CGWF-SVX01A-EN 47
Installation Electrical
Scroll Compressor Electrical Phasing
It is important that proper rotation of the scroll compressor be established before the
machine is started. Proper motor rotation requires confirmation of the electrical phase
sequence of the power supply. The motor is internally connected for clockwise
rotation with the inlet power supply phased A,B,C.
To confirm the correct phase sequence (ABC), use a Model 45 Associated Research
Phase indicator or equivalent.
Basically, voltages generated in each phase of a polyphase alternator or circuit are
called phase voltages. In a three-phase circuit, three sine wave voltages are
generated, differing in phase by 120 electrical degrees. The order in which the three
voltages of a three-phase system succeed one another is called phase sequence or
phase rotation. This is determined by the direction of rotation of the alternator. When
rotation is clockwise, phase sequence is usually called “ABC”, when
counterclockwise, “CBA”.
This direction may be reversed outside the alternator by interchanging any two of the
line wires. It is this possible interchange of wiring that makes a phase sequence
indicator necessary if the operator is to quickly determine the phase rotation of the
motor.
Correcting Improper Electrical Phase Sequence
Proper compressor motor electrical phasing can be quickly determined and corrected
before starting the unit. Use a quality instrument such as an Associated Research
Model 45 Phase Sequence Indicator and follow this procedure.
WARNING
Hazardous Voltage!
During installation, testing, servicing and troubleshooting of this
product, it may be necessary to work with live electrical components.
Have a qualified licensed electrician or other individual who has been
properly trained in handling live electrical components perform these
tasks. Failure to follow all electrical safety precautions when exposed to
live electrical components could result in death or serious injury.
1. Turn Chiller off.
2. Open the electrical disconnect or circuit protection switch that provides line
power to the line power terminal block (1TB1) in the control panel (or to the unit-
mounted disconnect 1S1).
3. Connect the phase sequence indicator leads to 1TB1 (or 1S1) as follows:
4. Turn power on by closing the unit supply power fused disconnect switch.
5. Read the phase sequence displayed on the indicator. The “ABC” LED on the face
of the phase indicator will glow if phase sequence is ABC.
6. If the “CBA” indicator glows instead, open the unit main power disconnect and
switch two line leads on 1TB1 (1S1). Reclose the main power disconnect and
recheck phasing.
7. Reopen the unit disconnect and disconnect the phase indicator.
Phase Seq. Lead 1TB1 Terminal
Black (Phase A) 1
Red (Phase B) 2
Yellow (Phase C) 3
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