I would have to know a lot more about your compressor and the current motor horsepower, rated amp draw at full load (FLA) etc... BUT, you could use a smaller motor by going to a smaller drive pulley, as that will turn the machine slower and use less amperage at the same voltage. The correct size depends upon several factors which I need to know first.
Can you provide all the info on brand, model number and rated volume output, outside diameter of the pulley that is on the compressor, etc. Also all the info off the motor plate, specifically the horsepower or other equivalent rating, full load amps, pulley outside diameter and any other info you can come up with. We could probably decide on a suitable smaller motor once you also determine the amperage available at your power supply. Lot's of stuff to find out, but that's the only way I might come up with a suggestion for you.
Also a good photo of the unit might be a big help along with close ups of the motor info plate and compressor plate if any.
The older I get the better I was.