difference between a A and B pulley

[Cord]

I have a compressor that I want to drive with an engine. It has a two groove pulley. I measure the grooves as being 1/2" wide. I think this is a type A belt (please confirm). I see some pulleys on Ebay that are listed for a type B belt. Obviously the A belt will sit deep into this pulley. Too deep? I'm thinking that the center to center distance of the grooves will be wrong so the belts won't run parallel to each other. Thoughts?

 

[SandburRanch]

I have a compressor that I want to drive with an engine. It has a two groove pulley. I measure the grooves as being 1/2" wide. I think this is a type A belt (please confirm). I see some pulleys on Ebay that are listed for a type B belt. Obviously the A belt will sit deep into this pulley. Too deep? I'm thinking that the center to center distance of the grooves will be wrong so the belts won't run parallel to each other. Thoughts?

I believe your thoughts are correct. Google has a lot of belt information from various manufacturers and suppliers. Attached is one of those bits of information. Gates also has a good chart but I couldn't read the small print on their pdf file.
Notes on Pulleys and Belts

 

[chrisw212000]

A belt will be half inch wide. B section belts are 5/8.

 

[GT2]

We often use " A B " pulleys, 1/2 or 5/8" in the same groove.

 

[tpulley]

I can really only attest that the pulley's around my house are quite a bit wider than the 1/2 or 5/8 listed here. So they, (we), (me) must be either AAA or ZZZ Pulley's.

It also appears that when two or more pulley's are used together they become stronger than the independent pulley's this is often referred to as synergy.

The older pulley's seem to be good at idle speeds as opposed to faster working conditions.

 

[kevinj]

I have a compressor that I want to drive with an engine. It has a two groove pulley. I measure the grooves as being 1/2" wide. I think this is a type A belt (please confirm). I see some pulleys on Ebay that are listed for a type B belt. Obviously the A belt will sit deep into this pulley. Too deep? I'm thinking that the center to center distance of the grooves will be wrong so the belts won't run parallel to each other. Thoughts?

You need to pay attention to the PD on the combo pulleys. They drive at different diameters.