Woodward 9905-973 Load Sharing & Speed Control – Reliable Governing for Engine and Generator Sets

The Woodward 9905-973 is a proven load sharing and speed control module for engines and gensets that need stable governing and smooth paralleling. It’s commonly used as a direct replacement within the 2301A-style control family. From my experience, teams choose it when they want consistent isochronous speed control, clean kW load sharing, and a straightforward analog interface that technicians already understand. You might notice that it integrates neatly with standard magnetic pickups and 0–200 mA proportional actuators, so retrofits are typically fast and low risk.

Company’s Order Placement Process and Guarantees

• Warranty: 365 days
• Lead time: 1 week if in stock; no more than one month at the latest
• Payment: 50% advance payment; full payment before delivery
• Express options: FedEx, UPS, DHL

Key Features

• Isochronous speed control: Keeps engine speed steady under changing loads, which typically helps stabilize voltage and frequency on gensets.
• kW load sharing: Analog load-sharing line for smooth paralleling of multiple generator sets without hunting.
• MPU speed sensing: Accepts standard two-wire magnetic pickup input for precise speed feedback.
• Actuator drive (0–200 mA): Drives Woodward-style proportional electric actuators for accurate fuel/steam valve positioning.
• Analog setpoint inputs: Supports remote speed/reference signals (commonly 4–20 mA or low-voltage analog, depending on configuration).
• Rugged, field-proven design: In many cases these units run for years with minimal attention, which reduces unplanned downtime.
• Drop-in retrofit: Familiar terminal layout and wiring philosophy keep commissioning straightforward for maintenance teams.

Technical Specifications

Application Fields

This controller is used on diesel and gas engines for power generation, marine auxiliaries, oil & gas skids, industrial compressors, and pumping systems. It’s especially practical where multiple gensets are paralleled and operators want stable frequency and clean load division without moving to a fully digital platform. On brownfield projects, the 9905-973 often fits existing wiring practices and reduces rework.

Advantages & Value

• Reliability: Field-proven analog design that typically handles electrical noise better in heavy industrial environments.
• Compatibility: Works with standard MPUs and Woodward-type proportional actuators; easy to integrate with legacy switchgear load-sharing lines.
• Reduced downtime: Straightforward commissioning and familiar tuning pots shorten outage windows.
• Cost control: Keeps the existing governor/actuator philosophy, avoiding costly system redesigns.
• Supportable: Technicians can diagnose with a multimeter—no special software needed.

A maintenance supervisor from a port power house told us the swap from an aged 2301A to a 9905-973 “was essentially a wire-by-wire move; tuning took half a shift, and the sets shared within a few kW at first parallel.”

Installation & Maintenance

• Cabinet & environment: Mount in a clean, dry, ventilated panel. Keep clear of vibration and high-heat sources.
• Power & grounding: Use a stable 24 VDC supply with proper fusing. Bond the control ground at a single point; avoid ground loops.
• Wiring practices: Shielded twisted pair for the MPU. Route low-level signal wiring away from high-current conductors and contactors.
• Actuator loop: Verify 0–200 mA range compatibility and stroke calibration on the actuator linkage.
• Tuning & checks: Set speed, gain, stability, and droop/isochronous as required. Validate no-load to full-load transitions and paralleling behavior.
• Routine maintenance: Periodically inspect terminals, re-torque screws, clean dust, and confirm speed feedback quality. Record setpoint positions after service.

Quality & Certifications

• Certifications: Typically CE compliant; many configurations are UL/cUL recognized. RoHS status may vary by build—confirm on the nameplate or datasheet.
• Manufacturing quality: Produced under established quality systems (commonly ISO 9001 within the Woodward supply chain).
• Warranty: 365-day warranty as stated above.

Recommended Supporting Components

• Magnetic Pickup (MPU): Standard two-wire passive MPU for engine gear teeth sensing.
• Proportional Actuator: Woodward-style 0–200 mA electric actuator sized to the engine fuel/steam valve.
• Protective hardware: Proper fusing, terminal blocks, and a clean 24 VDC power supply module.

If you’re replacing an older governor or standardizing a mixed fleet, the 9905-973 seems to be a sensible, low-friction option. Send over a photo of your current panel and actuator nameplate, and we can double-check signal compatibility before you place the order.