Most drives have two sheaves, one on the motor and one
on the driven machine. The motor base usually has slotted
holes to allow for adjustment toward and away from the
driven machine. Loosen the motor hold down bolts and
move the motor toward the drive machine to the inner end
of the adjustment to release tension on the belts. Use a pry
bar against the motor base, if needed. The belts should
now be quite loose. If the drive has an idler instead of an
adjustable motor base, loosen the hold down bolts and
swing the idler away from the belts, allowing them to hang
loose. Be sure to use all the adjustment in the drive to
loosen belts completely.