Fig. 1,381.—Sub-base and ratchet device for moving alternator to tighten belt. A ratchet A, operated by lever B, works the block C by screw connection, causing it to move the block. The latter, engaging with the frame, causes it to move, thus providing adjustment for belt. After tightening belt, the bolts D, which pass through the slots in the sub-base, are tightened, thus securing the machine firmly in position.
Ques. What provision should be made in the design of an alternator to adapt it to belt drive?
Ans. Provision should be made for tightening the belt.
Fig. 1,382.—Allis-Chalmers pedestal type, belted alternator. The bearings are of the ring oiling form with large oil reservoirs. The bearings have spherical seats and are self aligning.
Ques. How is this done?
Ans. Sometimes by an idler pulley, but usually by mounting the machine on a sub-base provided with slide rails, as in fig. 1,381, the belt being tightened by use of a ratchet screw which moves the machine along the base.