Woodward 9905-798 | 2301A Series Electronic Load Sharing & Speed Controller for Generator Sets

Description

Product Overview

Key Technical Specifications

• Power Supply:
  • Low-voltage model: 20–40 VDC (for smaller prime movers).
  • High-voltage model: 88–132 VAC (50/60 Hz) or 90–152 VDC (for larger turbines/generators).
• Input Signals:
  • Accepts 4–20 mA current signals (from CTs/scalar sensors) and 0–10 VDC voltage signals (from PTs/potentiometers).
  • Supports up to 12 programmable digital inputs (e.g., start/stop commands, fault signals).
• Output Signals:
  • 4–20 mA analog output (for driving actuators/valves).
  • Up to 6 programmable relay outputs (for alarms, breaker control, or load shedding).
• Speed Control Range: 500–12,000 RPM (configurable via software).
• Load Sharing Accuracy: ±1% (ensures balanced load distribution among parallel generators).
• Protection Functions:
  • Overspeed protection (independent of main control system).
  • Reverse power protection (prevents generator from motoring).
  • Loss-of-speed-signal protection (triggers alarm/shutdown if speed sensor fails).
• Operating Temperature: -20°C to +70°C (-4°F to +158°F) (suitable for indoor/outdoor industrial environments).
• Certifications: CE, UL (compliant with international industrial safety standards).

  

  WOODWARD 9905-001-G

Field Application & Problem Solved

• Grid penalties (e.g., fines for frequency deviations).
• Equipment damage (e.g., generator overheating, turbine blade fatigue).
• Downtime (e.g., generator tripping, process interruptions).

1. Precision Speed Regulation: Using a PID (Proportional-Integral-Derivative) control algorithm, it maintains the prime mover’s speed within ±0.1% of the setpoint—critical for grid compliance (e.g., 50/60 Hz frequency stability).
2. Intelligent Load Sharing: It communicates with other 2301A series controllers (via a shared bus) to distribute load evenly among parallel generator sets. For example, if one generator’s load exceeds 80%, the 9905-798 automatically shifts load to idle generators—maximizing efficiency and preventing overloads.
3. Fault Tolerance: Built-in protection functions (e.g., overspeed, reverse power) trigger immediate alarms or shutdowns if abnormal conditions are detected—minimizing downtime and equipment damage.

• Power Generation: Controlling standby generators during peak demand or grid outages.
• Cogeneration: Balancing electrical and thermal loads by paralleling turbines with driven equipment (e.g., compressors).
• Marine Propulsion: Synchronizing shipboard generators for auxiliary power generation.

Installation & Maintenance Pitfalls (Expert Tips)

1. Power Supply Compatibility:
   • Verify that the input voltage (20–40 VDC or 88–152 VDC/VAC) matches the model’s rating. Mismatched voltage can damage the internal circuitry—use a multimeter to check the power supply before installation.
2. Signal Wiring Best Practices:
   • Use shielded cables for all input/output signals (to reduce electromagnetic interference).
   • Separate power cables from signal cables (to prevent noise coupling).
   • Ensure proper grounding (all shields should be connected to a single-point ground).
3. Programming & Calibration:
   • Use Woodward’s menu-driven software (via a PC or handheld programmer) to configure settings (e.g., speed setpoints, load sharing ratios).
   • Calibrate the controller using a precision frequency meter (to ensure speed accuracy).
4. Regular Maintenance:
   • Inspect the 9905-798 annually for signs of wear (e.g., cracked casings, loose connections).
   • Clean the controller’s connectors with isopropyl alcohol (to remove dirt/debris that can cause communication failures).
   • Test protection functions (e.g., overspeed trip) quarterly to ensure they work properly.

     

     WOODWARD 9905-001-G

Technical Deep Dive & Overview

1. Speed Sensing: The controller receives speed signals from a magnetic pickup (MPU) or encoder (mounted on the prime mover’s shaft). These signals are converted to a digital format for processing.
2. PID Control: The digital signal is compared to the desired speed setpoint. The PID algorithm calculates the error (difference between actual and setpoint speed) and adjusts the output signal to the actuator (e.g., fuel valve)—bringing the prime mover’s speed back to the setpoint.
3. Load Sharing: For parallel generator sets, the 9905-798 communicates with other controllers via a shared bus. It exchanges load data and adjusts each generator’s output to ensure balanced distribution.

Final Notes