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Articles in Industry Publications

Static Couple Balancing

  • March 2022
  • Number of views: 5105
FREE for Members of EASA
Webinar recording

Learn the basics of static couple balancing and how and when to use it.

Fundamentos de Reparación Mecánica de Motores Eléctricos

  • March 2022
  • Number of views: 14633
Book

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.

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.

Mechanical Reference Handbook

  • June 2021
  • Number of views: 4867
Handbook

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.

Dynamic Balancing on Pump Impellers

  • February 2021
  • Number of views: 12847
Article

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.

Balanceo Dinámico de los Impulsores de las Bombas

  • February 2021
  • Number of views: 11341
Article

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.

ANSI/EASA Standard AR100-2020: Recommended Practice for the Repair of Rotating Electrical Apparatus

  • September 2020
  • Number of views: 54522
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.

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

  • February 2020
  • Number of views: 53256
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.

Root Cause Failure Analysis, 2nd Edition

  • September 2019
  • Number of views: 30714
Book

This book was developed to help electric motor technicians and engineers prevent repeated failures because the root cause of failure was never determined. 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.

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

  • February 2019
  • Number of views: 15377
Book

Las versiones impresas 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: 9027
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: 7265
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: 8455
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: 10595
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.

Solve vertical pump motor vibration

Knowledge of common vibratory forces helps diagnose and correct problems

  • February 2017
  • Number of views: 13851
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.

Repairing Impeller Damage

  • May 2016
  • Number of views: 4302
Webinar recording

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

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Vibration for Service Centers (12-part webinar series)

  • October 2015
  • Number of views: 5737
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
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Principles of Medium & Large AC Motors, 2nd Edition - NEMA

  • August 2015
  • Number of views: 13779
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.

Most common methods of balancing overhung rotors

  • July 2015
  • Number of views: 9756
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. 

A balancing act: Knowing and using the correct rotor specifications

  • November 2013
  • Number of views: 4332
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.

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

  • July 2012
  • Number of views: 3693
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
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How to Balance Overhung Fans

  • October 2011
  • Number of views: 9619
Webinar recording

This presentation shows a methodical approach and techniques for tackling this difficult balancing problem.

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Balancing Tips: In-house and On-site

  • June 2011
  • Number of views: 4042
Convention presentation

An understanding of basic vectors and balancing vector pictures is essential for optimizing dynamic balancing in the service center and in field balancing. This paper provides the foundation for balancing tasks either in-house or on-site.

Mechanical Repair Fundamentals of Electric Motors (2nd Edition)

  • January 2010
  • Number of views: 10411
Book

Fundamental to every good mechanical repair is the ability to disassemble, repair and reassemble the motor correctly without unnecessary damage to any of the motor parts. This sounds simple, and yet too many costly mistakes are made in this process of taking things apart. If every motor repaired was in “as new” condition, the task would be much simpler. This manual introduces much of the basics to electric motor disassembly and assembly.

Dynamic balancing of rotors and armatures

  • September 2006
  • Number of views: 6842
Article

This article describes machine balancing of the rotating components of motors and generators, primarily rotors and armatures. The methods described here, in general, can be applied to on-site balancing if the rotating component is accessible. The intent is to describe the methods of attaching balance weights, not determining acceptable balance level or the location and amount of correction weight.

Improving the Repair Process for Optimum Productivity

  • June 2005
  • Number of views: 2949
Convention presentation

We all know that seemingly small time savings can significantly improve the bottom line. For a service center with a 12% return on investment (ROI), shaving a few minutes off each job is the equivalent of adding 2 manmonths of billing per productive employee. This paper, from the 2005 EASA Convention, provides many tips for increaseing productivity.

Fan balancing tips: Understanding basics will improve your skills

  • November 2004
  • Number of views: 6775
Article

Most service centers balance rotors routinely, with few surprises in the process. Most of us do not balance fans nearly as often as rotors. The fan balancing tips in this article should be helpful.