Operator’s Manual Testing & Service
10 381333-194 B
Testing & Service
TROUBLE-SHOOTING
Note any optional accessories that may be furnished on the
7ACTB and review their operation. Refer to any separate
drawings and/or instructions that may be packed with the
7ACTB. See Table B.
Hazardous voltage capable of causing shock, burns,
or death is used in this switch. Do not touch the
power or load terminals of the bypass switch or
transfer switch!
Table B. Trouble-Shooting Checks.
PROBLEM
CHECK IN NUMERICAL SEQUENCE
1 OPERATION 2 GEN-SET 3 VOLTAGE
Engine–generator set does
not start when the Transfer
Control switch is turned
and held in Transfer Test
position or when normal
source fails.
Hold Transfer Test switch 15
seconds or the outage must be
long enough to allow for Feature
1C time delay plus engine
cranking and starting time.
Starting control must be in the
automatic position. Batteries
must be charged and
connected. Check wiring to
engine starting contacts.
-
Transfer switch does not
transfer the load to the
emergency source after the
engine–generator set starts.
Wait for Feature 2B time delay to
time out (if used)
Generator output circuit breaker
must be closed. Generator
frequency must be at least 95%
of nominal (57 Hz for a 60 Hz
system.) *
Voltmeter should read at least
90% of nominal phase to
phase voltage between
transfer switch terminals EA
and EC (or EL1 and EL2 for 2
pole switches). *
Transfer switch does not
transfer the load to normal
source when normal returns
or when the Transfer
Control switch is released.
Wait for Feature 3A time delay to
time out (if used)
-
Voltmeter should read at least
90% of nominal phase to
phase voltage between
transfer switch terminals NB
and NC, NC and NA, and NA
and NB (or NL1 and NL2 for 2
pole switches).
Engine–generator-set does
not stop after load retransfer
to the normal source.
Wait for Feature 2E time delay to
time out (if used)
Starting control must be in the
automatic position. -
Failure to Synchronize
light comes on.
Conditions of Normal or Emergency Sources not suitable for closed transition transfer.
Recheck voltage and frequency of both sources. Press Alarm Reset pushbutton.
Extended Parallel Time
light comes on.
CN and CE contacts are closed longer than setting in the Controller. Open the disconnected source
circuit breaker, then call your nearest ASCO Service Center for assistance.
TS Locked Out
light comes on.
Transfer lockout operation has occurred; transfer switch is disabled from automatic operation. Open
the disconnected source circuit breaker, then call your nearest ASCO Power Services, Inc. for
assistance
These are factory settings. Refer to the Controller User’s Guide.
If the problem is isolated to circuits on the controller or the transfer switch, call your local ASCO Power Technologies
sales office or ASCO Power Services, Inc.: in the United States or Canada, call 1–800–800–2726. Furnish the Serial No.,
Catalog No., and Bill of Material (BOM) No. from the transfer switch nameplate.
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