For those who work almost exclusively with lap or concentric wound three-phase stators, wave wound rotor connections can be a challenge. This is especially true if connection data gets lost or if an existing winding connection is damaged during a failure. In these cases, it is useful to have a practical method for laying out a valid connection diagram. 

Para aquellos que trabajan casi exclusivamente con estatores trifásicos con devanados imbricados o concéntricos, las conexiones de los rotores bobinados con devanados ondulados pueden ser un reto. Esto es especialmente cierto, cuando los datos de conexión se pierden o cuando el fallo en el bobinado provoca daños en la conexión existente. 

Wound rotor (WR) motors represent only a small fraction of all electric motors in service. In reviewing the EASA Technical Support call logs, one would conclude that there are many more wound rotor motors in service. Because many of us do not work on wound rotor motors often, it is understandable that not everyone has a clear understanding of how they differ from a squirrel cage motor. The purpose of this article is to dispel some misconceptions about how they work and to offer valuable tips for failure analysis, repair and testing. Other topics covered include: Secondary voltage Crane applications Testing tips, after assembly

The poles for the stator and rotor of the wound-rotor motor must be equal. When rewinding any wound-rotor motor, watch for consequent-pole connections. Grouping alone is not a reliable indicator of poles. The best way to understand the process is to visualize the rotating electrical field in the stator of a wound-rotor motor. The field rotates one direction, so that when the rotor is driven in the opposite direction the passing frequency is increased. If the speeds are the same (i.e., the same number of poles as the drive motor) the output frequency will double.