LE6XRT ERV
RENEWAIRE.COM
INSTALLATION, OPERATION AND MAINTENANCE MANUAL
1.800.627.4499
32
MAINTENANCE
10.5 ELECTRIC MOTOR MAINTENANCE
The most important issues in motor maintenance are:
• Belt condition and belt tension
• Sheave condition
• Motor cleanliness
• Motor lubrication
10.5.1 Belt Tension
10.5.2 Sheave Condition
10.5.3 Motor Cleanliness
10.5.4 Motor Lubrication
Premature or frequent belt failures can be caused by improper belt tension (either too loose or too
tight) or misaligned sheaves. Abnormally high belt tension or drive misalignment will cause excessive
bearing loads and may result in failure of the fan and / or motor bearings. Conversely, loose belts will
cause squealing on start-up, excessive belt flutter, slippage and overheated sheaves. Both loose and
tight belts can cause fan vibration.
When replacing belts on multiple groove drives, all belts should be changed to provide uniform drive
loading. Do not pry belts on or off the sheave. Loosen belt tension until the belts can be removed by
simply lifting the belts off the sheaves. After replacing belts, ensure that slack in each belt is on the
same side of the drive. Belt dressing should never be used.
The proper belt setting is the lowest tension at which the belts will not slip under peak load operation.
For initial tensioning, set the belt deflection at 1/64-inch for each inch of belt span (measured half-way
between sheave centers). Example: If the belt span is 16 inches, the belt deflection should be 16/64
inch, or 1/4 inch (using moderate thumb pressure at mid-point of the drive). Check belt tension two
times during the first 24 hours of operation and periodically thereafter.
Measure
to Nearest Inch
(Belt Span)
Deflection Equals 1/64 Inch
Per Inch of Belt Span
Do not install new belts on worn sheaves. If the sheaves have grooves worn in them, they must be
replaced before new belts are installed.
Removing dust and grease buildup on the motor housing assists proper cooling. Never wash-down the
motor with high pressure spray.
High efficiency motors have unique maintenance requirements that vary from motor to motor. Many
smaller horsepower motors have sealed bearings that do not require periodic greasing. Larger
horsepower motors come equipped with grease fittings. Before greasing any motor, consult the motor
manufacturer’s web site to determine the correct maintenance and greasing schedule.
Each motor manufacturer specifies the frequency of maintenance and the amount and
type of grease to use on the bearings. Do not mix different types of grease. Check the
manufacturer’s web site for each specific motor.
Fan Belt Tensioning
