You would use a 5 inch sheave.
Over driven blowers are geared to spin higher rpm then the motors actual rpm. Vise versa for Under driven.
calculating sprocket RPM is very easy if you know what the RPM of the drive sprocket is. If you know that then it is a simple fraction problem. If you make the drive gear the numerator or the top part of the fraction and the driven gear the denominator or the bottom part of the fraction (DRIVE/DRIVEN) I.E. if the drive sprocket has 25 teeth and your driven sprocket has 100 teeth (25/100) that will reduce to (1/4) or a 4:1 ratio. So if your drive sprocket is spinning at 1000 RPM then your driven sprocket will be spinning at 250 RPM. You can plug your specific sprocket tooth count into that equation and come up with the right answer.
Drive Pulley = pulley on motor Driven Pulley = pulley on blower First determine your Ratio - divide large pulley size by small pulley size this will give you gear ratio, Example 2" drive pulley and a 4" Driven Pulley = 2:1 gear ratio If you know your motor shaft RPM divide that number by the ratio to get the RPM of the driven pulley, if your shaft rpm is 1800 rpm you would divide 1800 by 2 which would = 900 rpm on your driven pulley if your drive pulley is larger than than your driven pulley you multiply the rpm by the ratio example 1800 rpm x 2 = 3600 rpm
What does a winch and sheave
The sheave height is the distance between the shortest distance from the tip of the sheave (commonly called a "boom") and the ground. It is common to discuss the sheave height with respect to a piece of equipment and get a number which is the maximum sheave height.
For a pulley, it is driver RPM x driver diameter = driven RPM x driven diameter. Keep in mind that the diameter you should use is the diameter where the belt is riding in the pulley. For instance, an A belt in an AB pulley will ride lower in the pulley than it would in an A pulley. For sprockets, the formula is the same, but replace the diameter with # teeth. It looks like this. driver rpm x # teeth of driver sprocket = driven RPM x # teeth of driven sprocket
The Sheave Height of a Digger Derrick varies. But the average of the Sheave Height for most Digger Derrick goes from 45 till 57.5.
To determine the speed of rotation of a gear driven by another gear, you can use the gear ratio formula: Gear Ratio = Number of Teeth on Driven Gear / Number of Teeth on Driving Gear. In this case, the gear ratio is 40/20 = 2. Since the driving gear is rotating at 10 rpm, the driven gear will rotate at 10 rpm / 2 = 5 rpm.
you can use this system for reversing the direction of the drive sheave where material and weight may cause adverse effects to the machine.. ideally used for low RPM applications
To calculate burst RPM (rotations per minute), you need to know the burst speed of the machine in revolutions per second. You can then multiply this value by 60 to convert it to RPM. The formula for calculating burst RPM is: Burst RPM = Burst speed (revolutions per second) * 60.
1750 x 8/17 = 823.5 rpm