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Articles in Industry Publications

Interpoles and Compensating Windings in DC Machines – What Do They Do?

  • December 2023
  • Number of views: 1460
Article

Unlike their AC counterparts, DC machines do not have rotating magnetic fields. Rather, there are fixed magnetic field axes for the field (direct axis) and armature (quadrature axis). Even though the armature is rotating, the magnetic field axis in the armature is fixed thanks to commutation, which allows the direction of current in an armature conductor to change as it passes from the region under one main field pole to the next.

Interpolos y Devanados de Compensación - ¿Qué es lo que hacen?

  • December 2023
  • Number of views: 1017
Article

A diferencia de sus homólogos de CA, las máquinas de CC no tienen campos magnéticos rotativos. Más bien, existen ejes de campo magnético fijos para el campo (eje directo) y la armadura (eje en cuadratura). Aunque la armadura esté girando, el eje del campo magnético de la armadura está fijo gracias a la conmutación, lo que permite que la dirección de la corriente en un conductor de la armadura cambie a medida que pasa debajo de un polo de campo principal al siguiente.

How to Measure Magnet Wire

  • March 2023
  • Number of views: 2406
Video

This video shows one step in collecting motor winding data: how to measure magnet wire.

Mitigating Risk with Insulation Systems

  • September 2021
  • Number of views: 11716
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: 10768
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.

DC Machine Data Sheet

  • December 2020
  • Number of views: 12492
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.

DC Motor Electrical Procedures

  • April 2020
  • Number of views: 10487
Webinar recording bundle

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DC Machine Inspection Report

  • August 2016
  • Number of views: 15804
Form/Worksheet

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

DC Machine As-Received Connection Form (2-, 4- and 6-Pole DC Machines)

  • August 2016
  • Number of views: 9970
Form/Worksheet

This inspection report helps record a DC motor's connection as it enters the service center. It is intended for use with 2-, 4- and 6-pole DC machines.

What’s new in the IEEE 43 insulation resistance testing standard?

  • April 2016
  • Number of views: 19897
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.

Keeping it cool: A look at causes of motor overheating

  • March 2015
  • Number of views: 13891
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.

Interpole strength: Determining correct number of circuits

  • February 2007
  • Number of views: 5795
Article

A conversation with two EASA members led to a method for determining whether the interpoles are connected with the correct number of circuits. Not only is this method easy, it's a refinement of the interpole polarity test we routinely perform on every repaired DC machine.

Interpole shims: Proper placement prevents arcing

  • November 2006
  • Number of views: 7280
Article

Have you ever wondered about the purpose of the shims found under the interpoles in most DC machines? Those shims are used by the manufacturer to adjust the interpole strength. If they are lost, left out or mixed up, the result will be a DC motor or generator that arcs - especially when loaded.

Training Film 21: Testing DC Machines

  • June 1987
  • Number of views: 12415
Video

Training Film 19: Layer-Winding DC Field Coils

  • June 1985
  • Number of views: 7329
Video

Covers all necessary steps for layer-winding DC field coils, how to layer-wind a shunt field coil, how to reinsulate an interpole field coil, and how to install large field coils in the frame.

Training Film 18: Random-Winding DC Field Coils

  • June 1984
  • Number of views: 7124
Video

Illustrates procedures for manufacturing random-wound interpole and main field coils for DC machines. Covers everything from removing old coils and taking data to installing and connecting new coils, including how to construct winding forms and jigs, how to shape coils to conform with the curvature of the field frame and how to insulate field coils. Both “wet” and “dry” winding techniques are illustrated.