Unit Voltage Power Supply; Unit Voltage Imbalance; Unit Voltage Phasing - Trane R Series Installation, Operation And Maintenance Manual

Pre-Start Checkout
NOTICE:
Water Born Debris!
To prevent evaporator or condenser damage, pipe
strainers must be installed in the water supplies to
protect components from water born debris. Trane is
not responsible for equipment-only-damage caused by
water born debris.
6. Close the fused-disconnect switch(es) that supplies
power to the chilled water pump starter.
7. Start the chilled water pump to begin circulation of the
water. Inspect all piping for leakage and make any
necessary repairs.
8. With water circulating through the system, adjust
water flow and check water pressure drop through the
evaporator.
9. Adjust the chilled water flow switch for proper
operation.
10. Check for adequate oil level in oil separator or oil sump.
Note: If no oil is found in the sump, contact Pueblo
Technical Service before starting compressor.
11. Reapply power to complete procedures.
12. Prove all Interlock and InterconnectingWiring Interlock
and External as described in the Electrical Installation
section.
13. Check and set, as required, all CH530 menu items.
14. Stop the chilled water pump.
15. Energize compressor and oil separator heaters 24
hours prior to unit start-up.

Unit Voltage Power Supply

NOTICE:
Equipment Damage!
Provide adequate voltage to the unit. Failure to do so
could result in control components malfunction, and
shorten the life of relay contact, compressor motors
and contactors.
Voltage to the unit must meet the criteria given in the
Installation-Electrical Section. Measure each leg of the
supply voltage at the unit's main power fused- disconnect.
If the measured voltage on any leg is not within specified
range, notify the supplier of the power and correct the
situation before operating the unit.

Unit Voltage Imbalance

Excessive voltage imbalance between the phases of three-
phase system can cause motors to overheat and
eventually fail.The maximum allowable imbalance is 2%.
Voltage imbalance is determined using the following
calculations:
128
% Imbalance = [(V - V
x
V = (V1 + V2 + V3)/3
ave
V = phase with the greatest difference from V
x
(without regard to the sign)
For example, if the three measured voltages are 221, 230,
and 227 volts, the average would be:
(221+230+227)/3 = 226
The percentage of the imbalance is then:
[100(221-226)]/226 = 2.2%
This exceeds the maximum allowable (2%) by 0.2 percent.

Unit Voltage Phasing

NOTICE:
Equipment Damage!
It is imperative that L1, L2, L3 in the starter be
connected in the A-B-C phase sequence to prevent
equipment damage due to reverse rotation.
Proper rotation of the compressors must be established
before the unit 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 incoming power supply phased A, B, C.
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. It
is determined by the direction of rotation of the alternator.
For clockwise rotation, phase sequence is called "ABC,";
for 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.
Proper compressor motor electrical phasing can be quickly
determined and corrected before starting the unit. Use a
quality instrument, such as the Associated Research
Model 45 Phase Sequence Indicator, and follow this
procedure.
) x 100]/V
ave ave
ave
RTAC-SVX01J-EN