"Morgans" wrote in message
...

"Drew Dalgleish" wrote

The longest one slips on both pulleys.

Think about it for a moment...

If one belt is a little longer, it would not be able to carry as much
power, because it is not as tight as the others.

The others tight belts will carry nearly all of the power, up until the
point where they can not carry all of the power. Then the tight ones will
start to slip.

If the long belt is not able to carry power, but the short tight ones can
carry all of the power being produced, then there will be no slippage.

It is counter intuitive, but that is the situation. If there are 4 belts,
and three can carry all of the HP, and the 4th one is loose, it will not
slip. It will not be carrying any power, though.

If all 4 belts have to be pulling equal load to be able to carry all the
HP being produced, and one belt is loose, then the tight 3 will slip,
because the 4th loose belt can not carry its share, and is slipping.

In my experience of multi V-belt farm type equipment, if you start with 4
new identical belts, and they are a well matched set of identical lengths,
they all will pull evenly. If one is loose, they will slip like I said
above, and will often times stretch to be more closely matched and start
pulling more evenly, if there is enough tension to pull them back tight,
and you do not completely glaze the belts from the initial slipping.

I bet the multiple V-belt reduction unit is running at a very high
percentage of maximum HP recommended by the belt manufacturer. It would
be more likely to smell like burned belts than most farm type
applications, where the loads are kept more conservative by just adding
more belts.
--
Jim in NC

Thanks Jim,

That is all in keeping with what I had always understood, and also makes a
great point about conservative versus optomistic designs.

Peter