ENGINE
SPEED
Generatorfrequency is in direct ratio to engine speed,
which is controlled by the governor.
A Roosa-Master governor is standard equipment on
the DYC generator set. High speed and low speed
limit stops are set at the Onan testing facility and
normally do not require furtheradjustment, therefore
if your set is used on continuous standby service, the
governor may never need to be touched. If however
the unit is used frequently, adjustment may be
required due to wear of internal components. This
adjustment is achieved by backing off the high speed
stop screw. Screw in the low speed adjusting screw
until the generator output frequency meter reads 60 ;
hertz (generator on load). Turn in the high speed,
adjusting screw until it bottoms; secure the locknuts.
HIGH
SPEED
ADJUST
IDLE
ADJUST
•GOVERNOR
FIGURE 24. ROOSA-MASTER GOVERNOR
Governor sensitivity is adjusted by rotating an exter-
nal knurled knob at the rear of the injector pump
housing.
Turning inward (clockwise) shortens gover-
nor control spring making it less sensitive
i
thereby
increasing speed droop. Turning outward (coun-
terclockwise) has opposite effect. Adjustment can be
made with engine running. The speed droop is set at
the Onan plant tq give a regulation of 3 percent to 5
percent from no-ioad to full-load.
When using the generator frequency meter to deter-
mine engine speed, multiply frequency by 30 to
calculate engine speed.
Example: 30 x 61 (hertz) = 1830 rpm.
Adjust engine speed to 1800 rpm for 60 hertz sets and
1500 rpm for 50 hertz sets,at full
load.
28
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