Occasionally a synchronous motor is configured without an external shaft to drive a load. In this case, the sole purpose of the synchronous motor is improving overall power factor of an electrical distribution system. What is the name of the synchronous motor so constructed?

Correct Answer: Option D — Synchronous condenser

A synchronous condenser is an un-loaded synchronous motor connected to a distribution system solely to adjust power factor. By varying its DC field excitation, it can generate or absorb reactive power (leading or lagging), correcting low power factors common with heavy inductive loads like marine induction motors and pumps.