In Reply to: Voltage question posted by Philny on May 03, 2019 at 20:36:25:
3hp at 230V =17 amp load
3hp at 115V =34 amp load
All motor loads must allow for starting load called “locked rotor “ amps. A 30A single pole will not hold at 115V, even with capacitor which your 3hp motor has I would bet.
Proper wiring would be 30a 2 pole breaker with #10 wire minimum on 230 volts.
There’s a lot more to it in the code but that’s the bottom line.