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Installation - Electrical
Unit Wiring Diagrams
Specific unit wiring diagrams are provided on the inside of
the control panel door. Use these diagrams for connections
or trouble analysis.
Supply Power Wiring
It is the responsibility of the installer to provide power
supply wiring to the unit terminal block or the non-fused
disconnect switch option. Wiring should conform to NEC
and all applicable code requirements.
Bring supply wiring through the knockout in the lower left
side of the unit control panel. Connect the three phase
wires to the power terminal block or the non-fused
disconnect switch in the control box terminals. Refer to
specific wiring diagrams and fuse information in the control
panel.
WARNING
Hazardous Service Procedures!
Failure to follow all precautions in this manual and on
the tags, stickers, and labels could result in death or
serious injury.
Technicians, in order to protect themselves from
potential electrical, mechanical, and chemical
hazards, MUST follow precautions in this manual and
on the tags, stickers, and labels, as well as the
following instructions: Unless specified otherwise,
disconnect all electrical power including remote
disconnect and discharge all energy storing devices
such as capacitors before servicing. Follow proper
lockout/tagout procedures to ensure the power can
not be inadvertently energized. When necessary to
work with live electrical components, have a qualified
licensed electrician or other individual who has been
trained in handling live electrical components perform
these tasks.
NOTICE
Use Copper Conductors Only!
Failure to use copper conductors could result in
equipment damage as the equipment was not
designed or qualified to accept other types of
conductors.
NOTICE
Motor Damage!
Correct phase sequence is critical. If phase sequence
of the incoming line voltage is not correct, it could
result in motor damage.
PKG-SVX027D-EN
Voltage Range
Voltages must be within ±10% the nameplate voltage.
Ensure the unit voltage is balanced by measuring at the
compressor terminals. Voltage imbalance on three phase
systems can cause motor overheating and premature
failure. Maximum allowable imbalance is 2.0%.
Voltage Imbalance
Read the voltage at the compressor terminals to determine
if it is balanced. Voltage imbalance on three phase systems
can cause motor overheating and premature failure. The
maximum allowable imbalance is 2.0%. Voltage imbalance
is defined as 100 times the sum of the deviation of the
three voltages from the average (without regard to sign)
divided by the average voltage. For example, if the three
measured voltages are 221, 230, and 227, the average
voltage would be:
(221 + 230 + 227) / 3 = 226 volts
The percentage of voltage imbalance is then:
100 * (226 — 221) / 226 = 2.2%
Phase Monitor
Unit is equipped with phase monitor in control box. The
phase monitor will protect against phase loss, imbalance
and reversal of line voltage. If a fault occurs, the red LED
will energize. While the fault condition is present, the phase
monitor interrupts the 115V control circuit. If no faults are
observed, a green LED will be energized.
Control Power
NOTICE
Component Damage!
Failure to follow instructions below could result in
immediate or premature component failures.
Unit transformers are sized to provide power to the
unit only. Do not use these transformers to supply
power to field equipment.
In this example, 2.2% imbalance is not acceptable.
Whenever a voltage imbalance of more than 2.0% exists,
check the voltage at the unit disconnect switch. If the
imbalance at the unit disconnect switch does not exceed
2.0%, faulty unit wiring is causing the imbalance. Conduct a
thorough inspection of the unit electrical wiring connections
to locate the fault, and make any repairs necessary.
Access the connection terminal block through the control
panel on the upper left side of the unit. All wiring should
conform to NEC and applicable local code requirements.
Be sure all wiring connections are secure. Reference the
unit specific diagrams inside the control panel.
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