One shaft is fixed and the other is moveable. The variable speed pulley is normally mounted on the moveable shaft and a fixed diameter sheave on the stationary shaft. By using an adjustable motor base, speed variation of the driven shaft is accomplished by mechanically changing the center distance between the shafts. An increase in center distance will pull the belt to a smaller diameter in the variable speed pulley. This increases the drive ratio and reduces the driven shaft RPM. A decrease in center distance allows the spring-loaded pulley faces to close and push the belt to a larger diameter.
The TBR Series of pulleys are Adjustable Center Distance Drive pulleys using standard V-Belts. The horsepower range is fractional to 5 HP at 1750 RPM. They have single face movement to provide greater economy on longer center distance V-V drives where absolute belt alignment is not critical. Their through bore construction allows mounting from either end. Hi-Lo’s torque sensing mechanism controls belt tension with load requirement.
Two Face Movable Design (for standard V-belts)
Maintains belt alignment between the variable speed pulley and the companion sheave. This is an important feature with close center distance drives. Models 257 and 265 are an exception, however, and should use recommended shaft center distances.
Uses Variable Speed belts. Maintains belt alignment between the variable speed pulley and the companion sheave. The wider varible speed belts allow a greater speed ratio change than standard V-belts while maintioning a match between the included angle of the pulley gaces and the belt.
The driver and the driven shafts are both stationary. The drive consists of two adjustable pitch diameter pulleys. One pulley is manually controlled by means of an adjusting screw. The driven pulley adjusts automatically to belt movement. Speed variation is accomplished by turning the adjusting screw in the mechanical pulley, causing the pulley faces to move in or out and, therefore, changing the pitch diameter at which the belt rides. This causes a compensating opposite change of the pitch diameter in the automatic pulley, usually mounted as the driven pulley. The RPM of the driven shaft changes with the change of ratio in the pitch diameters of the two pulleys.
75–5 hp Fixed Center Distance Drives
MCV series pulleys are Fixed Center Distance Drive type pulleys. The MCW pulleys use Standard V-Belts and have horsepower rating from .75–5 HP. The automatic pulleys have Hi-Lo’s torque-sensing mechanism to control belt tension with load requirement.
1–7.5 hp Fixed Center Distance Drives
Standard V-Belt and Variable Speed Belt Pulley Drives
MCW series pulleys are Fixed Center Distance Drive type pulleys. The MCW pulleys use Variable Speed Belts and have horsepower rating from 1–7.5 HP. The automatic pulleys have Hi-Lo’s torque-sensing mechanism to control belt tension with load requirement.
Hi-Ratio Compound Pulleys for ¼ and ½ hp. drives provide economy and exceptional efficiency at speed ratios up to 7 to 1. Pulley faces are made of highly durable plastic containing special additives to insure long service life.
Get the right collet to match shaft size.
Hi-Lo Motor Bases for Adjustable Center Distance Drives have been designed to accommodate NEMA motor frame sizes 48 through 286T, with rigid steel construction, and lube free bushings in the motor mount plates for easy adjustment and greater wearability on the 214, 254 & 284 models.