AVR AS540 Automatic Voltage Regulator Stamford (A059F437)

The AVR provides closed loop control by sensing the alternator output voltage at the main stator windings and adjusting the exciter stator field strength.

Voltage induced in the exciter rotor, rectified by the rotating diodes, magnetizes the rotating main field which induces voltage in the main stator windings.

A self-excited AVR receives power from the alternator output terminals or a special auxiliary winding in the main stator winding.

The STAMFORD Diode Failure Detector (DFD) senses ripple current in the exciter output caused by diode failure in short or open circuit, and switches an internal relay if it persists for 7 seconds.