Generac Power Systems GP Series Diagnostic Repair Manual page 32

Section 4 AC Diagnostic Tests
With generator shut down, disconnect all wires
2.
from suspected circuit breaker terminals to prevent
interaction.
See Figure 4-47. With the generator shut down,
3.
connect one meter test lead to one terminal of the
breaker and the other meter test lead to the other
terminal.
Set breaker to ON or CLOSED. Continuity should
4.
be measured.
Set breaker to OFF or OPEN. Infinity should be
5.
measured.
Results
If circuit breaker tests good, refer to flow chart.
1.
If breaker tests bad, replace.
2.
00.00
Figure 4-47. 50 Amp Breaker Test Points (on back of
breaker)
00.00
Figure 4-48. 20/30 Amp Breaker Test Points
Test 3 – Test Excitation Circuit
Breaker
Procedure
Shut down the generator and allow to cool for at
1.
least two minutes.
Locate the excitation circuit breaker in the control
2.
panel.
Disconnect wires from the breaker to prevent
3.
interaction.
Set DMM to measure resistance.
4.
Connect the DMM test probes across the circuit
5.
breaker terminals. Continuity should be measured.
Results
If circuit breaker tests bad (meter reads Open)
1.
pro-ceed to Test 4 and replace the breaker after
completing Test 4.
If circuit breaker is good, proceed to Test 4.
2.
26
A B
50A
C.B.
A B
014859
20/30A
C.B.
004588
162
2
Figure 4-49. Testing Excitation Circuit Breaker
Test 4 – Fixed Excitation Test/Rotor
Amp Draw Test
NOTE: If the generator is not producing AC power, this
can be a result of the field flash circuit to the rotor, rotor
circuit itself, DPE or power windings.
Procedure
See Figure 4-50. Disconnect Wires 11, 22, 4, 0, 6
1.
and 162 from the AVR.
6
162
Figure 4-50. AVR Wire Number Locations
Connect a jumper from Wire 0 to a good ground.
2.
Disconnect Wire 14 from resistor R1.
3.
See Figure 4-51. Connect a fused (7.5 amp)
4.
jumper wire between the removed end of Wire 14
and Wire 4 where it is connected to diode D2.
R1
FBR
Figure 4-51. Fixed Excitation Test/Rotor Amp Draw
00.00
4
22
0
11
015027
DB2
BA
Test
Diagnostic Repair Manual
004590
015028