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.

This article addresses electrical testing and inspection of installed 3-phase squirrel cage motors. The main purposes of testing installed electric motors are condition assessment for continued service or to diagnose suspected faults. The emphasis here will be on diagnostic electrical testing and interpretation, as well as physical inspection key points. Note: Most of the tests and inspections described in this article can also be performed on 3-phase wound rotor motors, and induction and synchronous generators.

Este artículo cubre las pruebas eléctricas y la inspección de motores trifásicos jaula de ardilla que han sido instalados. Los principales objetivos al probar los motores en el sitio de trabajo son: Evaluar su condición para garantizar su funcionamiento continuo odiagnosticar presuntos fallos. Aquíharemos énfasis en las pruebas y enla interpretación de los resultados, asícomo también, en la inspección física de los puntos clave. Nota: La mayoría de las prue­bas descritas también se pueden realizar a los motores con rotor bobinado y en los gen­eradores sincrónicos y de inducción. 

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.

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.

This article demonstrates the suitability of resin rich insulation systems for hydro generator service and highlights the advantages of being able to introduce remedial measures during the life of the winding to address issues and ensure that acceptable winding life is achieved 

This version of the EASA Motor Rewind Database software takes a large leap forward with the data that it provides members. Most notably, it now has the ability to connect to a live, ever-expanding online database of more than 250,000 windings. This live database will be continuously monitored, updated and corrected as needed by EASA’s Technical Support Staff.

This article looks at an issue encountered with new air-cooled machines rated at 13.8 kV that generated large quantities of ozone and had very high partial discharge levels. The basic problem with the windings in these machines was incorrect spacing of the end turns and the main leads. There was also a lack of space between the series and group connections in the windings. 

Recientemente trabajé en una máquina nueva de 13.8 kV de tensión nominal, enfriada por aire,   que pro-ducía grandes cantidades de ozono y tenía grandes niveles de descargas parciales. El problema básico con  los bobinados de esta máquina era  el espacio incorrecto entre las cabezas de bobina y los cables  de salida prin-cipales. También había poco espacio entre las series y las conexiones entre los  grupos del bobinado.