Bandwheel Drive Belt One belt or Two.

[William1961]

Bandwheel Drive Belt question.
I am presently building a Bandsaw Sawmill.
I am using a 2 groove pulley on the engine and a 2 groove pulley driving the bandwheel.


I would like to know if a single belt is ok or would a 2 belt arrangement work better.
In other words 2 belts side by side.

I am asking this question because I would really like to put a external alternator on this bandmill using one of the grooves on the engine pulley.

I like the idea of a double belt system driving the bandwheels.
My only other route would be to put a shaft on the flywheel side of the engine.
This would only drive a 40 amp alternator with belt tensions within reason.

Thanks.

[Ianab]

Engine power?

With a smaller engine you can get away with one drive belt. My mill has 13hp and uses 2, larger mills can have up to 3 belts. 

Might be better to put a triple pulley on the motor, and have 2 belts to the drive wheel and one to the alternator?

[Den-Den]

Belt power capacity is very dependent on pulley size.  Larger pulleys mean each belt can transmit more power.  Just as an example, a single "B" belt on a 4.5" diameter pulley is barely enough on my 23 hp engine.

[William1961]

Thanks for the reply.
Engine is a 20 hp Honda.
Looks like I will try and find a 3 groove pulley for the engine.

[dustyhat]

Go with two . three if you can.

[mike_belben]

Google belt power chart and youll find the ratings.  It goes up as you travel down the alphabet, and up as the pulley diameter and belt count increase.

Id just center and weld a 3rd sheave onto your double to drive the alternator. Especially if your alt has an A belt and your motor is running B's.  Mount and tension the alternator opposite the direction of the saw wheels.  This will actually help counteract the saw belt tension and help increase crankshaft bearing a life a little bit.  Will take some deflecting load off the engine output shaft.