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).
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| HPC = | VOLTSA × AMPSA × DENSITYD | × HPN | ||
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| VOLTSN × AMPSN × DENSITYA | ||||
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HPC | = | Corrected Horsepower | VOLTSN | = | Nameplate Volts | |
VOLTSA | = | Actual Volts | AMPSN | = | Nameplate Amperage | |
AMPSA | = | Actual Amperage | HPN | = | Nameplate Horsepower | |
DENSITYA | = | Actual Air Density | DENSITYD | = | Design Air Density | |
Measurements taken on motors operating with Variable Fre-
Notequency 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.
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