^ZVAF
SX421
Description
Earlier shunt-excited variant, still serviced on older sets.
Did you know
- The Stamford SX421 Automatic Voltage Regulator (AVR) was introduced by Newage International Limited, with documentation dating back to at least 2002. It is a component of the excitation system for brushless generators.
- The SX421 is an analogue AVR within Stamford's product line, sitting alongside other analogue models like the SX460, AS440, AS480, AS540, MX341, MX342, and MX321. It offers more advanced features than the SX440, including three-phase RMS sensing and over-voltage protection.
- The SX421 is chosen for its high-performance three-phase sensed voltage regulation, ensuring stable and consistent power delivery across varying load conditions. It is designed for both prime power and standby applications, providing reliable starting and voltage establishment from residual levels.
| Model | Sensing Input | Excitation Power Source | Voltage Regulation | Over-voltage Protection |
|---|---|---|---|---|
| SX421 | Three-phase sensed (170-250 V ac max, 50-60 Hz nominal) | Derived directly from generator terminals | +/- 0.5% RMS | Provides tripping signal for external circuit breaker |
| SX460 | Single-phase, two-wire (95-132VAC or 190-264VAC) | Derived directly from generator terminals | <±1% RMS | Not specified as integrated |
| AS440 | Single-phase, two-wire (95-132VAC or 190-264VAC) | Derived directly from generator terminals | <±1% RMS | Not specified as integrated |
| MX341 | Two-phase sensed (170-250 V ac max) | Permanent Magnet Generator (PMG) | <±0.5% RMS | In-built protection against sustained over-excitation |
| MX321 | Three-phase sensed (190-264VAC) | Permanent Magnet Generator (PMG) | <±0.5% RMS | Internal de-excitation system and tripping signal for external circuit |
Competitive Models
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Code map
^Z V A F │ │ │ └── Model: SX421 │ │ └───── Make: Stamford (Newage / Cummins Gen Tech) │ └──────── Equipment: Automatic Voltage Regulator └─────────── System: Automation Spares