Voltage Imbalance; Rt-Svx23F-En - Trane WSC036E Installation, Operation And Maintenance Manual

Table 7. Temperature versus resistance (temperature
vs. resistance is negative)
Temperature
Degrees F° Degrees C°
-20° -28.9°
-15° -26.1°
-10° -23.3°
-5° -20.6°
0° -17.8°
5° -15.0°
10° -12.2°
15° -9.4°
20° -6.7°
25° -3.8°
30° -1.1°
35° 1.7°
40° 4.4°
45° 7.2°
50° 10.0°
55° 12.8°
60° 15.6°
65° 18.3°
70° 21.1°
75° 23.9°
80° 26.7°
85° 29.4°
90° 32.2°
95° 35.0°
100° 37.8°
Use the checklist provided below in conjunction with the
"General Unit Requirements" checklist to ensure that the
unit is properly installed and ready for operation.
WARNING
Hazardous Voltage!
Disconnect all electric power, including remote
disconnects before servicing. Follow proper lockout/
tagout procedures to ensure the power can not be
inadvertently energized. Failure to disconnect power
before servicing could result in death or serious injury.
• Check all electrical connections for tightness and
"point of termination" accuracy.
• Verify that the condenser airflow will be unobstructed.
• Verify that the condenser fan and indoor blower turn
freely without rubbing and are properly tightened on
the shafts.
• Check the supply fan belts for proper tension and the
fan bearings for sufficient lubrication. If the belts
require adjustment, or if the bearings need lubricating,

RT-SVX23F-EN

Nominal Resistance
170.1 K - Ohms
143.5 K - Ohms
121.4 K - Ohms
103.0 K - Ohms
87.56 K - Ohms
74.65 K - Ohms
63.80 K - Ohms
54.66 K - Ohms
46.94 K - Ohms
40.40 K - Ohms
34.85 K - Ohms
30.18 K - Ohms
26.22 K - Ohms
22.85 K - Ohms
19.96 K - Ohms
17.47 K - Ohms
15.33 K - Ohms
13.49 K - Ohms
11.89 K - Ohms
10.50 K - Ohms
9.297 K - Ohms
8.247 K - Ohms
7.330 K - Ohms
6.528 K - Ohms
5.824 K - Ohms
refer to the maintenance section of this manual for
instructions.
• Verify that a condensate trap is installed and the piping
is properly sized and pitched.
• Verify that the correct size and number of filters are in
place.
• Inspect the interior of the unit for tools and debris and
install all panels in preparation for starting the unit.

Voltage Imbalance

Three phase 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.
Excessive three phase voltage imbalance between phases
will cause motors to overheat and eventually fail.The
maximum allowable voltage imbalance is 2%. Measure
and record the voltage between phases 1, 2, and 3 and
calculate the amount of imbalance as follows:
100 X AV - VD
% Voltage Imbalance =
Volt 1 + Volt 2 + Volt 3
AV (Average Voltage) =
V1, V2, V3 = Line Voltage Readings
VD = Line Voltage reading that deviates the farthest from
the average voltage.
Example: If the voltage readings of the supply power
measured 221, 230, and 227, the average volts would be:
221 + 230 + 227
= 226 Avg.
3
VD (reading farthest from average) = 221
The percentage of Imbalance equals:
100 X 226 - 221
= 2.2%
226
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.
Pre-Start
where;
AV
3
35