Overview
The MX341 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
- ±1% Voltage Regulation — Stable output with PMG isolation from non-linear loads
- 2-Phase Sensing — Improved motor starting performance
- PMG-Powered — Independent excitation source for superior stability
- Sustained Short Circuit Current — Enhanced fault tolerance
- Soft Start Ramping — 3-second smooth voltage buildup
- Under-Frequency Protection — Adjustable set point with linear roll-off
Technical Specifications
| Parameter | Value |
|---|---|
| Type | Analogue, 2-phase sensing, PMG-powered |
| Sensing Input | 190-264VAC, 1-phase, 2-wire |
| Power Input (PMG) | 140-220VAC, 3-phase, 3-wire, 3A/phase, 100-120Hz |
| Output Voltage | Max 120VDC |
| Output Current | Continuous 2.7A, Intermittent 6A for 10s |
| Min Field Resistance | 15 ohms |
| Regulation Accuracy | <±1% (with 4% engine governing) |
| Soft Start | 3 seconds ramp |
| UF Protection | Set point 95% Hz, slope 170% down to 30Hz |
| Overexcitation Shutdown | 75VDC, 10s delay |
| Operating Temp | -40°C to +70°C |
Compatibility
- Stamford Brushless Alternator Series
- Compatible with: Part.: MX341
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 Stamford HC/LC series 100-500kW PMG brushless generators.
Competitors R250 (Leroy Somer), MX342 (Stamford enhanced).
| Parameter | MX341 | R250 | MX342 |
| Brand | Stamford (UK) | Leroy Somer (France) | Stamford (UK) |
| Output Current | 4A cont. | 5A cont. | 4A cont. |
| Regulation | ±0.5% | ±0.5% | ±1% |
| Excitation Type | PMG 2-phase sensing | Self-excited or PMG | PMG 2-phase |
| Voltage Sensing | Built-in | Needs external R731 module | Built-in |
| Current Limiting | No | No | Yes |
| UF Protection | Yes | Yes | Yes |
| Installation Complexity | Low (no extra module) | Medium (needs R731) | Low |
| Price | $50-80 | $60-90 + R731 $50-100 | $55-85 |
Selection Advice The MX341 is the most widely used AVR in the Stamford 100-500kW power range. Its primary advantage is extremely simple installation — all sensing functions are built into one device with no external sensing module required. In contrast, the R250 has 1A more current but requires an additional R731 voltage sensing module, bringing total cost $60-110 higher with an extra installation step. The MX342 adds current limiting but does not support parallel operation. If current limiting is not critical, the MX341 is more economical. If the installer is the generator end user (not a professional electrician), the MX341 is the appropriate choice — lowest installation barrier.
