Test 3- Test Excitation Circuit Breaker; Test 4 - Fixed Excitation Test/Rotor Amp Draw - Generac Power Systems 4451 & 4986 Repair Manual

section 6
Diagnostic tests
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Figure 6-8. – 20/30 Amp Breaker Test Points
TEST 3 - TEST EXCITATION CIRCUIT bREAkER
PROCEDURE:
1. With the generator shut down for at least two minutes, locate
the Excitation Circuit Breaker in the control panel. Disconnect
wires from the breaker, to prevent interaction.
2. Set a volt meter to measure resistance.
3. Connect the VOM test probes across the circuit breaker termi-
nals. The meter should read CONTINUITY.
RESULTS:
1. If circuit breaker tests bad (meter reads "OPEN") then proceed
to Test 4 and replace the breaker after completing Test 4.
2. If circuit breaker is good, go on to Test 4.
162
2
Figure 6-9. - Testing Excitation Circuit Breaker
Page 38
20/30A
PROCEDURE:
C.B.
*NOTE: If the generator is not producing AC
Power, loss of governor control may occur caus-
ing an overspeed or extremely high RPM condi-
tion. If this condition occurs manually control
throttle (60Hz /3600 RPM) to perform test.
1. Unplug the six pin connector at the Voltage Regulator.
2. Disconnect Wire 14 from the Resistor (R1).
3. Connect a jumper wire between the removed end of Wire 14
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4. Set voltmeter to measure AC voltage
5. Disconnect Wire 2 from the Excitation Circuit Breaker and con-
6. Set Idle control switch to OFF.
7. Start the generator.
8. Measure the output voltage across Wire 2 and Wire 6 and
AC Voltage across Wires 2 and 6 = _____________
TEST 4 - FIXEd EXCITATION TEST/
ROTOR AMP dRAW
and Wire 4 where it is soldered at the Diode (D1). See Figure
6-10.
14
14
4
4
14
WIRE 14
REMOVED
14
JUMPER LEAD
4
4
Figure 6-10. – Jumper Lead From Wire 14 to Diode
nect one meter test lead to it. Connect the other meter test lead
to Wire 6 located in the six pin connector previously removed
from the Voltage Regulator. Be careful not to damage the pin
connectors with the test leads. See Figure 6-11.
record the results.
R1
D2
R1
D2