force required to spin vaccuum fan

[martin417]

Originally Posted by Bruceb

Martin, how did you adapt that belt sprocket to the FP motor shaft?
Bruce

It's just a timing sprocket from Stock Drive Products. It has a setscrew to hold it on the shaft. If I remember correctly, we may have had to enlarge the bore slightly due to the knurling on the FP shaft.

[martin417]

Another though on vacuums: some are single stage, and some have two or more. A single stage will have one rotating disk, while a two stage (like the one we used) will have two rotating disks separated by a stationary flow straightener. A single stage will flow more air at a given size and power, while a two stage will create a higher static pressure differential.

If you can get a two stage, you will probably be better off in this game because the ball area is relatively small.

[Bruceb]

What kind of devices have a 2 stage vac?
Bruce

[martin417]

Originally Posted by Bruceb

What kind of devices have a 2 stage vac?
Bruce

Ours came from a shop vac, but my old Rainbow at home has a 2 stage impeller also.

[Bruceb]

Martin, what belts did you use. Is the cheapest o.k.?
Bruce

[DonRotolo]

Originally Posted by Bruceb

Is the cheapest o.k.?

Cheapest is always just that: Cheapest. Over the years we have found that Best tends to work better and last longer. Build using the highest quality components you can afford.

Of course, for prototypes, cheap is usually fine.

[martin417]

Originally Posted by Bruceb

Martin, what belts did you use. Is the cheapest o.k.?
Bruce

Avoid "shade tree engineering"! Don't just guess and try it, the build season is too short!

Belt manufacturers publish data on capacity of belts, advantages of construction and materials, etc. The data is often in the form of a graph, plotting belt capacity (in horsepower) against the speed (in RPM) of the fastest pulley. do not exceed the spec.

You should also look at the max torque. You will probably have to ramp up up the speed of the motor to avoid slipping the belt or the pulley.