Description
Product Introduction & Engineering Value
The Woodward 9905-726 belongs to the 2301A family of electronic speed/load controls. Available technical listings identify this specific variant with a 4–20 mA speed-setting input, making it suitable for applications where an external analog signal establishes the desired engine or turbine speed.
The replacement decision should not be based solely on the 9905-726 number. Verify the control power, magnetic-pickup configuration, actuator current requirement, speed-reference scaling, and load-sharing arrangement against the existing installation. Those interfaces determine whether the replacement will actually operate correctly in the governor system.
Technical Specifications
| Parameter | Specification |
|---|---|
| Manufacturer | Woodward |
| Part Number | 9905-726 |
| Control Family | 2301A |
| Control Type | Electronic/digital speed controller |
| Speed Setting Input | 4–20 mA |
| Actuator Output | 0–200 mA |
| Speed Sensing | Magnetic pickup input |
| Control Power | Low-voltage DC configuration reported for this variant |
| Speed / Load Function | Speed regulation and load-control applications |
| Load Sharing | Supported within applicable 2301A system configurations |
| Typical Prime Movers | Diesel engines, gas engines, and turbine-driven equipment |
| Adjustment | Front-panel adjustment controls are reported for the 2301A hardware |
| Protection | Starting-fuel limitation and speed-control limiting functions are documented for related 2301A configurations |
A current product listing specifically identifies 9905-726 with a 10–40 VDC control-power supply, 0–200 mA actuator output, and 4–20 mA speed-setting input. Because these specifications are from a secondary source rather than an accessible Woodward datasheet for this exact part number, they should be confirmed against the unit’s nameplate and original Woodward documentation before installation.
Field Application & the “Trench” Experience
A generator technician is troubleshooting a diesel genset that reaches rated speed manually but fails to maintain the commanded operating point when the external speed reference is enabled. The existing controller is identified as 9905-726. Before replacing it, the technician records the magnetic-pickup wiring, actuator current requirement, control-power voltage, and 4–20 mA scaling.
The important detail is the analog reference. If the replacement controller is configured for a different speed-reference input, simply transferring the existing wires will not reproduce the original control behavior. The commissioning team therefore verifies the signal at the controller terminals before applying the actuator output.
Specific application scenarios
- Diesel generator speed control — regulating engine speed from an external 4–20 mA reference.
- Gas-engine generator sets — maintaining commanded speed and supporting load-control functions.
- Industrial turbine control — providing electronic speed regulation where the applicable actuator and pickup arrangement matches the controller.
- Generator load-sharing systems — integrating speed/load control with compatible Woodward synchronizing and load-sharing equipment.
Woodward’s SPM-A documentation confirms that Woodward synchronizers can interface with 2301A load-sharing controls, illustrating the broader control architecture in which 2301A-family equipment can operate.
9905-726
Transparency SOP: QA & Testing
For New Surplus 9905-726 inventory, a meaningful acceptance procedure should go beyond checking whether the LEDs illuminate.
1. Identity
Verify the Woodward nameplate, complete part number, revision, and serial information.
2. Physical condition
Inspect the enclosure, terminals, adjustment controls, PCB area, and mounting points for evidence of prior service or damage.
3. Power verification
Confirm the intended control-power range before applying external power. Do not assume a controller with the same 2301A family designation has the same power configuration.
4. Signal testing
Where suitable test equipment is available, simulate the magnetic-pickup signal and verify the response to the 4–20 mA speed-reference input.
5. Actuator-output testing
Verify the output response against the controller’s documented actuator requirements before connecting the actual fuel or steam actuator.
6. Documentation
Record the test setup, input values, output values, condition, and warranty status.
One secondary-market listing currently states a 12-month warranty for 9905-726, but warranty terms are supplier-specific and should be written into the purchase order rather than assumed from a marketplace listing.
The Veteran’s Tech Trap Guide
⚠️ Trap #1 — Do not confuse 9905-726 with an SPM-A synchronizer.
Some marketplace listings classify the part as an SPM-A synchronizer or load-sharing module, but the available 9905-726 listings identify it primarily as a 2301A digital/electronic speed controller. Woodward’s actual SPM-A documentation lists different SPM-A part numbers such as 9905-001, 9905-002, and 9907-028.
⚠️ Trap #2 — Check the actuator current before energizing the output.
A reported 0–200 mA actuator output is significant. Do not connect an actuator until its required drive current and the controller output configuration have been verified against the actual unit documentation.
PRO TIP: Record the existing 4–20 mA signal at minimum, rated-speed frequency from the magnetic pickup, and actuator current before removing the old controller. Those three measurements can save substantial commissioning time.
⚠️ Trap #3 — Verify the exact power-supply variant.
Secondary sources report a low-voltage DC configuration for 9905-726, while Woodward has produced multiple 2301/2301A control configurations with different power arrangements. Never apply power based solely on a seller’s generic 2301A description.
Dynamic FAQ
What is Woodward 9905-726?
9905-726 is identified in current secondary-market documentation as a Woodward 2301A-family digital/electronic speed controller, used for prime-mover speed and load-control applications.
What is the speed-reference input?
Available documentation for the specific 9905-726 identifies a 4–20 mA speed-setting input.
What actuator output does 9905-726 provide?
The available specification identifies a 0–200 mA actuator output. Confirm the actual controller revision and actuator requirements before commissioning.
Is 9905-726 the same as a Woodward SPM-A synchronizer?
No. The SPM-A is a separate synchronizer product family. Woodward’s SPM-A documentation identifies part numbers such as 9905-001/9907-028 and 9905-002/9907-029.
Can a New Surplus 9905-726 be used as a direct replacement?
It can be considered only after confirming the control-power configuration, magnetic-pickup range, 4–20 mA reference scaling, actuator requirements, and existing load-sharing/synchronizing arrangement. Physical similarity alone is insufficient.
What should the supplier provide for a New Surplus unit?
Request clear photographs of the nameplate, part number and revision, serial information, physical-condition statement, functional-test report, warranty period, and RMA terms. “New Surplus” should be clearly distinguished from Used and Refurbished stock.
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