Overview
The R250 is an Automatic Voltage Regulator (AVR) that maintains the generator output voltage within precise limits by controlling the exciter field current. It continuously samples the generator output voltage and adjusts excitation to compensate for load changes, engine speed variations, and temperature drift.
Key Features
- ±0.5% Regulation — Premium precision voltage control
- 5A Nominal Output — 63VDC max, 7A max for 10 seconds
- Transistor-Controlled — Fast response for demanding loads
- 85-139VAC Sensing — 50/60Hz selectable
- U/F Function (k=1) — Under-frequency protection built-in
- Wide Alternator Compatibility — LSA44.3, LSA46.3, LSA47.2, TAL44+
Technical Specifications
| Parameter | Value |
|---|---|
| Sensing Input | 85-139VAC (50/60Hz) |
| Output Voltage | Max 63VDC |
| Output Current | Nominal 5A, Maximum 7A for 10s |
| Regulation Accuracy | <±0.5% |
| Frequency | 10-100 Hz |
| Excitation Type | Self-excited shunt (transistor-controlled) |
| UF Function | 1.07 U/F |
| Fuse Protection | 8A |
| Response Time | 500 ms |
Compatibility
- Leroy Somer Alternator Series
- Compatible with: Part.: R250
Why Choose ZenixPower
- Tight Voltage Regulation — <±1% RMS regulation ensures stable generator output under 0-100% load transients
- Fast Response — Sub-0.5 second recovery time prevents voltage dips during motor starting and load switching
- Dual Excitation Compatibility — Self-excited shunt or PMG-powered configurations clearly labeled for correct selection
- Built-in Protections — Under-frequency roll-off, over-excitation limiting, and soft-start ramp as standard
- Drop-In Replacement — Terminal layout and mounting dimensions match STAMFORD, Leroy-Somer, Marathon, and Mecc Alte OEM AVRs
- Pre-Calibrated — Each AVR ships with factory-default potentiometer settings for immediate plug-and-play operation
Specification Comparison
Compatible Generators Leroy Somer LSA 44 series 30-200kW, or replacement for Stamford HC/LC series MX341.
Competitors MX341 (Stamford), R230 (Leroy Somer lower-spec).
| Parameter | R250 | MX341 | R230 |
| Brand | Leroy Somer (France) | Stamford (UK) | Leroy Somer (France) |
| Output Current | 5A cont. | 4A cont. | 4A cont. |
| Regulation | ±0.5% | ±0.5% | ±0.5% |
| Voltage Sensing | Needs R731 module | Built-in | Needs R731 module |
| Price (with module) | $110-190 | $50-80 | $90-160 |
Selection Advice The R250 is the strongest Leroy Somer mid-range model — 5A output is 1A more than MX341 (25% higher excitation capacity, still able to drive aged generators with increased field resistance). Important note: requires the R731 voltage sensing module — the R250 cannot function alone. The complete set (R250+R731) costs $110-190, more than double the MX341. Therefore, the R250 primarily serves customers requiring Leroy Somer OEM parts — warranty requirements, insurance specifications, or brand preference. Without brand preference, the MX341 is the more economical choice.
