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Articles in Industry Publications

Inverter Duty Three-Phase Motor Windings

  • June 2024
  • Number of views: 1899
Article

With the advent of solid-state electronic variable frequency drives (VFDs) in the late 1980s, it was found that the windings of motors used on VFDs failed more frequently than when powered by a utility (sine wave) supply. By the turn of the century, motor manufacturers had gained a better understanding of how VFDs affected motor windings. This article describes the materials and methods associated with inverter duty windings.

Devanados para motores trifásicos Inverter Duty

  • June 2024
  • Number of views: 1052
Article

Con la llegada de los variadores de frecuencia electrónicos (VFD) de estado sólido a fines de la década de 1980, se descubrió que los bobinados de los motores que funcionaban con VFDs fallaban con más frecuencia que al estar alimentados con la energía convencional (onda sinusoidal). A principios de siglo, los fabricantes de motores habían comprendido mejor cómo los VFD afectaban los devanados del motor, y al igual que los proveedores de materiales electro, aislantes habían desarrollado materiales y métodos para mejorar la confiabilidad de los devanados de los motores alimentados con VFDs. En este artículo, describiremos los materiales y métodos asociados con los devanados inverter duty.

Choosing the Right Insulation System for Medium Voltage Rewinds

  • April 2024
  • Number of views: 3040
Article

The insulation system chosen for any rewind should be suitable for the application, the voltage class, and the winding process capability of the service center. In most cases, adherence to “equal to or better than” selection is a good practice.

Escogiendo el sistema de aislamiento adecuado para rebobinados de media tensión

  • April 2024
  • Number of views: 2614
Article

El sistema de aislamiento escogido para cualquier rebobinado debe ser el adecuado para la aplicación, el voltaje y la capacidad del proceso de rebobinado del centro de servicio. En la mayoría de los casos, seleccionar una opción "igual o mejor" es una buena práctica.

Performing an Insulation Resistance Test

  • March 2023
  • Number of views: 7493
Video

This video explains how to check the ground insulation of an AC motor winding using the insulation resistance (IR) test.

Why “White Coils” are a “Red Flag”

The importance of preventing the ingress of air during global vacuum pressure impregnation of form-coil windings

  • September 2022
  • Number of views: 3102
Article

The goal of vacuum pressure impregnation is complete saturation of a winding with insulating resin. As resin penetrates the insulating materials, it causes them to darken. If some insulation is a lighter shade, the coil or jumper is not fully saturated. The winding is not properly protected, and if the problem is not addressed, it is likely to cause premature failure of the unit. This could result in costly warranty work, or at a minimum, will be a failure to provide your customers with the quality they expect and deserve.

Porqué las "Bobinas Bancas" son una "Señal de Alarma"

La importancia de prevenir el ingreso de aire durante la impregnación global por vacío y presión de los bobinados preformados

  • September 2022
  • Number of views: 2276
Article

El objetivo de la impregnación por vacío y presión (VPI) es saturar completamente un devanado con resina aislante. A medida que la resina penetra en los materiales aislantes, los oscurece y al drenar la resina VPI del devanado, todo el aislamiento de las cabezas queda oscuro en un tono uniforme. El aislamiento de la conexión también debe quedar oscuro de forma pareja. Si algún aislamiento muestra un tono más claro, la bobina o el puente no han quedado completamente saturados y el devanado no está debidamente protegido. Si no se soluciona el problema, es probable que esto provoque un fallo prematuro en el equipo. Esto podría generar una garantía costosa o, como mínimo, la reparación no brindará a sus clientes la calidad que esperan y merecen.

Resin Treatment Tips for Service Centers

  • October 2021
  • Number of views: 10230
Article

One of the most briskly debated issues in our industry is the comparison – and procedures for – vacuum pressure impregnation (VPI) versus dip & bake. For this article, the discussion has been expanded to include trickle epoxy and B-stage coils.

Consejos para el Tratamiento con Resina en los Centros de Servicio

  • October 2021
  • Number of views: 9021
Article
Uno de los temas más debatidos en nuestra industria es la comparación y los procedimientos de impregnación a presión al vacío (VPI) versus inmersión y horneado. Para este artículo, la discusión se ha ampliado para incluir bobinas de etapa B y epoxi de goteo.

