Overview
The R731 from Leroy Somer is a three-phase voltage sensing module that works in conjunction with R250, R438, and R450 single-phase sensing AVRs. While standard AVRs only monitor 2 of 3 lines, the R731 adds monitoring for the third line, providing complete three-phase surveillance for critical applications.
Key Features
- Leroy Somer Brand — Genuine 3-phase sensing module
- Monitors All 3 Lines — Complete phase surveillance
- Works with R250 / R438 / R450 AVRs
- Critical Application Protection — Telecom, data centers, healthcare
- Analog Transistor Design
Technical Specifications
| Parameter | Value |
|---|---|
| Model | R731 |
| Brand | Leroy Somer (France) |
| Type | 3-Phase Sensing Module (Analog) |
| Sensing Method | Three 2VA single-phase transformers |
| High Voltage Tap | 340-480V ±5% (400V nominal) |
| Medium Voltage Tap | 200-240V ±5% (230V nominal) |
| Low Voltage Tap | 90-140V ±5% (110V nominal) |
| Voltage Adjustment | ±5% internal rheostat (P1) |
| Remote Voltage Adjust | 470Ω (±5%) or 1kΩ (±10%) rheostat |
| Current Sensing (CT) | For paralleling operation |
| Max Continuous Current | 1.3A (normal 1A, max 10A for 10s) |
| Droop Adjustment | Via CT input |
| Operating Temp | -40°C to +60°C |
Compatibility
Designed to work with Leroy Somer R250, R438, and R450 series AVRs. Provides three-phase sensing capability to single-phase sensing regulators.
Why Choose ZenixPower
- Leroy Somer Genuine — French-made quality
- Complete 3-Phase Monitoring — Detects issues on all lines
- Critical Application Ready — Telecom, data centers, healthcare, government
- Small Cost for Complete Protection — Monitors what standard AVRs cannot see
Specification Comparison
Important The R731 is not a standalone AVR — it is a voltage sensing module that must be used together with an R250, R438, or R448 AVR. It cannot function independently.








