AEC Colortronic MTF 3000 Series Granulator - Manual (Page 17)

7.0 Motor and Belts - Service Instructions
7.1 Procedure
Prior to startup of this machine, it is recommended that the drive belt tension be checked for
proper “RUN IN” deflection force as listed in column “A” next page.
After the equipment has run between 24 and 48 hours, drive belt tension must again be
checked for proper “RUNNING” deflection force as listed in column “B” next page.
A V-belt drive will successfully transmit its rated capacity if the belts are properly tensioned.
The method of tensioning is explained here in detail for your information.
1. Verify that the alignment of the pulleys is correct. Utilizing a straightedge of sufficient
length to span from one pulley to the other, place it along the sides of both pulleys. The
side of each pulley should contact the straightedge.
2. Measure the belt span (figure 1).
3. Using a spring scale, apply a perpendicular force to any ONE of the belts at the mid point
of the span.
4. Measure the force (lbs) required to deflect any one of the belts 1/64 of an inch for every
inch of span. For example: the deflection for a 32” span would be 1/64” x 32”, or 1/2”.
The force required to deflect the belt is listed in the Table below and it requires selecting
the correct belt section and corresponding smallest sheave diameter for the arrangement in
question.
5. The motor position should be adjusted until the actual deflection force matches the forces
listed in column “A” for new belt installations.
6. There will normally be a drop in belt tension during the first 24 to 48 hours of operation
due to belt stretch and the belts seating themselves in the sheave grooves.
7. After the initial “RUN IN” period the machine should be stopped and the belts should be
re-checked for tension. The motor position should be adjusted until the deflection force
matches the values in column “B”.
8. In no case should the belts be overtensioned as this can significantly reduce belt life
and/or bearing life.
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