Onan EGH - Engine Speed

ENGINE SPEED
I
50 STANDARD
The engine governor maintains a constant engine
speed under various load conditions to limit variations
in generator output voltage and frequency. Engine
speed variations directly affect the frequency and to a
lesser extent the output voltage of the generator. An
increase in engine speed
will cause a corresponding
increase in generator frequency and a decrease in
engine speed
will cause a corresponding decrease in
frequency. Voltage is held fairly constant by the voltage
regulator when small variations in engine speed occur.
Contact with moving parts can cause
b@!%l severe personal injury. Keep
clothing, jewelry, hands, and fingers clear when work-
ing on the generator set
A hot muffler and other generator set
lliEFSl components can cause severe
burns. Always allow the generator set to cool before
touching any components.
Engine Speed Check and Adjustment
Disconnect all loads from the generator set. An accurate
frequency meter should be connected to the generator
output receptacle. Check and adjust the engine speed
as follows:
1. Start the engine. Make sure the speed control lever
is in the high speed position on Standard models
and that the Idlematic is
Off on Pro models. Operate
the generator set with no-load until it is warm. Refer
to Figure
4-7.
2. Check the no-load frequency for a normal reading
of 63.5 Hz
+ or - 0.5 Hz (3780 to 3840 RPM).
3.
If an abnormal reading is measured, adjust the
speed as follows:
4.0 STANDARD MODELS
HIGH SPEED
ADJUSTMENT
FS-1828-1
Standard Models - Move the speed control lever to a
position between the high and low speed settings.
Adjust the high speed screw by turning it counterclock-
wise
to increase engine speed or clockwise to decrease
engine speed.
4.0kWSfandardModels:Onefull turn of the adjustment
screw will change the frequency approximately
1-1 /4
Hertz. Do not turn the adjustment screw more than 2
turns.
5.0 k WSfandard Models: One full turn of the adjustment
screw
will change the frequency approximately4 Hertz.
Do not turn the adjustment screw more than 112 turn.
After making an initial adjustment, move the speed con-
trol lever to the high speed setting and recheck fre-
quency. Repeat this process until a normal no-load
speed (63.5 Hz
+ or - 0.5 Hz) is obtained.
Pro Models - Set the idlematic control to On. Adjust the
high speed screw by turning
it clockwise to increase
engine speed or counterclockwise to decrease engine
speed. One full turn of theadjustment screw
will change
the frequency approximately 3.7 Hertz. Do not turn the
adjustment screw more than
314 turns. After making an
initial adjustment, set the Idlematic control
to Off and
recheck frequency. Repeat this process until a normal
no-load speed (63.5 Hz
+ or - 0.5 Hz) is obtained.
6
J
5.0 STANDARD MODELS
L
PRO MODELS WITH
IDLEMATIC
M-1876
FS-1830
FIGURE 4-7. ENGINE SPEED ADJUSTMENT
4-6