Motor Load - SPX Cofimco U Style Hub User Manual

Note

Motor Load

The corrected horsepower should be close to but not exceed the
contract horsepower specified by SPX. Determine corrected horse-
power using the following equation.
Actual volts and amperage must be obtained with the fan running
and the specified rate of water flowing over the tower after the motor
and Geareducer have reached operating temperature (approximately
30 minutes of operation).
=
HP
C
HP = Corrected Horsepower
C
VOLTS = Actual Volts
A
AMPS = Actual Amperage
A
DENSITY = Actual Air Density
A
Measurements taken on motors operating with Variable Fre-
quency Drive controls may read up to 15% high from errors in
measuring the approximated sine wave. Instruments capable of
measuring a squared off wave form accurately should be used
for measuring power in this situation.
Do not exceed 30 sec/hour total motor starting time as motor
may overheat.
× AMPS × DENSITY
VOLTS
A A
× AMPS × DENSITY
VOLTS
N N
VOLTS
AMPS
N
HP
N
DENSITY
D
× HP
N
A
= Nameplate Volts
N
= Nameplate Amperage
= Nameplate Horsepower
= Design Air Density
D
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