Few things are less exciting in the motor world than a large synchronous motor that refuses to start—and all too often, the root cause is excitation. This article provides an overview of what synchronous motor excitation is, how it works, and the common issues you are likely to encounter.

Pocas cosas resultan menos estimulantes en el mundo de los motores que un gran motor sincrónico que se niega a arrancar; y, con demasiada frecuencia, la causa raíz reside en la excitación. Este artículo ofrece un panorama general de qué es la excitación de un motor síncrono, cómo funciona y los problemas habituales que es probable que encuentre. 

Advancement in power electronics over the last few decades has made it possible to utilize a variety of rotating electric machines that would otherwise not be feasible. One such class of machines is called reluctance machines because of the way they produce an electromagnetic torque. A reluctance machine is an electric machine in which torque is produced by the tendency of its movable part to move to a position where the inductance of the excited winding is maximized.

Los avances en la electrónica de potencia en las últimas décadas han permitido el uso de una variedad de máquinas eléctricas rotativas que de otro modo no sería factible. Una de ellas se denomina máquina de reluctancia debido a la forma en la que dichas máquinas producen un torque electromagnético. Una máquina de reluctancia es una máquina eléctrica en la cual el torque se produce por la tendencia de su parte móvil a moverse a una posición donde se maximiza la inductancia del devanado excitado.

This recording explores features of synchronous and switched reluctance machines.

Service centers are seeing an increase in the number of SRMs received for repair, and some of the technicians encountering them are unfamiliar with how they work. As with any other rotating machine, a basic understanding of operating principles can be useful in troubleshooting and repair. One of the most critical things for service center personnel to understand upfront is that these machines cannot be operated without a special drive, which typically would need to be supplied by the end-user or the manufacturer.

Los centros de servicio están notando un incremento en el número de SRMs que reciben para reparar y algunos de los técnicos no están familiarizados con su funcionamiento. Como cualquier otra máquina rotativa, un conocimiento básico de los principios de funcionamiento puede ayudar a detectar problemas y durante la reparación. Uno de los puntos más críticos para el personal del centro de servicios es entender de antemano que estas máquinas no pueden ser operadas sin un drive especial, el cual normalmente necesita ser suministrado por el usuario final o el fabricante.

Is the induction motor the preferred answer in industrial drive applications? What is happening to the synchronous, DC and wound rotor motor (WRM) in those applications?

The paper "Synchronous Machine Repair Tips" by Chuck Yung, presented at the EASA Convention 2010, provides comprehensive guidance on the repair and maintenance of synchronous machines, which are a subset of AC motors. While the stator of a synchronous machine is similar to that of a squirrel cage induction motor (SCIM), the rotor is substantially different. Synchronous machines offer several advantages, including the ability to operate exactly at synchronous speed, control power factor, improve plant-wide power factor, lower operating costs, and reduce current, which can result in savings in switchgear and power cable routing.

Proper testing of a synchronous motor is crucial for validating repair, reconditioning or remanufacture. There are several types of synchronous motors and a brief description of each will be given prior to discussing testing.