Be prepared to make an emergency shutdown when starting the engine, turbine, or other type of prime mover, to protect against runaway or overspeed with possible personal injury, loss of life, or property damage.
Prime mover will not
start. Actuator not
moving to start-fuel
position (cont.).
LOW IDLE SPEED setting may be
too low.
Adjust LOW IDLE SPEED potentiometer cw.
Minimum Fuel contact open. See
"MINIMUM FUEL CONTACT" in
Chapter 2.
If voltage exceeds 3 volts, the
switch or wiring is faulty.
Check switch at terminal 3. Minimum-fuel contact
must be closed for normal operation. Check for 0 to
3 Vdc from terminal 2 (+) to 3 (–) on low-voltage
controls. (Between terminals 6 (+) and 3 (–) on
high-voltage controls.
MPU not supplying signal to
control.
Check MPU wiring for proper connection, check
shields for proper installation.
Magnetic pickup may be open-circuited or shorted.
Check resistance with the leads disconnected from
the control. Resistance should be about 100 to 300
W.
Prime mover will not
start. Actuator not
moving to start-fuel
position.
Terminals 11 and 12 are open. Verify that terminals 11 and 12 are jumpered if
optional external speed trim is not used.
Check the voltage from terminal 11 (+) to 12 (–). It
should be less than 2 volts.
Faulty speed trim potentiometer. With power OFF, check speed-trim potentiometer
with an ohmmeter.
Faulty 2301A Speed Control. Replace unit.
Prime mover
overspeeds only on
starts.
Ramp adjustment. Increase RAMP TIME (cw). This decreases
acceleration rate (from low idle to rated.)
RATED SPEED setting too high. Set RATED SPEED as described in Chapter 3.
Amplifier adjustment. 2301A may be adjusted for sluggish operation,
causing overspeed on start. Slowly adjust GAIN for
fastest stable response. RESET may be adjusted
too low. Increase RESET setting.
Engine is malfunctioning. Verify that the fuel rack is not binding and the
linkage is properly adjusted. Determine if the fuel
rack is quickly following the actuator input voltage.
Verify proper operation of overspeed protection
devices to determine if a shutdown is occurring
without an overspeed condition.
2301A Speed Control. If the control does not cut back the actuator voltage
when the speed setting is completely ccw the
2301A control may be faulty, or may have the
wrong speed range. If the voltage is cut back,
(increased on reverse acting controls) look for a
problem in the linkage or actuator.
Prime mover
overspeeds after
operating at rated
speed for some time.
Prime mover. Check for proper operation of prime-mover fuel
system. If actuator moves toward minimum fuel
during overspeed, problem is in fuel system.
MPU and 2301A control. Check MPU voltage at speeds above idle (at least
1.0 Vrms). If MPU fails and the switch at terminal 4
is closed, the 2301A will call for maximum fuel.
2301A dynamics adjustment. Control the prime mover manually at rated speed
and adjust the RATED SPEED setting fully ccw. If
the output voltage is not zero, replace the control.
(Voltage should be about 7 volts for 0-200 mA
reverse acting controls or maximum current time
actuator resistance for controls of other ratings.)
Prime mover has
momentary speed
change when
adjusting GAIN.
GAIN adjustment made too
quickly.
Make GAIN adjustment slowly. Momentary speed
change when adjusting GAIN is normal.
