Overview
The R449 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 for sensitive loads
- 7A Continuous Output — 180VDC max for large PMG-excited alternators
- PMG Excitation — Isolated from non-linear load effects
- 120/240VAC Selectable — Jumper-configurable sensing
- Wide Frequency — 10-100Hz for variable-speed operation
- Large Alternator Ready — LSA51.2, LSA52.3, LSA53.2, LSA54.2
Technical Specifications
| Parameter | Value |
|---|---|
| Sensing Input | 120/240VAC jumper selectable |
| Output Voltage | Max 180VDC |
| Output Current | Continuous 7A |
| Regulation Accuracy | <±0.5% |
| Frequency | 10-100 Hz |
| Excitation Type | PMG-excited |
| UF Limitation | k=1 |
| Voltage Setting Range | ±5% |
Compatibility
Leroy Somer alternators. Compatible with: R449.
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 47-49 series PMG-excited large generator sets.
Competitors R438 (self-excited), R450 (next generation).
| Parameter | R449 | R438 | R450 |
| Excitation | PMG permanent magnet | Self-excited | Self-excited/PMG |
| Output Current | 7A | 4A | 6A |
| Build-up Dependency | No residual voltage needed | Needs 6VAC residual | Needs residual or PMG |
| Critical Power Suitability | Best | Good | Excellent |
Selection Advice The R449 is the PMG permanent magnet excitation specialist. The key advantage of PMG: completely independent of generator residual voltage for build-up — even if the generator has been idle for a year with zero residual voltage, the PMG can independently generate excitation current to start the generator. This makes the R449 the recommended choice for hospitals, data centers, airports, and other critical power applications requiring 100% guaranteed start success. 7A high current is also among the highest in its group.
