220/240
For the most part, the difference in voltage is just an upgrade in the U.S. power grid. Home voltage is around 120v now, so the two phases together will be 240 v similar to the old 115v/230v system.
If the motor has two capactors on top, one is a start capacitor and the other is a run capacitor, common on larger horsepower motors, especially compressors where you have a lot of starting torque required.
Check the voltage on the incoming line side at the pressure cutout switch to see if you have 240 v. If not, check each phase to neutral to be sure you have 120. If both phases show zero, you have a problem either with the wiring or back at the service panel. If one is dead and the other good, you have a blown fuse or a bad circuit breaker. If you have 240v at the incoming side of the cutout switch, check on the motor side of the cutout switch. If there's 240v there, you have a bad motor or it's not wired right -- hopefully the latter is the case. You'll have to check the motor's nameplate to find the wiring diagram and then check "under the hood" to see if it's correct for 240v. Be sure the power is off at the service panel when you're fooling around with this end of things. If the voltage at the motor end of the switch measures zero, check each side to ground. If one is zero and the other is 120v, you have a defective switch. If both are zero, either the switch is defective or there's full pressure in the tank and the switch is in the cutout position.
You can check the switch by jumpering across the kpressure switch contacts, one wire from side "A" of the incoming phase to side "A" of the motor and the other wire from side "B" of the incoming phase to side "B" of the motor. Turn power back on at the breaker panel. If the compressor starts up, you have a bad pressure switch. Turn power back off and remove the two jumper wires.
Dean