CLCH-SVX06A-EN •
T-Series Climate Changer Air Handler IOM
77
Start-Up
Calculate Motor Voltage Imbalance
After startup, measure the motor voltage and amperage on all phases to ensure proper
operation. The readings should fall within the range given on the motor nameplate. The
maximum allowable voltage imbalance is 2 percent.
Voltage imbalance is defined as 100 times the sum of the deviation of the three voltages
from the average, divided by twice the average voltage. For example, if the three
measured voltages are 221, 230 and 227, the average voltage would be 226 volts. The
percent of voltage imbalance is then calculated.
Voltage imbalance =
where:
A = (226-221) + (230-226) + (227-226)
Voltage imbalance = 2.2% (not acceptable)
In the example, 2.2 percent imbalance is not acceptable and the power company should
be notified to correct it.
Tension the Fan Belt
CAUTION
Belt Tension!
Do not over-tension belts. Excessive belt tension will reduce fan and motor bearing
life, accelerate belt wear and possibly cause shaft failure. Under tensioning belts is the
primary cause of premature belt failure. Belts should not squeal at startup. Recheck
belt tension after 8, 24, and 100 hours of operation and monthly thereafter.
Check the fan belt tension at least three times during the first days of operation because
there is a rapid decrease in tension until the belt settles in. To measure belt tension, use
a belt tensiometer (see
Figure 58
and
Figure 59
). Determine actual deflection by
depressing one belt with the belt tensiometer and measuring the deflection relative to the
other belts or to belt line. Adjust the belt tension to the correct pounds force and tighten
all set screws to the proper torque.
100A
2
AvgVoltage
×
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