... Automatic Voltage Regulator: Leroy Somer AVR; R230, R250, R438, R448, R449 Technical Data:The R250 is an analogic Automatic Voltage Regulator with ... .2, 47.2. Compatible with the SHUNT excitation system. The R250 is in Compliance with: IEC, VDE, NEMA, BS, CSA, UL508 ... supply the following Automatic Voltage Regulator: Leroy Somer AVR; R230, R250, R438, R448, R449 AVR ...