OPTIONAL ACCESSORIES
(continued)
OPTIONAL ACCESSORY
27
MOTOR LOAD TRANSFER
y-
O Acc. 27,
if
furnished, is an inphase monitor control for
transfer and retransfer of motor loads, so that inrush cur
rents do not exceed nonnal starting currents. This avoids
nuisance tripping of circuit breakers and possible mechan
ical damage to motor couplings. Accessory 27 is built-in to
the control panel and is activated at the factory when or
dered by the customer. DIP switch S4 (actuator 6) acti
vates this accessory. Up
=
ON, down
=
OFF.
Acce�"ory
S4
Sw I t ch
27
DIP
Actua T or
Se t t Ing
Sw I t c h
(,
n o t ue.d
off
act l va t .d
on
Sequence of Operation
Normal Source Restoration:
SE relay energizes and ER
relay
is
dropped out. After approximately
2
seconds the
inphase monitor senses both sources of power, and its out
put relay energizes to initiate inphase transfer. The TS
coil is energized and the standard Sequence of Operation
is resumed.
When
Transfer Test
switch is used, the inphase monitor
senses both sources of power approximately 2 seconds af-
5-5
ter the
ER
relay energizes. The TS coil is energized and
the standard Sequence of Operation is resumed.
If
either source of power is not available when the inphase
monitor starts its sensing mode, the output relay picks up
after
2
seconds and allows the TS coil to be energized.
Trouble-Shooting
1. Connect a voltmeter between terminals NA and EA
on the transfer switch. Set the meter scale to at least
twice the system phase to phase voltage.
2. Manually start the engine generator plant. After it
has reached maximum output voltage, the meter
needle should sweep back and forth at a regular rate
between 0 volts and about twice the system voltage.
3. Depress and hold the
Transfer Test
switch. The load
should transfer to the emergency source when the
meter needle is near 0 volts.
If
transfer does not oc
cur, Acc. 27 is malfunctioning.
4 Release the
Transfer Test
switch. The load should re
transfer back to the nonnal source after Feature 3A
time delay, if used. The retransfer should occur when
the needle is near 0 volts.
If
retransfer does not occur
after the time delay, Acc.
27
is malfunctioning.
5. Immediate retransfer may be accomplished by manu
ally shutting down the engine. Make sure that full
rated nonnal voltage is available before doing this.
6. Disconnect and remove the voltmeter.
www
. ElectricalPartManuals
. com