The MX322^TM analogue, 3-phase sense Automatic Voltage Regulator (AVR) and forms part of the excitation system for a brush-less alternator. Excitation power is derived from a 3-phase permanent magnet generator (PMG), to isolate the MX322™ AVR control circuits from the effects of non-linear loads and to reduce radio frequency interference on the alternator terminals.

Sustained alternator short circuit current is an additional feature of the PMG system.