Electrical Phasing - Trane IntelliPak CG-SVX02B-EN Installation & Operation Manual

At low operating voltage and high operating load, the imbal-
ance may be around 4 percent. At high operating voltage
and low operating load, the imbalance may be as high as
15 percent.
If an imbalance situation is suspected within the compres-
sor (current draw unequal between phases) and the line
voltage imbalance does not exceed 2 percent;
1. Turn the field supplied disconnect switch, located up-
stream of the unit to the "Off" position.
WARNING
Hazardous Voltage!
Disconnect all electric power, including remote discon-
nects before servicing. Follow proper lockout/tagout
procedures to ensure the power can not be inadvert-
ently energized. Failure to disconnect power before ser-
vicing could result in death or serious injury.
2. Disconnect the compressor leads at the compressor ter-
minals.
3. Measure the resistance of the compressor windings at
the compressor terminals.
The actual resistance measured across each winding is
not as important as the amount of variation between the
windings. The actual resistance measured may vary due
to the accuracy of the meter, rounding off of the resis-
tance readings, and the amount of resistance between
the meter leads and the compressor terminals.
Since the amount of copper in each winding is very con-
sistent, the variance between the windings should not
exceed 7 percent.
Example: Typical 10 Ton, 460 volt, 60 Hz compressor has a
winding resistance of 1.44 to 1.09 Ohms.

Electrical Phasing

Unlike traditional reciprocating compressors, scroll com-
pressors are phase sensitive. Proper phasing of the electri-
cal supply to the unit is critical for proper operation and reli-
ability.
System Pre-Start Procedures
The compressor motor is internally connected for clockwise
rotation with the incoming power supply phased as
A, B, C.
Proper electrical supply phasing can be quickly determined
and corrected before starting the unit by using an instru-
ment such as an Associated Research Model 45 Phase Se-
quence Indicator and following the steps below:
WARNING
Hazardous Voltage!
Disconnect all electric power, including remote discon-
nects before servicing. Follow proper lockout/tagout
procedures to ensure the power can not be inadvert-
ently energized. Failure to disconnect power before ser-
vicing could result in death or serious injury.
HIGH VOLTAGE IS PRESENT AT TERMINAL BLOCK
1TB1 OR UNIT DISCONNECT SWITCH 1S14.
[ ] Turn the field supplied disconnect switch that provides
power to terminal block 1TB1 or to the unit mounted dis-
connect switch 1S14 to the "Off" position.
[ ] Connect the phase sequence indicator leads to terminal
block 1TB1 or to the unit mounted disconnect switch
1S14 as follows;
Black (phase A)
Red (phase B)
Yellow (phase C)
[ ] Close the disconnect switch or circuit protector switch
that provides the supply power to the unit's terminal
block 1TB1 or the unit mounted disconnect switch 1S14.
[ ] Observe the ABC and CBA phase indicator lights on the
face of the sequencer. The ABC indicator light will glow if
the phase is ABC. If the CBA indicator light glows, open
the disconnect switch or circuit protection switch and re-
verse any two power wires.
[ ] Restore the main electrical power and recheck the phas-
ing. If the phasing is correct, open the disconnect switch
or circuit protection switch and remove the phase se-
quence indicator.
40
to L1
to L2
to L3