12-part recording (15 hours) covers a wide range of topics on vibration.

This webinar series was designed to:

  • Provide EASA service center technicians with the technical knowledge they need to effectively measure and diagnose vibration on machines being tested in the service center.
  • Provide the foundation understanding necessary to use vibration data as an indicator of machinery condition
  • Provide the fundamental knowledge of dynamic balancing necessary to use common balancing instruments in the service center

Principles of Medium & Large AC Motors, 2nd Edition - NEMA

  • August 2015
  • Number of views: 862
Book

This manual, a companion to EASA's 2-day seminar of the same name, 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.

ANSI/EASA Standard AR100-2015: Recommended Practice for the Repair of Rotating Electrical Apparatus

  • August 2015
  • Number of views: 6067
Booklet

ANSI/EASA AR100 is a must-have guide to the repair of rotating electrical machines. Its purpose is to establish recommended practices in each step of the rotating electrical apparatus rewinding and rebuilding processes.

Most common methods of balancing overhung rotors

  • July 2015
  • Number of views: 964
Article

On occasion, service centers are asked to balance fan blades that are designed for an overhung mounting. The fan blade may be received mounted on the shaft, or without any shaft. The decision has to be made about how to mount the rotor in the balancing machine. One solution is to fabricate a mandrel to balance the fan blade between the machine pedestals. The other alternative is to mount the fan blade on the end of the shaft in an overhung configuration, with the fan blade outboard of both balancing machine pedestals. This would be the more expedient method if the fan blade is already mounted on the shaft in the overhung configuration.  How the fan blade is mounted doesn’t change the balance, as long as the fit to the shaft doesn’t change. So the question is, “Which is easiest?” Often it is easiest to mount the rotor in the overhung configuration, but balancing in that configuration presents some challenges. Those challenges are addressed here. 

Preventive and predictive maintenance of electric motors

  • January 2015
  • Number of views: 844
Article

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.

Tight vibration specification for electric motors: Effective or just expensive?

  • September 2014
  • Number of views: 409
Article

Vibration is the most effective and well-recognized parameter for assessing the mechanical condition of electric motors. Generally, lower vibration levels are equated with improved reliability. However, arbitrarily reducing the vibration level specification for acceptance of new and repaired motors will not necessarily result in improved reliability, and it will definitely increase costs. Further, reliance on vibration levels at 2x line frequency (2xlf) as an indicator of electric motor reliability is not effective.

A balancing act: Knowing and using the correct rotor specifications

  • November 2013
  • Number of views: 487
Article

A customer specifies that the rotor is to be balanced to 4W/N. Is that the 4W/N Military specification, or the 4W/N API specification?It could make a big difference. And, how do they compare to the ISO 1940/1 specification (G2.5, G1, etc.)? Fortunately, for symmetrical rotors, comparing the various standards is only a matter of a bit of easy algebra. For non-symmetrical rotors, the process gets a little more difficult because each of the specifications handles these cases differently. The other good news is that there are on-line references that provide graphic and tabulated comparisons.

Using Phase Angle to Diagnose Vibration Problems and Practical Analysis Tools from Basic Vibration Data

  • June 2013
  • Number of views: 31
Convention presentation

Vibration has three primary parameters; amplitude, frequency and phase. Previous presentations and papers have focused on the two most common parameters, amplitude and frequency. These two are the primary tools for determining if a machine vibration is a problem, and what the cause of the vibration might be. This paper, presented at the 2013 EASA Convention, focuses on the third parameter: phase angle.

Vibration of Belt Driven Machines

  • June 2013
  • Number of views: 496
Webinar recording

This presentation focuses on:

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

Converting vibration units not difficult if data is available

  • January 2013
  • Number of views: 407
Article

There are three fundamental parameters for machinery vibration data: amplitude, frequency and phase. When testing machine vibration, amplitude and frequency are the two primary measurements for acceptance testing and for diagnostics. Both of these parameters have several units in which they can be recorded. Converting from one unit of measurement to another is not difficult if both amplitude and frequency data are available. In many cases, only amplitude measurements are available, without the needed frequency information, so conversion to other amplitude units is not possible. Knowing when conversion is possible and how to a apply conversion formulas is important when assessing customer specifications and analyzing diagnostic data.

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

  • July 2012
  • Number of views: 241
Webinar recording

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

Is a failing bearing causing the vibration?

  • May 2012
  • Number of views: 467
Article

When machine vibration increases, one of the first questions asked is: "Is a failing bearing causing the vibration?" In the case of rolling element bearings, it is not difficult to separate vibration caused by a failing bearing from other common faults such as unbalance, misalignment, looseness, etc. But sorting out vibration from a failing rolling element bearing (here-after called "bearing vibration") from process sources such as flow induced and background vibration can be more demanding. The secret is to identify the frequency at which a flaw on a roller or raceway will impact the mating bearing component. These are commonly known as bearing fault frequencies.

Topics covered include:

  • Simple to complex steps in identifying bearing vibration
  • "Locate rpm" function
  • Occurance of sidebands

Resonance and its effect on mechanical structures

  • May 2011
  • Number of views: 1481
Article

Resonance is a property of all mechanical structures. It can be described as a sensitivity to a certain vibration frequency. For machinery such as electric motors, pumps, turbines, etc., it becomes a problem when small vibratory forces from the machine operation are amplified by mechanical resonance. The result can be very severe vibration levels, even when the exciting forces are small.

Vibration Problems with Vertical Motors on Pumps

  • December 2010
  • Number of views: 225
Webinar recording

When motors are installed on top of vertical pumps, high vibration is a common problem. 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.