Description
Product Overview
The Woodward 9905-068 is a 2301A series standard-load-sharing-and-speed-control-module designed for industrial prime movers (e.g., diesel engines, gas turbines, steam turbines, generators). It serves as a core component in parallel power generation systems, enabling precise speed regulation and seamless load distribution across multiple generator sets.
As part of Woodward’s 2301A ecosystem, the 9905-068 is optimized for standard industrial environments (e.g., power plants, marine vessels, industrial facilities) where stable power output and efficient load management are critical. It is distinct from variants like the 9905-068C (reverse-acting design) and 9905-003-L (extended-temperature version), focusing on baseline performance with 24 Vdc input compatibility.
The 9905-068’s primary role is to maintain constant speed (isochronous mode) or adjust speed based on load (droop mode) while distributing electrical load evenly across paralleled generators—ensuring grid compliance, reducing equipment wear, and optimizing energy transfer.
Key Technical Specifications
Insights from Woodward 2301A series documentation and industrial supplier listings reveal the following parameters for the 9905-068:
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Input Voltage: 20–40 Vdc (nominal 24 Vdc) – compatible with global industrial DC power systems.
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Control Modes:
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Isochronous Mode: Maintains constant prime mover speed (±0.1% tolerance) for standalone/isolated bus operation.
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Droop Mode: Adjusts speed based on load (adjustable droop percentage, 0–10%) for parallel operation with other generators.
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Actuator Compatibility: Works with Woodward proportional actuators (e.g., EG-3P, PG-PL) for fuel/steam valve positioning.
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Operating Temperature: -25°C to +60°C (-13°F to +140°F) – suitable for indoor industrial environments (cooler than base 9905-003 due to 24 Vdc optimization).
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Certifications: CE, UL – compliant with international industrial safety standards.
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Dimensions: Compact form factor (~280 mm × 210 mm × 90 mm) – fits standard industrial cabinets.
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Weight: ~4.0 kg (8.8 lbs) – lightweight for easy handling during maintenance.
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Output Signal: 0–200 mA (sink) – drives actuators for real-time fuel/steam flow adjustment.
WOODWARD 9905-068
Field Application & Problem Solved
In industrial power systems, unstable speed (load/grid fluctuations) and uneven load distribution (parallel generators) lead to:
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Grid frequency deviations (penalties/equipment shutdowns).
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Generator overload (reduced lifespan).
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Inefficient energy transfer (higher fuel consumption).
The 9905-068 addresses these via:
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Precision Speed Regulation: Uses phase-locked loop (PLL) algorithms to maintain speed within ±0.1% of the setpoint (isochronous mode), critical for grid frequency stability (e.g., 50/60 Hz compliance).
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Automatic Load Sharing: Distributes load evenly across generators (±1% accuracy) in droop mode. Example: A marine vessel using 9905-068 reduced generator maintenance costs by 20% via balanced load distribution.
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Flexible Mode Switching: Supports isochronous (standalone backup power) and droop (parallel grid-connected) modes for diverse operations.
Typical Applications:
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Power Generation: Controlling steam/gas turbines in coal/gas-fired plants to stabilize grid frequency.
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Marine Propulsion: Synchronizing shipboard generators for auxiliary power with load sharing.
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Industrial Cogeneration: Balancing electrical/thermal loads in paper mills/refineries.
Installation & Maintenance Pitfalls (Expert Tips)
To ensure optimal performance of the 9905-068:
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Verify Power Supply: Confirm input voltage (20–40 Vdc) with a multimeter; mismatched voltage damages internal circuitry.
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Calibrate Speed Sensors: Use a precision tachometer to calibrate the prime mover’s magnetic pickup before installation (prevents speed deviations).
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Test Load Sharing Logic: Post-installation, use a resistive load bank to verify even load distribution (±1% accuracy).
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Annual Maintenance: Inspect for wear (cracked casings, loose connections) and clean connectors with isopropyl alcohol.
Technical Deep Dive & Overview
The 9905-068 operates on Woodward’s 2301A analog control platform (standard version, 24 Vdc-optimized):
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Signal Reception: Accepts inputs from:
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Speed sensor (magnetic pickup) monitoring prime mover shaft rotation.
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Load sensor (current transformer) measuring generator output current.
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Operator inputs (front-panel potentiometers) for speed setpoint/droop adjustment.
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Processing & Control: Analog circuitry with PID algorithms calculates fuel/steam flow. Isochronous mode maintains constant speed; droop mode adjusts for load.
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Output & Actuation: Sends 0–200 mA control signals to actuators (e.g., fuel valves) to regulate speed/load.
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Monitoring: Tracks overspeed, low oil pressure, and faults—triggering alarms via relay outputs.
WOODWARD 9905-068
Distinction from Variants:
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Unlike 9905-068C (reverse-acting, 0–200 mA output increases with decreasing input), the 9905-068 uses a forward-acting design (output increases with input).
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Narrower operating temperature (-25°C to +60°C) vs. 9905-003-L (-50°C to +85°C) due to 24 Vdc power optimization.
Final Notes
The Woodward 9905-068 is a reliable standard-load-sharing-and-speed-control-module for industrial prime movers in standard environments. Its 24 Vdc input compatibility, precise control, and ease of maintenance make it ideal for power generation, marine, and industrial applications.
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Upgrade Consideration: For reverse-acting designs, use 9905-068C; for extreme temperatures, use 9905-003-L.
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Maintenance: Follow Woodward’s 2301A Series Manual (Document # 2301A-OM-001) and consult certified technicians.
