Motor Load
1.The corrected horsepower should be close to but not exceed the contract horsepower specified (see page 2). Determine corrected horsepower with this equation:
|
| HP |
| = VOLTSA ⋅ AMPSA ⋅ DENSITYD | ⋅ HPN | |||
|
|
| C |
| VOLTSN ⋅ AMPSN ⋅ DENSITYA |
| ||
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 | |||
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 opera- tion).
2.The blade pitch can be changed to obtain contract horsepower. A one degree pitch change will change the power about eight horsepower. If blades are repitched, follow pitching and fastener tightening instructions detailed in the Fan Assembly section of this manual.
Measurements taken on motors operating with Variable Frequency 
CautionDrive 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.
When checking and/or changing blade pitch or cycling fan in normal operation, do not exceed 30 sec/hour total motor starting time as mo- tor may be overheated.
Service
When contacting your Marley sales representative for repair or replacement parts, please refer to the tower serial number.
Replacement blades can be installed without rebalancing. The fan series—
If rebalancing is required, return the fan hub to Marley for factory rebal- ance. Obtain a Customer Return Material tag from your Marley sales representative.
7401 WEST 129 STREET OVERLAND PARK, KANSAS 66213 UNITED STATES 913 664 7400 spxcooling@ct.spx.com spxcooling.com
In the interest of technological progress, all products are subject to design and/or material change without notice. ©2009 SPX Cooling Technologies, Inc. Printed in USA
Manual
