Air Compressor Pump / Motor Question

[Doubled33]

In looking at cut-sheets of pumps most manufactures give a HP range the pump will work with. Am i correct in thinking that the pump pulley is the same size and the motor pulley is what changes size relative to the HP? For example a QR 350 shows to need 5 to 15 HP and has a rpm range of 400 to 940.

 

[Milton Shaw]

Pump pulley is normally the flywheel and cooling fan so it doesn't changes sizes. The motor pulley is sized from horsepower and rpm charts that usually come with the new compressor. Too low or too high will damage the compressor as too low it doesn't splash the oil in the crankcase right.

 

[Walkers]

Yes, lower hp, slower speed, smaller pulley.