User Manual
7
Establish a schedule for inspecting all parts of the fan. The frequency of inspection depends on the operating conditions and 
location of the fan. 
Inspect fans exhausting corrosive or contaminated air within the first month of operation. Fans exhausting contaminated air 
(airborne particles) should be inspected every three months, or sooner. Regular inspections are recommended for fans 
exhausting non-contaminated air. 
It is recommended the following ins pection be conducted twice per ye ar. 
  Inspect bolts and setscrews for tightness. Tighten as neces sary. Worn setscrews should be replaced immediately. 
  Inspect belt wear and alignment. Replace worn belts with new belts and adjust alignment as needed. See Belt and 
Pulley Installation on page. 4. 
  Inspect springs and rubber iso lators for deterioration and replace as needed. 
  Inspect for cleanliness. Clean exterior surfaces only. Removing dust and grease on motor housing assures proper 
motor cooling. Removing dirt from the wheel and housing prevents imbala nce and damage. 
Lubricants 
M.K. Plastics uses petroleum lubricant in a lithium base. Other types should not be used unless the bearings and lines have 
been flushed clean. If another type of grease is used, it should be lithium-based grease conforming to NLGI grade 2 
consistencies. 
A NLGI grade 2 grease is a light viscosity, low-torque, and rust inhibiting l ubricant that is water resistant. Its temperature range 
is from –30ºF to +200ºF and capable of intermittent highs of +250ºF. 
Motor Bearings 
Motor bearings are pr e-lubricated and seale d. Under normal condit ions they will not require further maintenance for a period o f 
10 years. However, it is advisable to have your maintenan ce department remove and disassemble the motor, and lubricate the 
bearings after 3 years of operation in excessive heat and or in a contamina t ed air stream consisting of airborne particles. 
Fan Bearings 
RKW fans normally have permanently sealed flange-bearings that do not require greasing. However, some fans could have 
greasable pillo w-block bearings. These bear ings are lubricated through a grease fitting on the bearin g and should be lubricate d 
by the schedule, Conditions Chart. 
Conditions Chart 
RPM  Temperature  Fan Status  Greasing Interval 
100  Up to 120ºF  Clean  6 to 12 months 
500  Up to 150ºF  Clean  2 to 6 months 
1000  Up to 210ºF  Clean  2 weeks to 2 months 
1500 Over 210ºF  Clean  Weekly 
Any Speed  Up to 150ºF  Dirty  1 week to 1 month 
Any Speed  Over 150ºF  Dirty  Daily to 2 weeks 
Any Speed  Any Temperature  Very Dirty  Daily to 2 weeks 
Any Speed  Any Temperature  Extreme Conditions  Daily to 2 weeks 
For best results, lubricate the bear ings while the fan is in operation. Pum p grease in slowly until a slig ht bead forms around the 
bearing seals. Excess ive grease can burst seals resulting in high operating temperatures, thus reducing bearing life. 
In the event the bearing cannot be seen, use no more than three injections with a hand-operated gre ase gun. 
Motor Service 
Should the motor prove defective within one-year period, contact M.K. Plastics directly, or your nearest motor service 
representative. 
Changing Shaft Speed 
All belt driven f ans with motors up t o and including 3 hp (182T max.) are equipped with variable pitch motor pulle ys. To change 
the fan speed, perform the following: 
1.  Loosen setscrews on driver (motor) pulley and remove key, if equipped. 
2.  Turn the pulley rim to open or close the groove facing. If the pulley has multiple grooves, all must be adjusted to the 
same width. 
3.  After adjustment, inspect for proper belt tension and alignm ent. 
Speed Reduction 
Open the pulley in order that the belt rides deeper in the 
groove (smaller pitch diam eter). 
Speed Increase 
Close the pulley in order that the belt rides higher in the 
groove (larger pitch diameter). Ensure that the RPM limits 
of the fan and the horsepower limits of the motor are 
maintained, which can be read on the motor name plate. 
Pulley & Belt Replacement 









