Hobart 60CU20 Operation And Maintenance Manual With Illustrated Parts List page 85

OM-2226 / Operation and Maintenance Manual
60CU20 / Series 500062 / 400 Hz. Generator Set
b) Operational Test Procedures
(1) Start the engine in accordance with instructions in Section 1-3.
(2) Check operation of engine instruments; ammeter, coolant temperature indicator, oil pressure
gage and hour meter.
(3) Check engine idle speed. Should be 1000 +/- 25 RPM.
NOTE: A stroboscope may be required for this check.
(4) Again check for oil, fuel, and coolant leaks and correct any leaking condition
.
(5) Position switches and controls for automatic voltage regulation and power delivery as follows:
a Place regulated-diagnostic switch in "REGULATED" position.
b Place EF Bypass switches in "BYPASS / OFF" position.
c If the output voltage coarse adjustment potentiometer on the voltage regulator has been
disturbed, place the knob at mid-range position.
(6) Bring the engine up to rated speed, which also energize the generator, by pressing the "ENGINE
START" push button switch a second time. If the engine comes up to rated speed and a 115 V
voltage value appears on the voltmeter, the engine ECM and excitation circuits are functioning.
(7) After generator overhaul or repair, the Regulated/Diagnostic switch must be placed in the
"DIAGNOSTIC" position for 3 to 5 seconds to re-magnetize the exciter. Then return the switch to
the "REGULATED" position after voltage has built-up.
(8) Observe frequency meter. If engine speed is properly set, frequency should read 400 Hz.
(9) Observe voltmeter. Use output fine voltage coarse adjustment potentiometer to adjust voltage to
115 V AC.
(10) Check adjustable voltage range.
a Observe voltmeter and turn output voltage coarse adjustment potentiometer to full clockwise
position. Maximum voltage should be 134 volts or higher.
NOTE: If voltage should decrease when regulator potentiometer is turned clockwise, it indicates that
internal wiring in the voltage regulator is incorrect. Replace complete voltage regulator assembly.
b Observe voltmeter and turn regulator potentiometer knob to full counterclockwise position.
The minimum voltage should be 95 volts or lower.
(11) Position load bank switches, etc., to apply a light load to the generator.
May 2, 2013 Chapter 2-3
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