Woodward 8512-070 Hydraulic Governor with SMM40 Motor

Woodward 8512-070 Hydraulic Governor with SMM40 Speed Adjusting Motor

The Woodward 8512-070 is a hydro-mechanical governor designed for isochronous and droop speed control of marine propulsion engines, auxiliary diesel generator sets, and industrial prime movers. Equipped with the integral SMM40 synchronous/stepper speed-adjusting motor (split-field synchronizing motor), this unit enables precise remote electric speed setting, automated frequency synchronization, and accurate load-sharing across multi-generator busbars.

Utilizing a self-contained hydraulic oil reservoir and a dual-rotation spur gear pump with internal spring-loaded check valves, the 8512-070 produces steady, high-response hydraulic work output (nominally rated at 8 ft-lb / 10.8 N·m or 12 ft-lb output options depending on internal power cylinder bore) without relying on external engine lube oil circuits. This closed hydraulic circuit insulates the pilot valve, rotating ballhead, and precision flyweight carrier from engine lube oil contamination, ensuring governing stability under fluctuating sea-state loads.

Technical Details

Key Features

1. Self-Contained Hydro-Mechanical Circuitry: Protects sensitive internal metering valves from fuel contamination and carbon soot present in external engine crankcase oils.
2. Integrated SMM40 Speed Setting Motor: Allows seamless interface with main switchboard auto-synchronizers, PMS (Power Management Systems), and remote bridge/control room telegraphs.
3. Dual-Direction Gear Pump: Automatic check-valve system allows direct mounting to either clockwise or counter-clockwise rotating camshaft takeoffs without internal gear swapping.
4. Adjustable Isochronous to Droop Ratios: Front-panel knob facilitates linear adjustment from 0% isochronous mode (constant speed independent of load) up to 10% droop for proportional load sharing.
5. Internal Mechanical Stops & Limit Switches: SMM40 motor features pre-set travel limit switches, preventing motor burnout and linkage binding at minimum and maximum rack excursions.

Applications

• Marine Auxiliary Generating Sets: Speed and frequency stabilization for medium/high-speed marine generator sets running on MGO, MDO, or heavy fuel oil (HFO).
• Direct-Drive Marine Propulsion Engines: Constant and variable-speed prime mover control connected via reduction gearboxes to controllable-pitch propellers (CPP).
• Islanded Power Generation Systems: Load-sharing across isolated microgrids, offshore drilling rigs, and marine platforms requiring synchronous bus tie operation.
• Industrial Pump and Compressor Drives: Hydrocarbon and high-pressure water pumping installations where mechanical failsafe operation is critical during electrical blackouts.

Engine & Equipment Compatibility

• Wärtsilä: 20, 26, and Vasa 32 series
• MAN Energy Solutions: L16/24, L21/31, L23/30, and L28/32 auxiliary gensets
• Caterpillar / MaK: M20, M25, and 3500/3600 marine series
• Yanmar: 6N18L, 6EY18AL, 6N21L, and 8N21 series
• Daihatsu: 5DK-20, 6DK-20, 6DL-20, and 6DL-22 series
• Bergen Engines: K-G, B-G, and C-series diesel and lean-burn gas units

Part Number Cross-References

• Woodward Governor MPN: 8512-070, 8512070, 8512-070-A
• Equivalent / Parent Series: Woodward UG-8 Dial, UG-8 Lever, UG-8 with SMM40 Motor
• Related Motor Assemblies: Woodward SMM40 (24VDC / 110V / 220V variants)
• Engine Builder Specific Cross-References:
  • MAN B&W: 047.8512-070
  • Wärtsilä: PAAE034211 / 18512070
  • Daihatsu: D8512070-Z

Frequently Asked Questions

What is the primary difference between a standard Woodward UG-8 and the 8512-070 model?

The Woodward 8512-070 is an advanced configuration within the UG-8 family, factory-integrated with an SMM40 electric speed adjusting motor. While standard UG-8 governors depend exclusively on manual dial or direct pneumatic pressure caps for speed changes, the 8512-070 enables automated synchronization and remote speed variation via the ship’s electrical Power Management System (PMS) or manual switchboard pushbuttons.

How do I troubleshoot an SMM40 motor that fails to raise or lower engine speed?

First, verify control voltage across Terminal 1 (Common) and Terminal 2 (Raise) or Terminal 3 (Lower) using a multimeter. If voltage is present at the terminal block, check the internal travel limit microswitches located under the motor top cover. If the governor speed adjustment dial has reached its mechanical physical stop, the microswitch will naturally open the circuit to prevent motor winding damage. If the dial is midway and no actuation occurs, inspect the motor internal spur gears for debris or internal slip clutch disengagement.

Can the Woodward 8512-070 be mounted horizontally?

No. The 8512-070 contains an internal, unpressurized oil reservoir that depends on gravity for pump suction and proper air release through the top breather. The governor must be installed vertically within 10° of vertical alignment to maintain appropriate oil level above the internal accumulator ports and prevent oil aeration.