SPX Cooling Technologies HP7I - Manual (Page 4)

Caution
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:
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
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.
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—
HP7i—and diameter are required when ordering replacement parts.
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.
VOLTS
N
= Nameplate Volts
AMPS
N
= Nameplate Amperage
HP
N
= Nameplate Horsepower
DENSITY
D
= Design Air Density
HP
C
= Corrected Horsepower
VOLTS
A
= Actual Volts
AMPS
A
= Actual Amperage
DENSITY
A
= Actual Air Density
VOLTS
A
× AMPS
A
× DENSITY
D
VOLTS
N
× AMPS
N
× DENSITY
A
HP
C
= × HP
N
Manual 92-1471E
7401 WEST 129 STREET | OVERLAND PARK, KANSAS 66213 UNITED STATES | 913 664 7400 | [email protected] | 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