Overview
The AS480 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
- Continuous 4A Output — Handles mid-size alternator excitation demands with 10A intermittent peak capacity
- ±1% Regulation Accuracy — Maintains tight voltage control across full load range
- Soft Start Voltage Ramping — Smooth excitation buildup eliminates startup surges
- Selectable Sensing Input — 120VAC or 240VAC via jumper for flexible installation
- Over-Excitation Protection — Built-in safeguard against field overload conditions
- Under-Frequency Protection — Automatic voltage reduction during low engine speed events
Technical Specifications
| Parameter | Value |
|---|---|
| Sensing Input | 120VAC (95-132V) or 240VAC (190-264V), 1-phase 2-wire |
| Output Voltage | Max 90VDC at 207VAC input |
| Output Current | Continuous 4A, Intermittent 10A |
| Regulation Accuracy | <±1% RMS (with 4% engine governing) |
| Soft Start | Yes |
| Over-Excitation Protection | Yes |
Compatibility
- Stamford HC4, HC5 Series Alternators
- Compatible with generators 20-200 kVA range
- Compatible with: Part.: AS480, 45-0428
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 200kW+ high-performance generator sets.
Competitors
| Parameter | AS440 | AS480 | AS540 |
| Output | 4A | 4A | 4A |
| Regulation | ±0.5% | ±0.5% | ±0.5% |
| Control Type | Analog | Analog (upgraded) | Digital microprocessor |
| Communication | None | None | Yes |
| 3-Phase Sensing | Yes | Yes | Yes |
| Price | $70-100 | $80-120 | $150-250 |
Selection Advice The AS series is Stamford’s high-performance line, positioned above SX and MX. The AS440 is the best-value high-performance choice — same regulation as MX341 but with more comprehensive 3-phase sensing. The AS480 is the upgraded AS440. The AS540 is the digital high-performance model with communication interfaces for SCADA integration, suitable for smart power stations. For standard high-performance needs, choose AS440. For remote monitoring, choose AS540.
