Generac Power Systems CorePower 6/7 kW 60 Hz Diagnostic Repair Manual page 55

TRANSFER SWITCH
TEST 33 – CHECK N1 AND N2 WIRING
Discussion
A shorted Wire N1 or N2 to ground can cause fuse F1 or F2 to blow.
Procedure
1. On the generator panel, set the controller to the OFF mode.
2. Turn off the utility power supply to the transfer switch, using
whatever means provided.
3. Remove fuses F1, F2, and F3 from the fuse holder (see
Figures 39, 40, and 41).
4. Remove the generator control panel cover.
a. On CorePower, disconnect the N1/N2 connector that
supplies the printed circuit board located in the control
panel (see Section 4.1).
b. On PowerPact, disconnect N1 and N2 from the WAGO
block in the customer connection area.
5. Set VOM to measure resistance.
6. Connect the positive meter test lead to Wire N1 at the
terminal block in the control panel.
a. Connect the negative meter lead to the ground lug.
INFINITY should be measured.
b. Connect the negative meter lead to Wire 23 at the
terminal strip. INFINITY should be measured.
c. Connect the negative meter lead to Wire 15B at the terminal
strip. INFINITY should be measured.
d. Connect the negative meter lead to Wire 0 at the terminal
strip. INFINITY should be measured.
e. Connect the negative meter lead to Wire N2 at the terminal
block. INFINITY should be measured.
f. Connect the negative meter lead to the neutral
connection. INFINITY should be measured.
7. Connect the positive meter test lead to Wire N2 at the
terminal block in the control panel.
a. Connect the negative meter lead to the ground lug.
INFINITY should be measured.
b. Connect the negative meter lead to Wire 23 at the terminal
strip. INFINITY should be measured.
c. Connect the negative meter lead to Wire 15B at the terminal
strip. INFINITY should be measured.
d. Connect the negative meter lead to Wire 0 at the
terminal strip. INFINITY should be measured.
e. Connect the negative meter lead to the neutral
connection. INFINITY should be measured.
Results
If a short is indicated in Step 6 or Step 7, repair wiring and re-test.
TEST 35 – CHECK FUSE F3
Discussion
Connected in series with Load Wire T1, F3 provides 120 VAC on
60 Hz units (F3 & F4 provides 220 VAC on 50 Hz) to the generator
controller to operate the battery charger. A blown fuse (or fuses)
may result in a dead battery situation.
PART 3
Procedure
1. On the generator panel, set the controller to the OFF mode.
2. Disconnect Utility from the transfer switch.
3. Remove Fuse F3 from the fuse holder (F3 and F4 on 50 Hz).
4. Inspect and test fuses for an OPEN condition with a Volt-
Ohm-Meter (VOM) set to measure resistance. CONTINUITY
should be measured across the fuse.
Results
1. If fuse(s) is blown (open), replace as needed.
TEST 36 – CHECK T1 WIRING (60 HZ)
Discussion
If fuse F3 is open, a short may have occurred. This test will
determine if either:
• The T1 wiring is shorted to ground or to other circuits.
• The controller is causing the short.
Procedure
1. Set the controller to the OFF mode and remove the 7.5 amp
fuse.
2. Remove F1, F2 and F3 from the fuse holder in the transfer
switch.
3. Disconnect the proper harness connector from the controller
containing Wire T1.
4. Set the Volt-Ohm-Meter (VOM) to measure resistance.
5. Using the chart below, measure and record the resistance
at the customer connection in the generator. (Example:
Connect one meter test lead to Wire T1 and the other meter
test lead to Ground.)
Table 17. Test 36 Results
Ground Wire 194 Wire 23
Wire T1
Results
1. If the VOM indicated INFINITY in any connection points
above, replace the controller.
2. If the VOM indicated CONTINUITY, repair or replace the
wiring in the appropriate circuit.
TEST 36A – CHECK T1 AND T2 WIRING (50 HZ)
Discussion
If fuse F3, F4 or both fuses are open, a short may have occurred.
This test will determine if either:
• The T1 or T2 wiring is shorted to ground or to other circuits.
• T1 and T2 are shorted together.
Section 3.4
Diagnostic Tests
Wire N1 Wire N2
Page 53