Unit installation

SCXF-SVX01K-EN 37
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 installer’s responsibility 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 unit’s
control panel.
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:
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
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 unit’s upper left side. 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.
Note: Unit transformers IT1, IT3, 1T4, and IT5 are sized to
provide power to the unit only. Do not use these
transformers to supply power to field equipment.
Field connections to these transformers may create
immediate or premature component failures.
WARNING
Hazardous Service Procedures!
The maintenance and troubleshooting procedures
recommended in this section of the manual could
result in exposure to electrical, mechanical or other
potential safety hazards. Always refer to the safety
warnings provided throughout this section concerning
these procedures. 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. Failure to follow all of the recommended
safety warnings provided, could result in death or
serious injury.
NOTICE:
Use Copper Conductors Only!
Unit terminals are not designed to accept other types
of conductors. Failure to use copper conductors could
result in equipment damage.
NOTICE:
Motor Damage!
Correct phase sequence is critical. If phase sequence of
the incoming line voltage is not correct, it may result in
motor damage.
221 230 227++
3
---------------------------------------------------- 226volts=