Table 7-4.
Governor Malfunction Testing
PROBABLE
TERMINAL
NORMAL VALUE
CAUSE OF NON-NORMAL READING
CORRECTIVE ACTION
S
1.0 volt AC-RMS minimum
1.
Defective magnetic pickup.
1. Replace magnetic pickup.
while cranking.
2.
Gap too large between magnetic 2. Readjust magnetic pickup.
pickup and gear teeth.
3.
Improper or defective wiring 3. Replace wiring harness.
to the magnetic pickup.
K
L
N
R
10.1 + .20 volts DC while 1.
D.C. power not connected or 1. Connect D.C. power supply;
energized (Internal regu-
low battery voltage.
replace D.C. battery.
lated D.C. supply).
2.
Frequency trim potentiometer 2. Replace Control Unit.
shorted, grounded or miswired.
3.
Wiring error.
3.
Replace wiring harness.
4.
Defective control unit.
4.
Replace control unit.
Above 5.1 volts D.C. while 1.
Frequency adjust set too low. 1. Turn Frequency adjust screw
running. (inverse speed
clockwise.
error signal).
2.
Defective control unit.
2.
Replace control unit.
Above 5.1 volts is under
speed signal. Below 5.1
volts is over speed
signal.
On speed will indicate a
steady 5.1 volts.
8.5 to 9.5 volts D.C. while 1. Battery voltage may be too
1.
Charge D.C. battery; replace
cranking.
(Proportional
low while cranking.
D.C. battery.
actuator voltage).
2.
Defective Control Unit.
2.
Replace Control Unit.
2.5 volts D.C. maximum
1.
Output transistor open (defec- 1. Replace Control Unit.
while cranking. (Tran-
tive Control Unit).
sister voltage).
2.
Defective Actuator.
2.
Replace Actuator.
3.
Error in wiring to Actuator. 3. Replace Wiring Harness.
(6) Measure the center to center distance
between the hole in the fuel shutoff lever and
the hole in the actuator lever. Adjust the
rod ends on the threaded linkage rod so that the
center to center distance of the rod ends is the
same or slightly longer than that measured between
the fuel shutoff lever and the actuator lever.
(The 3.75 dimension is only approximate. If the
linkage is too short, the actuator lever will
attain its “no fuel” position [full clockwise]
before the fuel shutoff lever reaches its “no fuel”
position; the fuel shutoff lever will never reach
“no fuel”.
If the linkage is too long, the
actuator lever will reach its “full fuel” position
[full counterclockwise] before the fuel shutoff
lever reaches its “full fuel” position; full load
will not be reached.) It may be necessary to
readjust the position of the fuel shutoff lever
and/or the actuator lever to accommodate the
center to center distance of the rod ends and to
assure complete fuel shutoff and full load opera-
tion.
Fuel shutoff and actuator lever adjustments
will be covered under replacement procedures.
Tighten the nuts on the linkage rod against the
rod ends to maintain proper spacing.
(7) Return the generator set START-RUN-STOP
switch to the STOP position and the BATTLE SHORT
switch to the OFF position.
(8) Reconnect the actuator linkage rod end
to the engine fuel shutoff lever.
(9) Adjust the control unit gain control to
its approximate mid-range position.
(10) Adjust the control unit stability
control to its fully counterclockwise position.
(11) Adjust the generator set frequency
adjust potentiometer (pot) (located on the
generator set control panel) to mid-range.
(12) Using a small screwdriver, turn the
control unit frequency adjust screw (located on
the left side vertical face of the control unit)
at least 22 turns counterclockwise (opposite
increase arrow).
This will give the lowest
possible engine governed speed.
NOTE
Two people will be rewired to adjust the
control unit.
Ensure that the actuator
linkage rod and all levers are securely
fastened and move freely (without binding)
before operating the engine. Manually
overcome the actuator until adjustment of
the control unit is completed and the
governor is in control. Adjustment of
the control unit will be made with the
engine operating in a no-load condition.
(13) Start the engine, manually operating the
fuel shutoff lever.
Change 9
7-21
