Screw Compressor Central Chiller
Chapter 3: Installation
16
3-3 Making Electrical Connections
Screw Compressor Central Chilling systems are designed for three-phase voltage operation.
Refer to the unit nameplate for proper voltage and amperage requirements.
Note:
Make sure you provide a correctly sized and protected supply of electrical
power to the unit.
Refer to National Electric Code (NEC) Article 430-24 through 430-26 for
proper feeder conductor and supply disconnect sizing.
Maintain a safe ground and disconnect the power supply before servicing
the unit. A qualified electrician should make electrical connections, and
disconnect and lock out electricity using OSHA 29 CFR 1910.147
standards when you need to service the unit.
Check serial tag voltage and amperage requirements and make sure your electrical service
conforms
before
making any electrical connections. Total running amps for the Screw
Compressor Central Chilling systems are listed on the nameplate. Customer connections can
be run to the supply terminals from either side of the unit.
WARNING!
Make sure that all three phases are wired correctly. If not wired properly, the compressor
will run
backwards
and cause severe damage to the compressor. Again, check the unit
nameplate for correct voltage and amperage. Compressors must be wired in sequence
(ABC). If not wired properly, the unit can be damaged if run backwards.
DANGER!
Improper electrical connections can damage the unit and cause serious operator injury
or death! Compressor damage will occur if compressors are run backwards.
Bring properly sized power leads and ground from a fused disconnect (installed by your
electrician) to the unit. Provide external overcurrent protection to the unit, using circuit
breakers or fuses. If you use fuses, make sure that they are dual-element time-delay fuses,
sized according to your electrical code. Make sure that
all
electrical connections are
tight
.
Note:
The following MUST be followed when making electrical connections for
your central chiller:
1.
Electrical connections must comply with all applicable electrical
codes.
2.
The chiller must be grounded in accordance with NEC Article
250.
3.
Voltage must be within plus or minus ten percent (
r
10%) of the
nameplate rating with 2% maximum imbalance between legs.
4.
Make sure your installer provides external protection.
Caution!
Check Compressor Rotation Before Starting Unit!
Connect a phase monitor and phase incoming power ABC.
Check the electrical wiring schematic
provided in your Customer Information packet
for additional information.
