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3. Key Technical Specifications
| Parameter | Specification Value |
| Manufacturer | Woodward |
| Part Number | 9905-726 |
| Control Series | 2301A Load Sharing & Speed Control |
| Power Supply Voltage | 18–40 VDC (24 VDC nominal) |
| Power Consumption | 5 W nominal |
| Speed Sensor Input | Magnetic Pickup Unit (MPU) signal (1.0 to 30 VRMS) |
| Control Modes | Isochronous or Droop speed control |
| Actuator Output Signal | 0–200 mA output signal to hydraulic/electric actuators |
| Operating Temperature | −40°C to +85°C (−40°F to +185°F) |
| Signal Inputs | Speed trim, SPM synchronizer, load sensor interface |
| Mounting Architecture | Base-mount chassis with terminal strip connections |
4. Product Introduction & Supply Chain Strategy
The Woodward 9905-726 is a 2301A series load sharing and speed control module designed for precise speed control of prime movers, including diesel engines, gas engines, and steam turbines. It accepts inputs from magnetic pickup units (MPU) and load sensors to manage actuator position, ensuring tight frequency regulation and proportional load sharing across parallel generator sets.
This product is a Brand New Surplus unit. It is not used, not pulled from a decommissioned plant, and not refurbished. All modules undergo rigorous quality verification to ensure OEM-level reliability. Stocking this module as New Surplus ensures immediate operational protection against unexpected prime-mover control failures without necessitating a complete governor system overhaul. Refurbished speed controllers frequently suffer from drift in analog potentiometer trims, aged electrolytic capacitors, and solder joints weakened by thermal cycling—factors that cause frequency oscillation or engine overspeed events. Securing factory-fresh surplus guarantees total circuit integrity, stable actuator drive current, and extended service life.
9905-726
5. Installation & Configuration Guide
1.Pre-Installation Preparation & Safety:Enforce LOTO and prepare terminal wiring diagrams.
Implement full Lockout/Tagout (LOTO) on the engine or turbine starter system to prevent accidental engine cranking. Wear a grounded wrist strap to prevent static discharge to the internal circuit board. Take photos and label every wire connected to the existing terminal strip before removal.
2.Legacy Unit Removal:Disconnect field wiring and unbolt baseplate.
Systematically unscrew and disconnect wires from the terminal block, including MPU inputs, actuator outputs, and 24 VDC supply lines. Remove the four corner mounting bolts holding the chassis to the panel enclosure and set the old controller aside.
3.Mechanical Mounting & Potentiometer Matching:Mount module and replicate potentiometer settings.
Bolt the new 9905-726 unit securely into the panel chassis. Prior to wiring, measure and record the physical potentiometer positions (Rated Speed, Gain, Stability, Actuator Compensation) on the original unit and set the new 9905-726 potentiometers to identical baseline settings. Connect field wiring strictly according to the terminal pinout diagram.
4.Power-On & Dynamic Tuning:Verify MPU voltage and adjust stability loop.
Apply 24 VDC control power and verify power supply polarity. Crank the engine and measure the MPU AC voltage signal to ensure it exceeds 1.5 VRMS. Once the engine starts, fine-tune the Gain and Stability potentiometers to achieve a fast, bump-less response to step load changes without speed hunting.
6. Firmware/Software Versions & Upgrade Notes
- Hardware Architecture: The 9905-726 is an analog control system that does not rely on software or flash firmware, offering immune execution against firmware-induced software bugs or protocol timeouts.
- Actuator Compatibility: Ensure the actuator drive output jumper configuration matches your specific actuator coil resistance (e.g., 0–200 mA output range).
- Replacement Notes: When replacing older 2301 series speed controls with the 2301A (9905-726), verify terminal block cross-references, as pin numbering and terminal layout changed between generations.
7. Frequently Asked Questions (FAQ)
Q: Is this Woodward 9905-726 controller a New Surplus unit or a repaired unit?
A: This unit is 100% Brand New Surplus stock. It has never been placed into active service on an engine or generator set, has zero backplane wear, and retains original OEM manufacturing quality.
Q: Why should I buy New Surplus instead of a cheaper refurbished governor control?
A: Speed controllers are critical safety items for prime movers. Refurbished analog boards often feature aged capacitors and worn potentiometers that cause frequency drift or unstable load sharing. A speed controller failure can lead to an unmonitored overspeed event or severe mechanical engine damage, costing exponentially more than the initial savings on a refurbished component.
Q: Can this unit handle both single-unit speed control and parallel load sharing?
A: Yes. The 9905-726 can operate in Isochronous mode for single-unit operation, Droop mode for paralleling with an infinite bus, or Isochronous Load Sharing mode when connected via load sharing lines to other compatible Woodward controls.
Q: How do I resolve engine speed hunting after installing the new unit?
A: Speed hunting is typically caused by incorrect Gain and Stability potentiometer settings or low MPU signal voltage. Adjust the Gain counter-clockwise to reduce sensitivity, and turn the Stability clockwise to dampen response until speed stabilizes under no-load and full-load conditions.
Q: What warranty is supplied with this New Surplus Woodward unit?
A: This Woodward 9905-726 unit comes with a full 1-year replacement warranty, ensuring complete functional reliability for your power generation system.
