© 2000 Copeland Corporation
Printed in U.S.A.
10-1313
1
Copeland 10-1313
Application Engineering Bulletin
AE-1313
Issued September, 2000
GUIDELINES TO USING A THREE PHASE VOLTAGE MONITOR
10-1313
INTRODUCTION
A phase monitor can be used with any three phase
motor. A monitor such as the Copeland 085-0160-00 is
recommended for monitoring remote locations or envi-
ronments with a history of adverse voltage fluctuations.
Many compressor failures are caused by an intoler-
able line voltage. These voltage variations can have
many different sources such as contactor failure or
ground interference. Irrelevant of the cause, compres-
sor failures due to voltage fluctuations may be pre-
vented. Although the voltage fluctuations themselves
may be inevitable, actual motor damage can usually be
averted.
FAULT DETECTION
The phase monitor checks for critical faults
•Phase loss
•Phase reversal
•High voltage
•Low voltage
•Voltage unbalance
A phase reversal is very damaging to phase sensi-
tive machines such as scroll compressors, screw com-
pressors, and fan motors. A phase loss will cause
excessively high current resulting in high temperatures
in the other two motor phases. High voltage causes
excessive temps inside the motor. Low voltage in-
creases the slip of the motor producing excess heat.
Phase unbalance is when the voltage to each phase is
not equal, as a result, some windings do more work than
others. This causes excessive heat.
ELECTRICAL WIRING SET UP
For single contactor systems, connect the monitor
to the three phase power supply as shown in Figure 1 .
For a part winding start with two contactors and two
phase monitors, connect the monitors as shown in
Figure 2.
Figure 1
Voltage Wiring for Three Phase Line Monitors
*
*
*1 amp fuse recommended
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