Test 11 - Excitation Wiring; Test 12 - Check Brush Leads; Test 13 - Check Brushes & Slip Rings - Generac Power Systems 4451 & 4986 Repair Manual

TEST 11 - EXCITATION WIRINg

PROCEDURE:
1. Set a voltmeter to measure resistance.
2. Disconnect Connector C1. See Page 17 for connector location.
3. Locate the male side of the connector located on the bottom
of the control panel. See Figure 6-19. Connect one meter
test lead to Pin 6 Wire 2, it may be helpful to connect a small
jumper lead to the individual pin. Disconnect Wire 2 from the
Excitation Circuit Breaker (CB1). Connect the other meter test
lead to Wire 2 . See Page 17 for Excitation Circuit Breaker loca-
tion. Continuity should be measured.
4. Unplug the six pin connector at the Voltage Regulator.
5. Locate the male side of the C1 connector located on the bot-
tom of the control panel. Connect one meter test lead to Pin
7, Wire 6. It may be helpful to connect a small jumper lead to
the individual pin. 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. Continuity should be measured.
RESULTS:
1. If continuity was not measured in any of the steps repair or
replace wire.
2. If all steps pass refer back to flow chart.

TEST 12 - CHECk bRUSH LEAdS

PROCEDURE:
1. Set a voltmeter to measure resistance.
2. Disconnect Connector C1. See Page 17 for connector location.
3. See Figure 6-18. Connect the meter test leads across Wire 4
(Pin 11) and Wire 0 (Pin 12) at the C1 connector female side.
Be careful not to damage the pin connectors with the test
leads, use paper clips - do not force probes into connectors.
Rotor resistance should be measured approximately 7-14
ohms. If resistance is measured proceed to Step 6. If no resis-
tance is measured continue.
4. Remove the control panel assembly to access the brushes.
See Figure 6-21. Connect one meter test lead across Wire
4 (Pin 11) at the C1 connector female side. Be careful not to
damage the pin connectors with the test leads, use paper clips
- do not force probes into connectors. Connect the other meter
test lead to Wire 4 at the brush assembly. Continuity should be
measured. If INFINITY is measured repair or replace Wire 4.
5. Connect one meter test lead across Wire 0 (Pin 12) at the
C1 connector female side. Be careful not to damage the pin
connectors with the test leads, use paper clips - do not force
probes into connectors. Connect the other meter test lead to
Wire 0 at the brush assembly. Continuity should be measured.
If INFINITY is measured repair or replace Wire 0.
6. Unplug the six pin connector at the Voltage Regulator.
7. Locate the male side of Connector C1 located on the bottom
of the control panel. See Figure 6-19. Connect one meter test
lead to Pin 11 Wire 4. Connect the other meter test lead to Wire
4 at the six pin connector previously removed from the Voltage
Regulator. See Figure 6-11. Be careful not to damage the pin
connectors with the test leads. Continuity should be measured.
If continuity is not measured repair or replace Wire 4 between
the C1 connector and the six-pin Voltage Regulator connector.
8. Connect one meter test lead to Pin 12 Wire 0. See Figure 6-19.
Connect the other meter test lead to the ground terminal in the
control panel. Continuity should be measured. If continuity is
not measured repair or replace Wire 0 between the C1 connec-
tor and the ground terminal.
RESULTS:
1. Repair or replace wiring/terminals as needed.
2. If no faults are found refer to flow chart.
4
Figure 6-20. – Brush Leads
TEST 13 - CHECk bRUSHES & SLIP RINgS
PROCEDURE:
1. Gain access to the brushes and slip rings.
section 6
Diagnostic tests
0
Page 45