Ryan_J,
Isn't there an exception inf 430.6 for appliances that include motors, where you get to use the nameplate amp rating _of the appliance_ rather than the table value?
drgnz23,
The wire _inside of an appliance_ is rated under different rules than the wire used for running circuits in walls. This is because wire is not limited by _current_, but is instead limited by temperature. The temperature is caused by _heat_, which is produced when current flows, and _heat disspiation_, which depends upon the surroundings. When you have a better idea of the heat dissipation available, you can use thinner wire, and the UL listing (not the NEC) determines what wire is appropriate in an appliance.
If you calculate out the values in table 430.148, the VA of the circuits required is roughly _double_ the wattage of the motors described (1 hp is 746 watts). This doubling is required because of inefficiency, power factor, and overload requirements. With an appliance, all of these factors are better controlled than with a general purpose motor.
If possible, you should consult the manufacturer of the appliance. They may have a recommended or required conductor ampacity, disco size, and OCPD requirement. This should be reflected on the nameplate, but the instruction manual is probably a clearer source.
Lastly, the current reading that you get when running the compressor will depend upon the load on the motor; in particular the pressure in the tank. The higher the pressure, the more work the motor will do, and the greater the current. I can tell you right now that 12A at 240V is _not_ 7hp, but less than half that depending upon power factor and efficiency.
-Jon
