R449 voltage regulator of a sealed electronic devices, by adjusting the excitation current in order to stabilize the output voltage of the brushless generator.

Specifications
Normal AVR supply power: 2 auxiliary windings
Shunt supply: 150V - 50/60Hz
Rated overload current: 15A, 10s
Electrionic built-in(overload, shour circuit, and loss of sensing) prodtection: If Excitation current raises over 10 Amps for more than 10 seconds, excitation current will drops automatically to about 1A.
To reset AVR protection, generator must be stopped(or by cutting supply voltage to the AVR).

Protection of power inputs by fuses F1
Voltage sensing: 5VA insulated transformer with input voltage taps at:
Terminals 0-110V=95-140V
Terminals 0-220V=170-260v
Terminals 0-380V=340-520V
Load current 7A
Overload current 15A, 10s