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Governors America Corp. © 2021 Copyright All Rights Reserved
ESD5550-5570 Series Speed Control Unit
1-2021-E1
PIB1003
UnSaTISfacTorY Performance
SYmPTom
normaL reaDInG
ProBaBLe caUSe
Engine Overspeeds
1.
Do Not Crank. Apply DC power to
the governor system.
After the actuator goes to full fuel, disconnect the speed sensor at Terminal
C & D. If the actuator is still at full fuel-speed then the speed control unit is
defective.
2.
Manually hold the engine at the
desired running speed. Measure
the DC voltage between Terminals
A(-) & F(+) on the speed control
unit.
1. If the voltage reading is 1.0 to 2.0 V DC:
•
SPEED adjustment is set above desired speed
•
Defective speed control unit
2. If voltage reading is above 2.0 V DC then check for:
•
actuator binding
•
linkage binding
3. If the voltage reading is below 1.0 V DC it may be a defective speed
control unit
4. Check if Gain is set too low.
Overspeed Shuts Down En-
gine After Running Speed is
Reached
•
Speed adjustment set too high.
•
OVERSPEED set to close to running speed.
•
Actuator or linkage binding.
•
Speed control unit defective.
Overspeed Shuts Down En-
gine Before Running Speed
is Reached
Check impedance between
Terminals C & D. Should be 160
to 1200 Ω
OVERSPEED set too low. Adjust 5-6 turns CW.
Erroneous speed sensor signal. Check wiring.
Actuator does not energize
fully
1.
Measure the voltage at the battery
while cranking.
If voltage for a 12 V DC system is less than 7 V DC, or for a 24 V DC system is
less than 14 V DC, replace the battery if weak or undersized
2.
Momentarily connect Terminals A
and F. The actuator should move
to the full fuel position.
•
Actuator or battery wiring in error
•
Actuator or linkage binding
•
Defective actuator
•
Fuse opens. Check for short in actuator or harness.
Engine remains below
desired governed speed
1.
Measure the actuator output, Ter-
minals A & B, while running under
governor control.
If voltage measurement is within 2 V DC of the battery supply voltage level,
then fuel control is restricted from reaching full fuel position, possibly due to
mechanical governor, carburetor spring, or linkage interference.
SPEED parameter set too low
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SySTEM TROUblESHOOTINg (CONTINUED)
