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.

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.

Vertical motors differ from horizontal motors in numerous ways, yet some view them as “just a horizontal motor turned on end.” The obvious differences are the (usually) thrust bearings, with arrangements varying from single- to three-thrust bearings with different orientations suited for specific load, rpm and applications. Less obvious differences are in the ventilation arrangements, shaft stiffness, degrees of protection and runout tolerances. This recording will cover those topics.

There are times when an application calls for a motor to carry a radial load for which sleeve bearings are not suitable. In cases such as low rpm, unusual frames, etc., it may be desirable to convert a customer's existing sleeve bearing motor rather than obtaining a ball/roller replacement motor. This article contains suggested procedures as well as cautions about potential problems with such conversions.

This webinar recording focuses on:

• Motor assembly issues
• Electrical and mechanical inspection
• Static and run testing
• AC motors with ball, roller and sleeve bearings

My first exposure to synthetic lubricants for rolling element bearings was during repair of high-speed, automotive engine-test dynamometers. For several years, our service center had repaired similar machines with rolling element bearings, but they were all oil lubricated by pump systems with specially-selected fittings near the bearings to deliver only small amounts of oil per minute.

We began to see rolling-element-bearing machines in for repair that were grease lubricated, and these displayed a specific make and type of lubricant on the nameplate. We purchased what was specified on the nameplate and all was well. Over time, we began to see more machines specifying the same make of grease, but a different grade or type. This led me to begin looking into the differences in the products.

Existen ocasiones en las que una aplicación requiere que un motor soporte una carga radial para la que los cojinetes de deslizamiento no son adecuados. En casos como bajas revoluciones, carcasas inusuales, etc., puede ser conveniente convertir el motor del cliente montado sobre cojinetes de deslizamiento envés de obtener un motor de repuesto con rodamientos de bolas / rodillos. Este artículo contiene procedimientos sugeridos y advertencias sobre problemas potenciales relacionados con dichas conversiones.

Mi primera experiencia con lubricantes sintéticos para rodamientos con elementos rodantes fue durante la reparación de dinamómetros para probar motores de automóviles de alta velocidad. Durante varios años nuestro centro de servicio había reparado máquinas similares con rodamientos con elementos rodantes, pero todas ellas estaban lubricadas con sistemas de bombeo de aceite con accesorios especiales cerca de los rodamientos para suministrar solo pequeñas cantidades de aceite por minuto.

Comenzamos a ver máquinas enviadas para reparación con rodamientos con elementos rodantes lubricadas con grasa y estas indicaban en la placa de datos una marca y tipo de lubricante específicos. Compramos lo que estaba especificado en la placa y todo salió bien. Con el tiempo, comenzamos a ver más máquinas que especificaban la misma marca de grasa, pero con un tipo o grado diferente y esto me condujo a comenzar a buscar las diferencias en los productos, ya que uno era muy costoso y tenía una vida útil limitada.

End users frequently demand that EASA service centers provide an array of test data at the conclusion of the service/repair process. These tests are normally to validate compliance with the customer’s motor repair specifications. One of the more common tests involves running the motor no-load and providing the motor owner with electrical test information and vibration spectrums covering various frequency bands.

Many of your customers have good in-house predictive maintenance departments and others outsource that skill. Either way, they should know when a bearing is deteriorating and remove the motor from service before it turns into a catastrophic failure. That saves a lot of maintenance dollars, which is great. But if the customer stops there, without discovering why that bearing is bad, your repaired motor could be returned with the same problem again. Defective bearings often hold a great deal of evidence, if we only look for it. The key is communication with the customer so that we repairers know that the motor was removed for bearing faults, and so that we can go a step further in the diagnostic process. Especially with the prevalence of variable frequency drives (VFDs), bearing currents cause a significant number of bearing failures. If you know the motor is operating from a drive, there are corrective measures to prevent future failures of the same type. And those extra steps are billable extras. Neglecting these additional inspection steps is like leaving money on the table, for both the service center and the customer.