electric motor queston

i installed a new pool pump motor and didn't switch the internal switch on the back of the housing from 230 to 115 volts. the pump was running fine for a couple days but now it just hums and the shaft won't turn. it isn't seazed up because i can turn the shaft freely with my hand. any idea if i killed the motor or am i missing something? the motor is an Emerson 1.5 hp

Your new motor is probably burnt out.
Some types of AC motors draw more current when their voltage is low. Maybe your motor drew twice as much current as its wires were designed for and burned. It hums because not all of its coils are burned.

Although you might be able to re-wind it, the chances are you can't so you're only option is to buy a new one.

I suppose you've learnt a lesson, always check the voltage switch and read the manual before you use something.