Unit Voltage Power Supply; Unit Voltage Imbalance - Trane RTAA-130 Installation, Operation And Maintenance Manual

RTAA-IOM-3
[ ] Energize the evaporator and
Domestic Water Heater heat tape.
[ ] Fill the evaporator chilled water
circuit. Refer to Table 1 for
evaporator liquid capacities. Vent
the system while it is being filled.
Open the vent on the top of the
evaporator during filling and close
when filling is completed.
Customer Note
The use of improperly treated or
untreated water in this equipment may
result in scaling, erosion, corrosion,
algae or slime. The services of a
qualified water treatment specialist
should be engaged to determine what
treatment, if any, is advisable. The
Trane Company warranty specifically
excludes liability for corrosion, erosion
or deterioration of Trane equipment.
Trane assumes no responsibilities for
the results of the use of untreated or
improperly treated water, or saline or
brackish water.
Caution: Do not used untreated or
improperly treated water.
Equipment damage may occur.
Caution: Do not fill the water
systems unless the evaporator and
Domestic Water Heater heat tapes
have been energized.
[ ] Close the fused-disconnect
switch(es) that supplies power to
the chilled water pump starter.
[ ] Start the chilled water pump to
begin circulation of the chilled water.
Inspect all piping for leakage and
make any necessary repairs.
[ ] With chilled water circulating
through the system, adjust water
flow and check water pressure drop
through the evaporator. Refer to
Figure 23.
[ ] Adjust the chilled water flow switch
(if installed) for proper operation.
[ ] Prove Chilled Water Pump Interlock
and External Auto/Stop as described
in Interconnecting Wiring: Chilled
Water Pump Interlock and External
Auto/Stop.
Caution: Chilled Water Pump
Interlock and External Auto/Stop
information must be adhered to or
equipment damage may occur.
[ ] Check and set, as required, all UCM
Menu items.
[ ] Stop the chilled water pump.
122
Unit Voltage
Power Supply
Voltage to the unit must meet the
criteria given in Table 10. Measure each
leg of the supply voltage at the unit
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.
Caution: Inadequate voltage to the
unit can cause control components
to malfunction and shorten the life
of relay contact, compressor
motors and contactors.

Unit Voltage Imbalance

Excessive voltage imbalance between
the phases of a three-phase system can
cause Motors to overheat and
eventually fail. The maximum
allowable imbalance is 2 percent.
Voltage imbalance is determined using
the following calculations:
(V x - V ave ) x 100
% Imbalance =
V ave
/ 3
V ave = (V 1 + V 2 + V 3 )
V x = phase with greatest difference
from V ave (without regard to sign)
For example, if the three measured
voltages are 221, 230, and 227 volts, the
average would be:
221 +230 +227 = 226
3
The percentage of imbalance is then:
100 (221 - 226) = 2.2%
226
This exceeds the maximum allowable
(2%) by 0.2 percent.