Guardian 4389 Repair Manual page 71

"V-TYPE" PREPACKAGED
TRANSFER SWITCHES
and connect one test lead to it. Connect the other test
lead to Terminal Lug E1 of the transfer switch. CONTI-
NUITY should be read. Reconnect Wire E1.
RESULTS:
Repair any defective wiring that does not read CON-
TINUITY. If wiring tests good, proceed to Test 23.
TEST 34 - 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 AUTO-OFF-MANUAL
switch to OFF.
2. Turn off the utility power supply to the transfer switch,
using whatever means are provided.
3. Remove fuses F1 and F2 from the fuse holder (see Figure 5).
4. Remove the generator control panel cover. Disconnect
Wire N1 and Wire N2 from the interconnection terminal
in the control panel, or the terminal strip.
5. Set your VOM to the "R x 1" scale. Connect the positive
meter test lead to Wire N1.
a. Connect the negative meter lead to the ground
lug. INFINITY should be measured.
b.Connect the negative meter lead to Wire 23
at ICT or terminal strip. INFINITY should be
measured.
c. Connect the negative meter lead to Wire 194
at ICT or terminal strip. INFINITY should be
measured.
d. Connect the negative meter lead to the neutral
connection. INFINITY should be measured.
6. Set your VOM to the "R x 1" scale. Connect the positive
meter test lead to Wire N2.
a. Connect the negative meter lead to the ground
lug. INFINITY should be measured.
b.Connect the negative meter lead to Wire 23
at ICT or terminal strip. INFINITY should be
measured.
c. Connect the negative meter lead to Wire No.
194 at ICT or terminal strip. INFINITY should be
measured.
d. Connect the negative meter lead to the neutral
connection. INFINITY should be measured.
7. Disconnect Wire N1 and Wire N2 from transformer TX.
8. Connect one test lead to Wire N1 removed in Step 7,
and the other test lead to the ground terminal. INFINI-
TY should be measured.
PART 3
9. Connect one test lead to Wire N2 removed in Step 7,
and the other test lead to the ground terminal. INFINI-
TY should be measured.
10.If no short is indicated in Steps 5 through 9, proceed
with Steps 11 through 15. If a short is indicated in
Steps 5 through 9, repair shorted wiring.
11.Reconnect Wires N1 and N2 to the interconnection ter-
minal or terminal strip.
12.Replace fuses F1 and F2 in the fuse holder.
13.Turn on the utility power supply to the transfer switch
using whatever means is provided.
14.Set VOM to measure AC voltage. Connect one test lead
to Wire N1 and the other test lead to Wire N2. Utility
line to line voltage should be measured.
15.Turn off the utility power supply to the transfer switch
using whatever means is provided.
RESULTS:
If a short is indicated in Steps 5 through 9, repair
wiring and re-test. If utility line to line voltage is mea-
sured in Step 14, proceed to Test 35.
TEST 35 - CHECK TRANSFORMER (TX)
DISCUSSION:
The transformer is a step down type and has two
functions. It supplies approximately 16VAC to the
control board for utility sensing. It also supplies
approximately 16 VAC to the battery charger when
utility is available for trickle charge. A shorted trans-
former can result in fuse F1 or F2 blowing.
PROCEDURE:
1. On the generator panel, set the AUTO-OFF-MANUAL
switch to OFF.
2. Turn off the utility power supply to the transfer switch,
using whatever means is provided.
3. See Figure 6. Disconnect Wires N1, N2, 224, 225,
224A, 225A from transformer (TX).
4. Set a VOM to the "R x 1" scale.
5. Connect one test lead to TX Terminal 1. Connect the
other test lead to TX Terminal 5. Approximately 38.5
ohms should be measured
6. Connect one test lead to TX Terminal 10. Connect the
other test lead to TX Terminal 9. Approximately 1.5
ohms should be measured.
7. Connect one test lead tot TX Terminal 7. Connect the
other test lead to TX Terminal 6. Approximately 0.3
ohms should be measured.
SECTION 3.4
DIAGNOSTIC TESTS
Page 69