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1CR
Supplies power to the compressor contactor
coil/relay. The output can supply 12 amps at 125
volts and 7 amps at 250 volts. The module uses
this output to turn on and off the compressor
when required. Whenever power is supplied to
L1, 1CR is closed, pulling in the contactor and
starting the compressor. The 1CR LED will light
whenever the 1CR output is closed.
2CR
Supplies power to the compressor part-wind
contactor coil/relay if part-wind start is used. The
output can supply 12 amps at 125 volts and 7
amps at 250 volts. This output is automatically
energized 1.25 seconds after 1CR during start-
up. The 2CR LED will light whenever the 2CR
output is closed. If part-wind start is not used,
connect the economizer line solenoid to this
output.
UNL
Each 05T and 06T screw compressor is supplied
with 1 step of unloading. The unloader coil and Vi
coil (if using an 05TR or 06TR compressor) are
connected in parallel to this output. If the
application calls for taking advantage of
unloading the compressor, or operating at the low
Vi setting, a rack controller or other controlling
device must be used. Connect the signal from the
rack controller or other controlling device in series
between the CEM output and the unloader or Vi
coil. The CEM has a built-in 45-second time delay
between when 1CR is closed and the UNL output
is closed. This allows the compressor to run for
45 seconds unloaded and with a low Vi on start-
up which assists in creating a softer start. The
UNL LED will light when the output is closed.
ALM
Whenever a shutdown or fault condition occurs,
power is supplied to this output and its
corresponding LED lighted. The intention of this
output is to allow a signal to be sent back to the
rack controller or other signaling device,
informing a person of the failure.
LIQ
Supplies power to the motor cooling valve coil.
Whenever the motor or discharge temperatures
exceed their limits, this output is closed to inject
liquid into the motor compartment. During this
time the liquid LED is energized along with the
corresponding motor or discharge LED. When the
motor or discharge has cooled to an acceptable
level, the output is opened.
OIL
The oil line and the economizer line solenoids are
connected in parallel at this output. If no part-
wind start is used, connect the economizer line
solenoid to the 2CR output. It is critical that oil be
supplied to the compressor whenever it is running
and not supplied when off. This output ensures
that will happen. There is a 2-second time delay
between when 1CR is closed and OIL is closed
TIME DELAY
The CEM also has a built-in timer which will delay
the start of the compressor anywhere between 0
and 300 seconds from when power is supplied to
L1. This is useful with multiple compressors on a
rack to prevent all compressors from starting at
the same time.
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