Mitigating Risk with Insulation Systems

  • September 2021
  • Number of views: 12381
Article

Relevant standards including IEC 60085 and IEEE 1 have similar definitions for electrical insulating materials (EIM) and electrical insulation systems (EIS). As with any system, there is an interaction between the materials used, and the insulation system developers take great care to ensure that this interaction does not lead to undesirable outcomes.

Mitigando El Riesgo En Los Sistemas De Aislamiento

  • September 2021
  • Number of views: 11428
Article

Diferentes normas relevantes incluyendo la IEC 60085 y la IEEE 1 definen de forma similar los materiales electro aislantes (EIM) y los sistemas de aislamiento eléctrico (EIS). Como en cualquier sistema, existe una interacción entre los materiales usados y los diseñadores de los sistemas de aislamiento cuidan todos los detalles para evitar que esta interacción produzca resultados indeseados.

Inverter Duty Motor Rewinding

  • April 2021
  • Number of views: 13835
FREE for Members of EASA
Webinar recording

This webinar recording reviews the failures associated with 3-phase motors on Variable Frequency Drives (VFDs) and how to rewind to limit future failures.

Best AC Rewind Practices

  • February 2021
  • Number of views: 15886
FREE for Members of EASA
Webinar recording

This webinar recording shares some of the “best practice” rewind methods used by (and learned from) EASA service centers around the world: connection recognition, best insulating materials, wire choices and tips to save time and effort.

AC Motor Electrical Procedures

  • April 2020
  • Number of views: 10223
Webinar recording bundle

A special discounted collection of 11 webinar recordings focusing on AC motor electrical procedures.

Just $55 for EASA members!

BUY A COPY

Working with AC Windings

  • April 2020
  • Number of views: 12358
Webinar recording bundle

A special discounted collection of 12 webinar recordings focusing on AC motor windings.

Just $60 for EASA members!

BUY A COPY

High-Potential Testing of AC Windings

  • December 2019
  • Number of views: 8867
Webinar recording

High-potential testing is routinely used to assess the ground insulation of AC stator windings in-process, after completion of a rewind and post-delivery. This webinar covers types of high-potential tests, testing standards, evaluating test results, and more.

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Considerations for surface masking and winding treatment processes

  • March 2018
  • Number of views: 10772
Article

One of the least popular tasks to perform related to winding treatment processes is preparation and cleanup of fits, threaded holes and machined surfaces. Many service centers invest additional time in the preparation stage so as to minimize the cleanup stage. The most common approach to protecting these surfaces during winding treatment is to utilize masking compounds or dry release sprays.

In the last year, EASA’s technical support staff has received a number of inquiries from members seeking replacement recommendations for Famous Lubricants' “Special Masking Compound” which is currently unavailable. It is believed at this time that the manufacturer intends on continuing production at some point in the future though the time frame is not known. This specific problem leads to a more general question: What is a good practice for choosing a product to mask these surfaces?

Consideraciones para enmascarar superficies y procesos de tratamiento de bobinados

  • March 2018
  • Number of views: 9718
Article

Una de las actividades a realizar menos populares relacionadas con el tratamiento de los bobinados, es la preparación y la limpieza de los ajustes, agujeros roscados y superficies mecanizadas. Muchos centros de servicio invierten tiempo adicional durante la etapa de preparación para minimizar la etapa de limpieza. El enfoque más común para proteger estas superficies durante el tratamiento del bobinado consiste en utilizar compuestos para enmascarar o aerosoles de liberación de película seca. Durante el último año, el departamento de soporte técnico de EASA ha recibido una serie de consultas por parte de los miembros buscando recomendaciones para reemplazar el producto “Special Masking Compound” de Famous Lubricants’ (ver Figura 1) que actualmente no se encuentra disponible. Se cree en estos momentos que el fabricante tiene la intención de continuar con la producción en el futuro, aunque el plazo se desconoce. Este problema específico conlleva a una pregunta más general: ¿Cuál es una buena práctica para escoger un producto para enmascarar estas superficies?

