SINGLE GROOVE PULLEY Brand new. Fractional HP, single groove, cast iron pulley with keyway and one set-screw. For use with type "A" and "B" belts. Fully balanced.
Outside Diameter 3.75"
Belt Type A (1/2") Datum Diameter 3.00"
Belt Type B (5/8") Datum Diameter 3.40"
Shpg. 2 lbs.
Outside Diameter Diameter measured at the outside of the pulley.
Datum Diameter The datum diameters are an industry standard reference point used for calculations such as center distance and belt length. The datum system replaces the pitch system for classical belts and pulleys to compensate for differences in manufacturers construction of belts.
I need a pulley that will have an outsde diameter of 3.75" with a 4L belt. I am tryin to increase fan speed from a 3" to 3.75" on motor shaft. Tim
A: The back side of a 4L belt will ride at roughly 3.875" on item 1-BK45, and 3.575" on 1-BK40. Keep in mind that the increase of horsepower demand is the cube of the quotient of the two different speeds multiplied by the original horsepower, and can lead to dramatic changes in demand with a relatively small increase in speed. Research 'Basic Fan Laws' on the internet: a quick example showed that with the 19% increase in speed such as you are planning changed the horsepower draw of a fan which required a 1/2 hp to over 3/4" hp. When the motor power is not increased accordingly, this can lead to issues.