Leroy Somer AVR R221 – Automatic Voltage Regulator

The Leroy Somer R221 is a dependable Automatic Voltage Regulator (AVR) designed for small to medium alternators using SHUNT or AREP excitation systems. It delivers precise voltage control, excellent transient response, and long-term operational stability, ensuring reliable generator performance under changing load and environmental conditions. Compact and durable, the R221 is ideal for both industrial and commercial generator applications requiring consistent voltage regulation.

Key Specifications:

• Voltage Regulation: ±1% steady-state accuracy

• Excitation Current: 4 A continuous, 7 A maximum for 10 seconds

• Sensing Voltage Range: 170 V – 520 V AC (50/60 Hz)

• Response Time: <500 ms typical

• Operating Temperature: –40 °C to +70 °C

• Excitation System: SHUNT or AREP type

• Protection: Built-in over-excitation and thermal protection

• Compatibility: Suitable for Leroy Somer TAL and LSA series alternators, and equivalent generator models