How to troubleshoot a faulty speed trim potentiometer in a Woodward 9905 Control Unit?
To troubleshoot a faulty speed trim potentiometer, turn the power OFF and then check the speed trim potentiometer(s) using an ohmmeter.
What to check if the prime mover may not be receiving fuel as called for by the actuator voltage on my Woodward 9905 Control Unit?
Check actuator linkage to fuel controlling mechanism for any lost motion, binding, or excessive loading.
What to do if the adjustment of external speed trim causes instability on my Woodward Control Unit?
If adjustment of external speed trim causes instability, check potentiometer with ohmmeter for erratic behavior.
What to do if the LOW IDLE SPEED is set fully clockwise on my Woodward 9905?
Turn LOW IDLE SPEED setting counterclockwise with terminal 19 open. Be careful not to overtorque the pot.
What does it mean if the 2301A control does not cut back the actuator voltage on my Woodward 9905?
If the control does not cut back the actuator voltage [T20 (+) and T21 (–)] until the speed setting is completely counterclockwise, the 2301A control may be faulty, or may have the wrong speed range.
What does it mean if the Start Fuel Limit is inactive in my Woodward 9905 Control Unit?
On power up, the Fuel Limit can be bypassed if the MPU signal clears in less than 1 second.
What to do if the common + source is connected to the wrong terminal on my Woodward Control Unit?
If the common + source for contacts connected to terminals 14, 17, 18, and 19 is taken from terminal 16 instead of terminal 0, connect the + source for these terminals to terminal 0, not 16.
What to do if my Woodward 9905 Control Unit is faulty?
If you suspect a faulty control, consider replacing it.
What to do if the speed sensor signal isn't clearing the failed speed signal circuit on my Woodward Control Unit?
If the speed sensor signal isn't clearing the failed speed signal circuit, check the wiring for a proper connection.
What to do if my Woodward 9905 Control Unit prime mover will not start and the actuator isn't moving?
If your prime mover isn't starting and the actuator isn't moving to the start-fuel position, here are a few things to check: * First, ensure proper voltage from terminals 16 (+) to 15 (–). If it's a DC system and the polarity is incorrect, reverse the leads. * If there's voltage at control terminals 20 (+) and 21 (–) but the actuator remains still, inspect the wiring to the actuator for any opens or shorts. * Also, the start fuel limit might be set too low. Try turning the start fuel limit clockwise until the prime mover starts. * Make sure that actuator moves approximately 2/3 of its travel from no load to full load. * Check the magnetic-pickup output voltage at speeds above idle—it should be at least 1.0 Vrms.
Covers warnings about personal injury, overspeed protection, and proper equipment use.
Details potential equipment damage from misuse, battery handling, and electrostatic discharge.
Sets initial potentiometer values and guides the prime mover start-up process.
Adjusts GAIN, RESET, and ACTUATOR COMPENSATION for optimal system response.
Diagnoses issues like failure to start, actuator movement, and incorrect speed settings.
Addresses overspeed, excessive smoke, instability, and load sharing malfunctions.
General| Type | Control Unit |
|---|---|
| Operating Temperature | -40°C to 70°C |
| Storage Temperature | -40°C to 85°C |
| Humidity | 5 to 95% RH, non-condensing |
| Vibration | 2 g |
| Shock | 15 g, 11 ms half-sine |
| Input Voltage | 24 VDC (18 to 32 VDC) |
| Communication Protocols | Modbus TCP, Modbus RTU, Ethernet/IP |
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