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AE-1318 R1
© 2008 Emerson Climate Technologies
Printed in the U.S.A.
Application Engineering
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used to sense motor temperatures and the fi fth is used
as a discharge temperature sensor. For the INT69SU,
there are four PTC (positive temperature coeffi cient)
internal thermisters connected in series. All four are
used to sense motor temperature. The thermister
circuit is connected to the protector module terminals
S1 and S2.
When any thermister reaches a limiting value, the
module interrupts the control circuit and shuts off the
compressor. After the thermister has cooled suffi ciently,
the resistance will decrease, thus allowing the module
to reset. However, the module has a 30-minute time
delay before reset after a thermister trip.
For all other compressors, conventional internal line
break motor protection is provided.
Programmable Logic Controller Requirements
If the INT69SCY (071-0620-00) or INT69SU (071-
0641-00) module is applied in conjunction with a
Programmable Logic Controller, it is important that a
minimum load is carried through the M1-M2 control
circuit contacts.
The minimum required current through the module
relay contacts needs to be greater than 100 milliamps
but not to exceed 5 amps. If this minimum current is
not maintained, this has a detrimental effect upon the
long-term contact resistance of the relay and may
result in false compressor trips.
PLC operated control circuits may not always provide
this minimum current. In these cases modifi cations
to the PLC control circuit are required. Consult your
application engineering department for details.
Phase Protection
The INT69SCY module provides phase protection
for the compressor. The module senses the correct
phase sequence, phase loss and voltage sag for each
leg (L1, L2 and L3) of the incoming power supplied to
the compressor. At installation the three phases of the
power supply must be wired in the correct 120° phase
sequence. This will ensure the compressor will start
and operate in the correct clockwise direction.
The INT69SCY module trips (M1-M2 contacts open)
when the module senses a phase loss. There is a 5
minute time delay before the module attempts a restart.
If all three phases are present, then the module will
reset (M1-M2 contacts will close) and the compressor
will start and run. If not, the module will attempt a
restart after another 5 minute time delay. After 10
failed attempts to restart, the module will lock-out (M1-
M2 contacts will remain open) and can only be reset
by removing the power from T1-T2 for a minimum of
5 seconds.
The INT69SCY is intended to protect the compressor.
The L1/L2/L3 and S1/S2 leads are pre-wired on the
compressor and are engineered to work in conjunction
with the motor protector module. The module
Figure 3
Scroll Wiring Schematic
