N1A N2A
N1
N2
F1
F2
Figure 5. Fuse Holder and Fuses
RESULTS:
1. Replace blown fuse(s) and proceed to Test 34.
2. For Problem 7 (DC Control, Section 4), go to Test 27.
TEST 31 - TEST LIMIT SWITCH XA1
DISCUSSION:
When the transfer switch main contacts are actuated
to their “Utility” position, limit switch XA1 should be
mechanically actuated to its open position. On transfer
to the “Standby” position, the limit switch should actu-
ate to its closed position. If the switch does not actu-
ate to its closed position, retransfer back to “Utility” will
not occur.
PROCEDURE:
1. With the standby generator shut down, set its AUTO-
OFF-MANUAL switch to OFF.
2. Turn off the utility power supply to the transfer switch,
using whatever means provided.
3. To prevent interaction, disconnect Wire 126 and Wire A
from the limit switch terminals.
4. Set a VOM to its “R x 1” scale and zero the meter.
5. Connect the VOM test leads across the two limit switch
terminals from which Wires A and 126 were removed.
6. Manually actuate the main contacts to their “Standby”
position. The VOM should indicate CONTINUITY.
7. Manually actuate the main contacts to their “Utility” posi-
tion. The VOM should read INFINITY.
RESULTS:
Replace limit switch XA1 if it checks bad.
NOTE: Problems with transfer switch opera-
tion can also be caused by (a) defective wiring
between the generator and transfer switch, or (b)
a defective component in the generator circuit
board. See Part 4, “DC Control”.
TEST 32 - CONTINUITY TEST OF WIRING (C1)
DISCUSSION:
This test will ensure that all control wiring has continuity.
1. Set the AUTO-OFF-MANUAL switch to the OFF position.
2. Turn the generator main circuit breaker to the OFF position.
3. Turn off the utility power supply to the transfer switch
using whatever means provided. (Such as utility source
main line circuit breaker).
4. Set your VOM to the “R x 1” scale.
5. Disconnect Wire N2A from the Utility Coil C1 and con-
nect one test lead to it. Connect the other test lead to
Terminal Lug N2 of the transfer switch. CONTINUITY
should be read. Reconnect Wire N2A.
6. Disconnect Wire 126 from transfer relay (TR) and
connect one test lead to it. Connect the other test
lead to limit switch XA1 bottom Terminal Wire 126.
CONTINUITY should be read. Reconnect Wire 126.
7. Disconnect Wire N1A from transfer relay (TR) terminal
and connect one test lead to it. Connect the other test
lead to F1 top fuse Terminal Wire N1A. CONTINUITY
should be read. Reconnect Wire N1A.
RESULTS:
Repair any defective wiring that does not read
CONTINUITY. If wiring tests good, proceed to Test 23.
TEST 33 - CONTINUITY TEST OF WIRING (C2)
DISCUSSION:
This test will ensure that all control wiring has continuity.
1. See Test 32, Step 1
2. See Test 32, Step 2
3. See Test 32, Step 3
4. See Test 32, Step 4
5. Disconnect Wire E2 from the standby coil (C2) and con-
nect one test lead to it. Connect the other test lead to
Terminal Lug E2 of the transfer switch. CONTINUITY
should be read. Reconnect Wire E2.
6. Disconnect Wire 205 from transfer relay (TR) Terminal
6 and connect one test lead to it. Connect the other
test lead to limit switch XB1 top Terminal Wire 205.
CONTINUITY should be read. Reconnect Wire 205.
PART 3
Page 72
“V-TYPE” PREPACKAGED
TRANSFER SWITCHES
SECTION 3.4
DIAGNOSTIC TESTS
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