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Phone: +86 16626708626Description
Key Technical Specifications
- Function: Speed-set biasing and automatic breaker closure for generator paralleling
- Input Voltage: 115 VAC or 230 VAC RMS, selectable
- Voltage Tolerance: ± 10%
- Frequency Range: 50 to 60 Hz (bus and generator)
- Phase Angle Window: ± 10 degrees
- Power Consumption: 5 W maximum
- Weight: 3.72 lbs
- Voltage Matching: Not equipped — this unit handles frequency and phase only, not voltage matching
- ⚠️ Output Contact Rating, Enclosure Dimensions, Mounting Style: Not confirmed from an OEM datasheet in this pass — verify against the Woodward SPM-A manual before installing, especially the breaker-close contact rating.
Product Introduction
The Woodward 9905-001 SPM-A Synchronizer biases an offline generator’s speed set point until its frequency and phase match an already-running generator on an isolated multi-engine bus. Once the two are within its ±10 degree phase window, it issues a contact closure to bring the breaker in automatically.
It runs on selectable 115 or 230 VAC input across a 50 to 60 Hz range, with adjustable dynamics to tune the response to the specific engine governor it’s paired with. Plants and marine propulsion systems running legacy multi-genset configurations use this when the original synchronizer fails and a like-for-like replacement is faster than a control system redesign.
Troubleshooting Quick Reference
| Symptom | Possible Cause | Relevance to this Part | Quick Check Method | Recommendation |
|---|---|---|---|---|
| Generator never reaches sync window | Synchronizer fault or governor not responding to bias signal | ✅ High | Verify the bias output is reaching the governor/actuator | Confirm governor response before condemning the synchronizer |
| Breaker never closes even at matched frequency/phase | Output contact failure or wiring fault | ✅ High | Check continuity on the breaker-close contact circuit | Test the contact output directly before replacing the module |
| Unstable or hunting speed bias signal | Dynamics adjustment mismatched to the governor | ❌ Low | Review dynamics settings against the engine/governor combination | Retune dynamics before assuming module failure |
| No power/response from unit at all | Input voltage fault or internal power supply failure | ✅ High | Measure input voltage at the terminals (115/230 VAC) | Confirm incoming power before replacing the synchronizer |
| Breaker closes but generators fall out of sync immediately after | Voltage mismatch between generators | ❌ Low | Check voltage regulators on both generators | This unit doesn’t handle voltage matching — check elsewhere |
If the fault doesn’t isolate cleanly to the synchronizer, send your governor model and wiring diagram to technical support before pulling the unit — a lot of “bad synchronizer” calls turn out to be governor or breaker wiring issues.
9905-001
9905-001
Frequently Asked Questions (FAQ)
Does this unit also match generator voltage, or just frequency and phase?
Just frequency and phase. The 9905-001 isn’t equipped to process voltage matching — if your generators are drifting apart on voltage, that’s a separate voltage regulator issue, not something this synchronizer handles.
Can I select either 115V or 230V input on the same unit?
Yes, the input voltage is selectable between 115 and 230 VAC RMS. Confirm which setting your specific unit is configured for before wiring it in — don’t assume based on the part number alone.
Why is this cheaper than a new unit, and is used stock reliable?
Woodward has discontinued this model, so most of what’s available is used, remanufactured, or new surplus rather than fresh manufacture. A properly remanufactured unit with a real warranty is a reasonable bet; ask your supplier what testing was done and what warranty backs it.
Will a remanufactured unit perform the same as new?
A properly remanufactured 9905-001 should meet original spec, but “remanufactured” varies by shop. Ask specifically what was tested and replaced, not just “fully functional” as a blanket claim.
Is this part still supported by Woodward?
No — it’s discontinued by the manufacturer. Budget accordingly for lead time on sourcing, and consider whether a repair path makes more sense than chasing new-old-stock if your current unit is repairable.
Can I swap this in without retuning anything?
Don’t assume that. The dynamics adjustments are tuned to your specific engine and governor combination — verify and reset them after installation rather than assuming the previous unit’s settings carry over identically.