Induction Motor Rotor Windings: Squirrel-Cage and Wound Rotor Basics for the Technician

  • January 2018
  • Number of views: 11708
Webinar recording

This presentation covers induction motor basics for squirrel-cage and wound rotor motors

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Getting the most from power factor tip-up testing

  • April 2017
  • Number of views: 17631
Article

The power factor tip-up test is commonly used as a quality measurement for new coils and windings manufactured for AC motors and generators rated 6 kV and higher. It can also be useful in the rewind shop to verify the quality of a newly-installed coil system including the effectiveness of VPI processing.

Aprovechando al máximo la prueba de factor de potencia tip-up

  • April 2017
  • Number of views: 16452
Article

 

La prueba de volcado del factor de potencia se usa comúnmente como una medida de calidad para bobinas y devanados nuevos fabricados para motores de CA y generadores con clasificación de 6 kV y más. También puede ser útil en el taller de rebobinado para verificar la calidad de un sistema de bobina recién instalado, incluida la efectividad del procesamiento de VPI.

How To Wind Three-Phase Stators (Version 2)

Self-paced, interactive training for stators 600 volts or less

  • February 2017
  • Number of views: 15849
Software

This EASA software is a valuable interactive training tool ideal for training your novice(s) ... and even experienced winders will learn from it. The CD teaches how to wind in a richly detailed, step-by-step approach which includes narrative, animations and video clips, with tests to assess student comprehension. 

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The Basics: Taking Motor Data

  • September 2016
  • Number of views: 4759
Webinar recording

This webinar covers:

  • Photo documentation
  • Paper documentation
  • Measurements
  • Winding data: turns, wire size, connection, core dimensions
  • Keeping cause of failure questions in mind 
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The Basics: AC Motor Design

  • July 2016
  • Number of views: 8560
Webinar recording

This webinar recording covers: 

  • Various types of AC motors and bases for operation
  • Squirrel cage induction motor rotor design / construction
  • Squirrel cage induction motor stator design / construction
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Rewinding Tips for Premium-Efficient Motors

  • June 2016
  • Number of views: 6697
Webinar recording

This webinar recording covers: 

  • Importance of core loss testing
  • Methods to reduce core losses
  • Slot fill improvement without reducing copper
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What’s new in the IEEE 43 insulation resistance testing standard?

  • April 2016
  • Number of views: 22740
Article

The Institute of Electrical and Electronics Engineers (IEEE) standard for insulation resistance testing of motor and generator windings that was published in 2002 has been revised. The 2013 edition was published in March 2014. This article examines the changes to the standard.

¿Qué hay de nuevo en la norma para pruebas de resistencia de aislamiento IEEE 43?

  • April 2016
  • Number of views: 35487
Article

La norma para realizar las pruebas de resistencia de aislamiento en los devanados de motores y generadores del Instituto de Ingenieros Eléctricos y Electrónicos (IEEE), publicada en el 2002 ha sido revisada. La edición del 2013 fue publicada en Marzo del 2014. Este artículo examina los cambios al estándar.

Insulation Material Properties & Testing: How the Insulation System Works

  • April 2016
  • Number of views: 4380
Webinar recording

This webinar recording covers:

  • Insulation system versus insulation materials
  • Stresses imposed on insulation systems
  • Insulation system components / functions
  • Typical testing of system components / functions
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Stator Rewinds: When Things Get Tight

  • June 2015
  • Number of views: 4474
Webinar recording

When preparing to rewind random or form wound stators, sometimes there just doesn’t seem to be enough room in the stator slot for the desired conductor area and insulation quantities. Common scenarios encountered are redesigns from concentric to lap, changes to higher voltages or aggressive designs from the OEM.

This webinar will look at balancing stator copper losses against insulation reliability.

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Keeping it cool: A look at causes of motor overheating

  • March 2015
  • Number of views: 15124
Article

We know that excessive temperature and moisture are the largest contributors to bearing and winding failures. Understanding the source of the increased temperature will help us to correct the problem and improve the machine’s life expectancy.