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Applying balance tolerances to various machine rotors

  • August 2017
  • Number of views: 155
  • Article rating: No rating
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: 195
  • Article rating: No rating
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.

Power supply considerations when building a large growler

  • July 2017
  • Number of views: 116
  • Article rating: No rating
Article

When considering building a large growler for testing armatures and rotors, the initial decision typically is to select a kVA rating. A primary reason for this is that the growler will need to be connected to a power supply of sufficient ampacity at the supply voltage. To help simplify a complex design process, four kVA ratings have been selected for this article.

Consideraciones sobre la fuente de alimentación al construir un gran growler

  • July 2017
  • Number of views: 77
  • Article rating: No rating
Article

Cuando se considera la construcción de un gran growler para probar rotores y armaduras, la decisión inicial típica es seleccionar la potencia en kVA. La razón principal para esto es que el growler necesitará ser conectado a una fuente de alimentación que tenga suficiente amperaje. Para ayudar a simplificar el complejo proceso de diseño, en este artículo hemos seleccionado cinco potencias expresadas en kVA.

DC machine inspection report

  • August 2016
  • Number of views: 240
  • Article rating: 5.0
Form/Worksheet

A convenient incoming inspection report for basic DC motor conditions and test values.

DC machine data sheet

  • May 2016
  • Number of views: 101
  • Article rating: No rating
Form/Worksheet

EASA's DC Machine Data Sheet provides all the fields necessary on a simple one-page form to accurately record all the details about the machine being repaired.

Armature winding designs demystified with helpful tips

  • July 2014
  • Number of views: 85
  • Article rating: No rating
Article

While there are many similarities between 3-phase AC stators and DC armatures, there are some unique aspects to DC armature design; these can be extremely helpful to those who understand some little-known tips. The goal of this article is to share those tips.

Flashover: Causes and cures for damage to brushholders, commutators

  • April 2013
  • Number of views: 299
  • Article rating: No rating
Article

There are times when a DC motor or generator experiences a catastrophic failure and the customer wants to know why it happened. One type of failure that seems to stimulate lively conversation is when the failure involves dramatic damage to the brushholders and commutator. The term "flashover" describes the appearance of the failure; the very name conveys an accurate mental image of the failure. The questions that arise next are predictable: "What caused this?" and "What can be done to prevent a recurrence?" Or, if the motor was recently repaired: "What did you do to my motor to cause this?!" The purpose of this article is to help you answer those questions.

How to strip an armature without degrading the core

A simple and efficient method to improve quality and save labor

  • January 2008
  • Number of views: 110
  • Article rating: No rating
Article

We all know that stator cores should be burned at a controlled temperature to prevent lamination deterioration that can lead to harmful eddycurrent losses. But what about armatures?

Surge testing of DC motor and generator armatures

  • July 2007
  • Number of views: 200
  • Article rating: 5.0
Article

In the April 2007 issue of CURRENTS, we covered surge testing anomalies, specifically for AC windings. The surge test can be used for DC windings as well. It can be a useful tool for evaluating armatures and some DC fields. A note of caution: If a winding does not have a minimum insulation resistance per ANSI/EASA AR100-2006, it is not safe to apply an overpotential test (surge or high potential). Surge testing shunt fields may not provide meaningful results if the surge pulse decays too quickly - if it dissipates through only the first few hundred turns. To obtain a test voltage high enough to test every turn would require too high a voltage. That high voltage would overstress the groundwall insulation.

Getting The Most From Your Electric Motors

Getting The Most From Your Electric Motors - coverThis 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.

This booklet covers topics such as:

  • Installation, startup and baseline information
  • Operational monitoring and maintenance
  • Motor and baseline installation data
  • How to read a motor nameplate
  • Motor storage recommendations

LEARN MORE AND DOWNLOAD MÁS INFORMACIÓN Y DESCARGAR

READ MORE ABOUT THE FEATURES AND BENEFITS

EASA Technical Manual

EASA Technical Manual cover

The EASA Technical Manual is the association's definitive and most complete publication. It's available FREE to members in an online format. Members can also download PDFs of the entire manual or individual sections.

VIEW & DOWNLOAD

ANSI/EASA AR100-2015

ANSI/EASA AR100-2015 cover

Recommended Practice for the Repair of Rotating Electrical Apparatus
This 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.

DOWNLOAD - ENGLISH

DESCARGAR - ESPAÑOL

EASA AR200

EASA AR200: Guide for the Repair of Power and Distribution Transformers cover

Guide for the Repair of Power and Distribution Transformers
This document establishes guidelines for each step of the repair of power transformers, describing record keeping, tests, analysis, and general guidelines for the repair of power transformers.

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