Woodward 9907-018 Speed Control Load Sharing Relay

Description

Product Introduction & Engineering Value

Few things expose governor instabilities like sudden load changes on an isolated microgrid. The Woodward 9907-018 is built exactly for this tough environment, operating as a dedicated, high-speed analog processor that maintains precise engine rpm regardless of line transients.

I rely on the 2301A series because its analog circuit paths eliminate the boot times and software bugs that can plague modern digital governor systems. It acts as a hardwired control loop, correcting speed deviations through direct potentiometer tuning to deliver immediate actuator response when a heavy motor starter cycles on.

Technical Specifications

Field Application & The “Trench” Experience

An offshore supply vessel suffered from severe frequency oscillations every time its primary thrusters were pushed to full power. The old governor card was slow to adjust, causing the auxiliary diesel units to throw reverse-power faults. We swapped the old card out for the 9907-018, adjusted the dynamic potentiometers using a digital oscilloscope, and set up the load-sharing line between the engines. The analog loop responded instantly to changes, leveling out the engine recovery profile and keeping the vessel’s electrical bus rock-solid during heavy maneuvering.

• Prime Power Diesel Synchronization: Paralleling multiple medium-speed engine blocks sharing a single distribution bus.
• Mechanical Drive Variable Speed Tracking: Running dedicated industrial pump stations via remote 4-20 mA speed settings.
• Legacy Steam Turbine Governing: Driving fast-acting hydraulic valve positioners on legacy process steam equipment.

Transparency SOP: QA & Testing

Our thorough functional test protocol ensures your unit arrives ready to work in the field:

1. We clean and inspect the chassis frame, terminal barriers, and potentiometer adjustment screws.
2. We connect an MPU simulator to verify the module tracks frequency cleanly from 500 Hz up to 10 kHz without signal dropouts.
3. We test the actuator drive loop across its full 0–160 mA operating range into a simulated 35-ohm coil load to ensure steady response.
4. We run the unit through an extended thermal burn-in under full load to catch and eliminate component failures.

9907-018

9907-018

The Veteran’s Tech Trap Guide

⚠️ THE ACTUATOR BIAS TRAP: Never adjust the top potentiometers using anything other than a properly sized insulated tuning tool. Using an uninsulated metal screwdriver can cause minor shorts against the chassis wall if you slip, which can fry the analog operational amplifiers and lock the actuator drive output at a dangerous 160 mA maximum fuel position.

PRO TIP: When upgrading an older 2301 system to this 2301A model, double-check your power supply wiring. The 9907-018 is a low-voltage unit that requires 20-40 VDC. Accidentally connecting it to a 115 VAC line meant for a high-voltage governor module will instantly ruin the internal input stage components.

Dynamic FAQ

• Q: Can this 9907-018 module be configured for a 0 to 200 mA actuator loop instead of 0 to 160 mA?
  • A: No. This model has a hardware limit of 0 to 160 mA. For high-current actuators, you will need to add an external driver amplifier card or choose a different 2301A part number.
• Q: My engine hunts at idle but smooths out under load. Which screw adjusts this?
  • A: This behavior points to a dynamic loop imbalance. You need to adjust the Gain and Reset dials together to dial in the engine’s response rate when it is running without a load.
• Q: What is the lowest magnetic pickup signal voltage that this unit can reliably track?
  • A: The input circuit requires at least 1.0 VAC RMS at your lowest cranking speed to overcome internal filter thresholds and register engine rotation.
• Q: Are your New Surplus 9907-018 modules shipped in original factory packaging?
  • A: Yes. Our New Surplus units ship in their original boxes with factory markings, accompanied by a copy of our certified bench-test report and a full 1-year warranty.