Bryant ASPAS1BBA007, Diagnostic Repair Manual, Page: 66 / 144

Page 66
SECTION 3.4
DIAGNOSTIC TESTS
“Utility 1” and “Utility 2” terminals. Normal line-to-line
utility source voltage should be indicated.
Figure 4. Transfer Switch Terminal Block
RESULTS:
1. If voltage reading across the "Utility I" 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
contacts. 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
DANGEROUS VOLTAGES ARE PRESENT AT
TERMINAL LUGS WHEN THE GENERATOR IS
RUNNING. AVOID CONTACT WITH HIGH
VOLTAGE TERMINALS OR DANGEROUS
AND POSSIBLY 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
suitable 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.
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 indicated
in Step 9, but is indicated in Step 10, proceed to Test 31.
PART 3
“V-TYPE” PREPACKAGED
TRANSFER SWITCHES