Trane IntelliPak RA 20, Installation, Operation And Maintenance Manual

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30 RT-SVX063E-EN
control box, and the other end routed to a suitable
sensing location within the controlled space.
Voltage Supply
Electrical power to the unit must meet stringent
requirements for the unit to operate properly. Measure
each leg (phase-to-phase) of the power supply. Each
reading must fall within the utilization range stamped
on the unit nameplate. If any of the readings do not fall
within the proper tolerances, notify the power
company to correct this situation before operating the
unit.
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Voltage Imbalance
Excessive three phase voltage imbalance between
phases will cause motors to overheat and eventually
fail. The maximum allowable voltage imbalance is 2
percent. Measure and record the voltage between
phases 1, 2, and 3 and calculate the amount of
imbalance as follows:
percent Voltage Imbalance =
where;
AV (Average Voltage) =
V1, V2, V3 = Line Voltage Readings
VD = Line Voltage reading that deviates the farthest
from the average voltage.
E Ex xa am mp plle e:: If the voltage readings of the supply power
measured 221, 230, and 227, the average volts would
be:
VD (reading farthest from average) = 221
The percentage of Imbalance equals:
The 2.2% imbalance in this example exceeds the
maximum allowable imbalance of 2.0%. This much
imbalance between phases can equal as much as a
20% current imbalance with a resulting increase in
motor winding temperatures that will decrease motor
life. If the voltage imbalance is over 2%, notify the
proper agencies to correct the voltage problem before
operating this equipment.
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