5.1.2. Speed control unit for governor system (DWC-2000 series speed control unit) z This speed control unit performs the electronic function of the engine governing system. The speed control unit senses the pulses from the magnetic speed sensor, compares them with the speed control unit's set point and supplies the appropriate current output to the actuator to control the engine's fuel system. z An integral, independent single element speed switch is provided internally which can be used to initiate engine shutdown in the event that an overspeed condition is reached. The performance of the speed control unit is fast and responsive in either isochronous or droop operation.
z Adjustments are provided for: operating speed, idle speed, overspeed shutdown setting, droop, run ramp, crank ramp, starting fuel, speed ramping and two performance adjustments(gain and stability). All adjustments are accessible from the front cover. The primary features of the DWC-2000 Series speed control unit are the engine STARTING FUEL and SPEED RAMPING adjustments. The use of these features will minimize engine exhaust smoke experienced prior to attain engine operating speed.
The speed control unit also includes other features such as adjustable droop and idle operation, inputs for accessories used in multi-engine or special applications and protection against battery supply, loss of speed sensor and overspeed signaling are built-in to provide engine reverse voltage polarity, transient voltages and accidental short circuit of the actuator. Loss of shutdown.
Battery DROOP SWITCH - + A E F K L Droop Adjustment Pulse/second = Hz D Output Circuit Actuator PID Controller FV Converter C B Starting Fuel Adjustment IDLE Speed Adjustment Speed Adjustment Gain Adjustment 0.45 mm Speed Ramp Adjustment Stability Adjustment M G CONTROL UNIT EC8OM007 Maintenance of Major Components - 106 -