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Synchronous Machine

SM. An AC electrical machine operated with a constant electromagnetic field.

Definition in an IEEE Standard

Source: 1 (p15)

A synchronous machine is an ac electrical machine operated with a constant electromagnetic field. Its instantaneous speed of normal operation is exactly proportional to the frequency of its ac voltage. An SM with a round rotor has a uniform air gap, so that the reluctance does not depend on the flux position. Contrarily, the air gap of an SM with a salient-pole rotor varies circumferentially around the rotor, resulting in a non-uniform reluctance.


Last modified: 2025-06-20

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  1. (2025). IEEE Recommended Practice for Use and Functions of Virtual Synchronous Machines. https://doi.org/10.1109/IEEESTD.2025.10850696