Woodward 8511-282 Governor with Motor

Woodward Part No. 8511-282 Hydraulic Speed Governor with Synchronizing Motor

The Woodward Part No. 8511-282 Governor with Motor is a mechanical-hydraulic speed droop governor engineered specifically for diesel engines, gas engines, and small steam turbines driving generators, pumps, and compressors. Believed widely across marine auxiliary gensets and land-based industrial cogeneration setups, this assembly features an integrated reversible electric speed-setting (synchronizing) motor mounted directly onto the governor head.

The mechanical flyweight and pilot valve assembly provides direct, instantaneous compensation for transient load swings, while the precision speed-setting motor allows remote switchboard frequency trimming, automatic synchronizer intervention (e.g., via Woodward SPM-A or digital power management systems), and seamless active load sharing (kW balancing) across paralleled alternators. Designed to operate using either self-contained hydraulic fluid or engine-lubricated oil systems, Part No. 8511-282 delivers high reliability, stable governing stiffness, and drift-free operation even in high-vibration maritime machinery spaces.

Model Details

• Manufacturer: Woodward, Inc. (USA)
• Model Designation: SG / PSG Series Mechanical-Hydraulic Governor with Speed Setting Motor
• Manufacturer Part Number (MPN): 8511-282 (Alternative format: 8511282)
• Sub-Assembly / Motor Drive Configuration: Top-mounted reversible bi-directional PMDC/AC synchronizer gear motor with internal limit switches and friction clutch assembly.

Compatibility

• Daihatsu: DL-16, DL-19, DL-20, DL-22, DL-26, DK-20, DK-26 auxiliary genset lines.
• Yanmar: S165, S185, M200, M220, T220, HAL, LA/RAL-series marine generator engines.
• Wärtsilä / Sulzer: Auxiliary engines including W20, Vasa 22, and earlier diesel genset platforms.
• MAN B&W / Holeby: 23/30, 28/32, and L16/24 auxiliary power packages.
• Caterpillar: 3406, 3412, 3508, 3512, and 3516 marine and industrial packages configured for mechanical-hydraulic governing with remote sync.
• Cummins: KTA19, KTA38, KTA50 generator packages with mechanical governor drive pads.
• Steam Turbines: Elliott, Terry, Dresser-Rand, and Coppus small-frame steam turbine drives for lube oil, ballast, and boiler feed pump applications.

Part Number Cross-References

• Woodward Part Numbers: 8511-282, 8511282, 8511-202, 8511-204, 8511-211, 8511-174, 8511-894.
• OEM Cross-References: Fits engine manufacturer part allocations matching Woodward SG/PSG/UG speed-droop mechanical-hydraulic assemblies with DC electric synchronizer motors.

Frequently Asked Questions

What is the primary function of the electric motor on the Woodward 8511-282?

The top-mounted electric motor is a reversible synchronizing motor designed for remote speed adjustment. It allows marine engineers and automated switchboards to fine-tune prime mover frequency from the central control room (CCR), synchronize the alternator with the busbar, and regulate load sharing between parallel-running engines.

Can the Woodward 8511-282 operate if the synchronizing motor fails?

Yes. The 8511-282 is fundamentally a mechanical-hydraulic governor. If electrical power to the synchronizing motor is lost, the governor will continue to maintain engine speed at its mechanical setpoint. The speed setting can be manually adjusted locally using the knurled knob or synchronizer dial on the governor housing.

Which hydraulic fluid should be used in the 8511-282 governor?

Use a clean, high-grade turbine oil or the engine’s recommended system lubricating oil conforming to ISO VG 32, 46, or 68. The oil must be clean and free of water, fuel dilution, or combustion soot to prevent sticking of the pilot valve plunger and check valves.

What is the recommended maintenance interval for this governor?

In marine auxiliary service, oil quality should be inspected every 500 operating hours. Complete overhaul, chemical de-sludging, internal seal replacement, and test-bench re-calibration are recommended every 12,000 to 16,000 running hours or during major 5-year class survey overhauls.

How do I troubleshoot governor speed hunting or instability?

Speed oscillations are usually caused by: (1) aeration in the hydraulic oil sump, (2) an improperly adjusted buffer compensation needle valve, (3) mechanical binding or excessive slack in the external fuel rack ball joints, or (4) contaminated, varnished oil jamming the pilot valve plunger. Ensure fluid is clean and linkages are free of friction before adjusting internal needle settings.