TP-6844 1/13 Section 5 Component Testing and Adjustment 71
5.5.2 Volts/Hz Slope
The Volts/Hz setting for the voltage regulator performs
the following functions on the generator:
• Improve stability in transient loading conditions
• Minimize hunting that may be caused by switching
loads
Higher values of a Volts/Hz Slope will cause the
Voltage Correction Factor to shift more on a sudden
change in the output voltage. Lower values will cause
a lower shift. High values in the Volts/Hz Slope may
cause the 6VSG to become unstable.
5.5.3 Voltage Regulator Gain
The 6VSG uses a closed loop voltage correction
controller to correct for long-term temperature drift.
The voltage controller acts by changing the correction
factor that the desired speed is multiplied by to
accommodate changes in the alternator over time and
with temperature. If the voltage is constant (within 4%
of a 1.6 second average) and stable (<2% change in
0.1 seconds), the voltage correction controller will
decrease the correction factor if the voltage is high and
increase the correction factor if the voltage is low.
The Voltage Regulator Gain determines the rate at
which the factor is updated. At a gain of 1, the voltage
correction will change the correction factor by 0.1%
every 102.5 seconds. At a gain of 255, the voltage
correction will change the correction factor by 0.4%
every 0.5 seconds. The default setting for the Voltage
Regulator Gain is 128. If the transient response is
slow, use SiteTech to increase the Voltage Regulator
Gain setting.
Note: Increasing the gain too much may cause the
output to oscillate. If adjustment does not
improve the transient response, return the gain
parameter back to the factory setting and
continue with troubleshooting procedures.
Note: This closed loop voltage compensation is not
active when the controller is in current limiting
mode; the last known voltage correction factor is
used.
5.6 Governor System
The governor system consists of an electromechanical
stepper motor (actuator) and an engine speed
detection/feedback circuit. The VSC controller
controls the governor system operation.
See Section 7, Wiring Diagrams, for the governor
connections.
5.6.1 Operation
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 actuator, which is
linked to the carburetor throttle arm.
If the engine is hunting or surging, test the governor
operation as described in Sections 5.6.3 and 5.6.4.
Then adjust the governor gain to stabilize the engine
operation if necessary. See Section 5.6.5.
5.6.2 Initial Checks
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.
• Verify that the electrical connections are clean and
tight.
• Verify that the battery connections are clean and
tight.
• Check for a loose or worn stepper motor/throttle
shaft coupling. Replace the shaft and bushing
every 500 hours of engine operation.
• Check the carburetor for dirt, grime, or
misadjustment. Check for a loose mixer assembly.
• Check the idle-adjustment screw. The screw should
not prevent the throttle plate from closing
completely.
• Check the throttle linkage for any binding, dirt,
damage, or other visible problems.
• Observe the stepper motor operation. The stepper
motor should open the throttle while cranking, and
pull back as the engine approaches the target
speed.
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