"Jim Wilkins" wrote in message ...

"Hul Tytus" wrote in message ...

Does anyone know which of the small v belts would be used with
a 1.5 hp 1700 rpm motor? My 9/20 lathe with a 3/4 horse power
motor uses one with a width of approximately 1/4 inch. Next size
up for 1.5 hp?

Hul

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https://www.contractingbusiness.com/...ement-fan-belt

My first choice for a new installation is the B sized belts and pulleys the
hardware store carries, mostly due to their easy availability. One seems
adequate for the 240V, 15A 3450 RPM motor on my cobbled-together 60 gallon
air compressor, though it did stretch and loosen at first. If it fails I'll
put a smaller pulley on the motor to reduce the pump speed. The one on it
now is 4", the proper size to match the nominal pump speed would be 3.8",
and I bought a 3.5" just in case.

The B belt on my 6.5 HP "hand-crafted" (home-made) sawmill has held up well
through several months of daily use. I did have one fail on the home-made
hydraulic pump drive on my 18 HP tractor, but it had lasted a while and
slowing the pump by giving it a larger pulley cured the problem. Edge cords
broke and caused the belt to roll sideways where it lacked the grip to drive
the pump.

My 3HP snow blower takes an A size belt, the 7 HP one uses B belts.

The rated horsepower can be calculated if you have the belt data, which is
unlikely for hardware store belts.
https://www.engineersedge.com/belt_d...-design-hp.htm

I've run the numbers for shaft fatigue life and Lovejoy coupler rating for
which all the data is available, but just adjust or replace belts with
better Gates ones as needed if I run them too close to their capacity. Like
WW2 aircraft engines I use the strengthen-whatever-breaks design principle
rather than trying to measure and calculate everything, especially peak
dynamic loading.

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I should have looked up the sizes. Put 3L where I wrote A and 4L for B.