Motor Maintenance; Structural Maintenance - Johnson Controls York Stack Fan Operating Manual

YORK ® STACK FAN
Motor and Structural Maintenance

MOTOR MAINTENANCE

The three basic rules of motor maintenance are: keep the motor clean, dry and properly lubricated.
Keeping motors and windings clean is important as trapped dirt and dust may impede air flow and heat
convection causing motor windings to overheat possibly leading to premature failure. Blow dust and dirt
out of windings and off the motor periodically. Use low pressure (50 psi) airstream to prevent winding
damage. Keep the areas surrounding the motor clear so the air can circulate through the motor cooling
fan.
Motors should be kept dry to avoid electrical short circuits. Motors kept in storage for long periods of
time can have moisture condense on the windings. Be certain the motor is dry before using.
Some smaller motors are permanently lubricated. Motor bearing lubrication, if required, must follow
a rigorous schedule. Motors less than 10 hp running eight hours a day in a clean environment should
be lubricated once every five years; motors 15 to 50 hp, every 3 years; and motors 50 to 150 hp,
yearly. See motor manufacturer specifications for recommended greases. For motors in a dusty or
dirty environment or running 24 hours a day, divide the service interval by 2. If the environment is very
dirty or high temperatures exist, divide the service interval by 4. Lubrication requirements are normally
attached to the motor. Do not over-lubricate.
The major cause of motor bearing failure is contamination of grease, insufficient grease, over lubrication,
and incompatibility of grease. If a fan is to be stored for any length of time and the bearings are re-
greasable, the motor bearings should immediately be filled with grease while rotating the fan and then
the bearings should be re-greased and rotated monthly. This will prevent moisture, which condenses
within the bearing, from corroding the raceways.

STRUCTURAL MAINTENANCE

All structural components or devices used to support or attach the fan to the isolation base, or other
structure should be checked at regular intervals. Vibration isolators, bolts, foundations, etc, are subject
to failure from corrosion, erosion, and other causes. Improper mounting can lead to poor operation
characteristics, fan fatigue, and failure. Check components for corrosion, cracks, or other signs of
stress.
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