TP-6881 7/1586 Section 5 Component Testing and Adjustment
5.10 Governor System
The governor system consists of an electromechanical
stepper motor (actuator) and an engine speed
detection/feedback circuit. The RDC2 or DC2 controller
controls the governor system operation. See Section 7,
Wiring Diagrams, for the governor connections.
5.10.1 O peration
The frequency of the alternator output is determined by
the speed of the engine. A two-pole alternator is driven
at 3600 rpm to provide 60 Hertz. The engine speed is
maintained by an electronic governor system that
consists of an embedded controller and electric
actuator (stepper motor).
The governor system is controlled by the generator set
controller. The controller provides regulated power to
the bidirectional stepper motor a ctuator, which is linked
to the carburetor throttle arm.
The engine runs at a reduced speed during the warmup
and cooldown idle period of the cycle exercise. During
this time, the rotor field is not energized and the
generator will not produce voltage. When not producing
voltage, the generator will not be subject to large
changes in engine loading, so the governor response is
dramatically slowed to decrease throttle linkage wear
and fuel consumption. The response is also slowed
during cooldown and fault cooldown for the same
reason.
The engine speed adjustment setting in SiteTech allows
adjustment of the engine speed for testing purposes.
See Section 5.11.2. If the engine is hunting or surging,
do not adjust the engine speed. Test the governor
operation as described in Sections 5.10.3 and 5.10.4.
Then adjust the governor gain to stabilize the engine
operation if necessary before adjusting the speed. See
Section 5.11.1.
5.10.2 Initial Checks
Hazardous voltage.
Can cause severe injury or death.
Operate the generator set only when
all guards and electrical enclosures
areinplace.
Moving parts.
WARNING
Servicing the generator set when it is operating. Exposed
moving parts can cause severe injury or death. Keep
hands, feet, hair, clothing, and test leads away from the belts
and pulleys when the generator set is running. Replace
guards, screens, and covers before operating the generator
set.
The factory sets the electronic governor. Under normal
circumstances the electronic governor requires no
further adjustment. Verify that the governor stepper
motor moves smoothly and steadily during operation. If
the engine operates erratically, check the following
connections and conditions before adjusting the
governor.
D Verify that the electrical connections are clean and
tight.
D Verify that the battery connections are clean and
tight.
D Check for a loose or worn stepper motor/throttle shaft
coupling. Replace the shaft and bushing every 500
hours of engine operation.
D Check the carburetor for dirt, grime, or
misadjustment. Check for a loose mixer assembly.
D Check the idle-adjustment screw. The screw should
not prevent the throttle plate from closing completely.
D Check the throttle linkage for any binding, dirt,
damage, or other visible problems.
D Observe the stepper motor operation. The stepper
motor should open the throttle while cranking, and
pull back after speed feedback is detected.
D Check for electronic governor faults. The fuel shutoff
solenoid deenergizes and the generator set shuts
down under the following conditions:
D Closed throttle
D Engine overspeed
D Broken fuel shutoff solenoid lead
D Broken stepper motor leads (erratic performance)
D Failed actuator linkage (erratic performance)
D Check the fuel supply pressure and the fuel supply
system for leaks, blockages, and/or failed system
components (regulators, valves, etc.). See
Section 5.13, Fuel Systems.
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