Stamford MX321-2 Automatic Voltage Regulator (AVR)
The Stamford MX321-2 (Order Number: E000-23212/1P) is a high-performance three-phase thyristor-type Automatic Voltage Regulator (AVR). It forms the core of the excitation system for brushless generators in industrial and commercial power generation applications, providing precise voltage control under variable load conditions.
Key Specifications
Model: MX321-2 (Part Number: E000-23212/1P)
Type: Three-phase sensed, Thyristor (SCR) based AVR
Power Input (PMG): 170-220 VAC, 3-phase, 3A
Sensing Input: 170-250 VAC, 1- or 3-phase
Excitation Output (DC): Max 120 VDC
Output Current: 4 A continuous, 7 A for 10 seconds (intermittent)
Regulation Accuracy: < ±0.5% RMS (with 4% engine governing)
Frequency Range: 50-60 Hz (selectable via terminal links)
Built-in Protections: Under-speed (UFRO), Over-excitation, Over-voltage, Short circuit current limiting, Loss of sensing, LAM
Additional Features: Three-phase RMS detection, Voltage ramp / Dwell (soft-start), Parallel/Reactive droop compensation
Weight: 500 grams
Field Resistance: Minimum 15 Ohms
Advanced Technology and Protection
The MX321-2 is powered by the generator's PMG (Permanent Magnet Generator), ensuring immunity to waveform distortion. It includes Under-Frequency Roll-Off (UFRO) to protect the exciter during engine startup and over-excitation/over-voltage shutdown prevents damage to the rotor or field windings.
Voltage Regulation
The MX321-2 utilizes true RMS sensing, providing accurate voltage measurement even with non-linear loads. The regulation accuracy is typically within 1% of the setpoint under steady-state conditions.
Industrial Applications
The AVR is used in prime power and standby generator sets, as well as marine and gas extraction applications.
Conclusion
The Stamford MX321-2 ensures stable operation of generator sets across a wide range of temperatures and electrical environments, with built-in over-excitation and over-protection features.
