The circuitry of the R448 Automatic Voltage Regulator (AVR) provides closed loop control of the alternator output voltage by regulating the exciter field current.
The primary winding has a voltage in ratio to that of the alternator (characteristic shunt), the next has a voltage in proportion to the stator current (compound characteristic: booster effect).
The power supply voltage is rectified and filtered before being used by the AVR monitoring transistor. With PMG excitatioin, a permanent magnet generator (PMG) added to the alternator supplies the AVR with voltage which is free of the main alternator winding.
This is built-in at the rear of the machine and connected to the R448 AVR, and the ST9 jumper must be disconnected.
Input voltage: 70-140V AC, (PMG, or auxiliary winding, single, three phases)
model number: R448
Part Number: R448
Details: *Quadrature droop adjustment
*AVR Voltage adjustment
*Stability adjustment
*LAM Threshold (underspeed) adjustment
*Excitation ceiling adjustment
*Selection of single phase or three phase*
*voltage sensing
*Selection of normal or rapid response time
*50 Hz or 60 Hz frequency option
*Remote voltage adjustment option
*LAM enable/disable option
*Alternator frame selection
*Excitation system selection
Specificaion
Input voltage: 70-140V AC, (PMG, or auxiliary winding, single, three phases)
Reaction is measured : 90-480V AC
MAX. output :DC 10A 125V
Function: Built-in low-speed , over excitation LAM,
REGULATION: +/-0.5%
Voltage regulation ± 0.5%
Remote voltage adjustment range ± 5%
Short circuit capability 3 x Irated for 10 seconds
Voltage sensing 95 to 140 volts (50/60 Hz)
170 to 260 volts (50/60 Hz)
340 to 520 volts (50/60 Hz)
Response time Normal (1 sec) for ± 20% voltage variation
Rapid (0.3 sec) for ± 20% voltage variation
