Guardian 4389 Repair Manual page 69

"V-TYPE" PREPACKAGED
TRANSFER SWITCHES
RESULTS:
1. If voltage reading across the UTILITY 1 and UTILITY 2
terminals is zero, go to Test 30.
2. If voltage reading is good, go to Test 29.
3. For Problem 14 ONLY; if voltage is good, repair N1/N2
open wiring between Transfer Switch and Generator.
TEST 29- CHECK VOLTAGE AT UTILITY
CLOSING COIL C1
DISCUSSION:
Utility source voltage is required to energize utility
closing coil C1 and effect retransfer back to the
"Utility" source. This voltage is delivered to the utility
closing coil via Wires N1A and N2A, the transfer
relay's normally-closed contacts (relay de-energized),
Wire 126, Limit Switch XA1, and a bridge rectifier.
PROCEDURE:
1. On the generator control panel, set the AUTO-OFF-
MANUAL switch to OFF.
2. Turn off the utility power supply to the transfer switch,
using whatever means provided (such as a utility source
main line circuit breaker).
3. Set the generator main line circuit breaker to its OFF or
"Open" position.
4. Check the position of the transfer mechanism main con-
tacts. The moveable load contacts must be connected
to the stationary utility contacts. If necessary, manually
actuate the main contacts to their "Utility" source side
(load connected to the "Utility" source).
DANGER: BE CAREFUL! HIGH AND DANGER-
!
OUS VOLTAGES ARE PRESENT AT TERMI-
NAL LUGS WHEN THE GENERATOR IS RUN-
NING. AVOID CONTACT WITH HIGH VOLT-
AGE TERMINALS OR DANGEROUS AND POS-
SIBLY LETHAL ELECTRICAL SHOCK MAY
RESULT. DO NOT PERFORM THIS VOLTAGE
TEST WHILE STANDING ON WET OR DAMP
GROUND, WHILE BAREFOOT, OR WHILE
HANDS OR FEET ARE WET.
5. Disconnect Wire N2A from the utility closing coil (C1).
Connect one meter test Lead to Wire N2A. Use a suit-
able and safe connection to this wire, such as an alligator
clip that attaches to the meter test probe. Isolate this wire
and test probe from any other potential source or ground.
6. Set the generator main line circuit breaker to its "On" or
"Closed" position.
7. Set the generator AUTO-OFF-MANUAL switch to AUTO.
a. The generator should crank and start.
PART 3
b. About 15 seconds after engine startup, the
transfer relay should energize and transfer to
the "Standby" source should occur.
8. When you are certain that transfer to "Standby" has
occurred, turn ON the utility power supply to the transfer
switch. After a 15 seconds, retransfer back to the
"Utility" source should occur.
9. Locate on the utility closing coil the terminal that Wire A
is connected to (see Figure 1, Section 3.4). Connect the
other meter test lead to this terminal. Generator line to
line voltage should be indicated. If generator voltage
is NOT indicated, proceed to Step 10.
10.With Wire N2A still connected to one test probe, connect
the other meter test lead to Wire 126 on Limit Switch
XA1 (see Figure 1, Section 3.4). Generator line to line
voltage should be measured.
RESULTS:
1. In Step 7, if the generator does NOT crank or start, refer
to Part 4, "DC Control".
2. In Step 7, if transfer to the "Standby" source does NOT
occur, go to Problem 1.
3. In Step 9, if normal utility source line-to-line voltage is
indicated but retransfer back to "Utility" does NOT occur,
go to Test 24.
4. If normal utility source line-to-line voltage is NOT indi-
cated in Step 9, but is indicated in Step 10, proceed to
Test 31.
5. If normal utility source line-to-line voltage is NOT indicat-
ed in Step 8, and is NOT indicated in Step 9, proceed to
Test 32.
TEST 30 - CHECK FUSES F1 AND F2
DISCUSSION:
Fuses F1 and F2 are connected in series with the
UTILITY 1 and UTILITY 2 circuits, respectively. A
blown fuse will open the applicable circuit and will
result in (a) generator startup and transfer to
"Standby", or (b) failure to retransfer back to the utility
source.
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 provided.
3. Remove fuses F1 and F2 from the fuse holder (see
Figure 5).
4. Inspect and test fuses for blown condition.
SECTION 3.4
DIAGNOSTIC TESTS
Page 67