Generac Power Systems 53187 - Manual (Page 56)

SECTION 1.9
OPERATIONAL TESTS AND ADJUSTMENTS
Voltage Regulator Adjustment (Contln>
ued)
UNITS W ITH 15 INCH STATOR (CONT’D);
14. Turn OFF all electrical loads and check the voltage
regulator lam ps at no-load.
15. W hen all adjustm ents have been com pleted, let the
engine run at no-load for a few m inutes to stabiiize
internal engine-generator tem peratures.
16. Shut the engine dow n.
I
PARTI
THE REVOLVING FIELD AC GENERATOR
Overspeed Shutdown Adjustment
GENERAL;
NP series generators are equipped w ith an auto­
m atic shutdow n system w hich w ill stop the engine in
the event of an overspeed. Shutdow n w ill occur auto­
m atically w hen AC frequency (engine speed) exceeds
approxim ately 69-71 Hertz (2070-2130 rpm ). Adjust­
m ent of the overspeed shutdow n setting is required
w hen the unit’s engine control circuit board is replaced.
Figure 5. Engine Control Circuit Board
ADJUSTMENT PROCEDURE:
To adjust the overspeed shutdow n setting, proceed
as follow s;
1. On the engine controi circuit board, turn the OVER­
SPEED
SHUTDOW N POTENTIOMETER counter­
clockw ise until it just contacts its stop. DO NOT
FORCE.
2. Connect an accurate AC frequency m eter across the
generator’s AC output leads.
3. Start the engine, let it stabilize and w arm up.
4. Use the injection pum p throttle lever to SLOW LY
increase engine speed untii the frequency m eter reads
69-71 Hertz.
5. Hold the thrtottle at 69-71 Hertz and SLOW LY turn
the OVERSPEED SHUTDOW N POT clockw ise. W hen
the engine shuts dow n, overspeed setting is correct.
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