Why will lower voltage capacitor work my pump?

[Albgoblue]

It appears my pump is fixed and the issue solved. There is indeed only 120 volts coming into the pump and the pump was wired for high voltage. I switched the pump wiring to low voltage and everything is now running great with the original 370 vac capacitor. The pump ran all night and has not shut down at all. The question is why did it run for 2 years wired incorrectly and why did the pool people who installed the pump not switch the wiring to the correct setting? I guess we do not need to answer that. Anyway, thanks for your responses and help. I am happy I have a running pump again.

[PoolDoc]

There is indeed only 120 volts coming into the pump and the pump was wired for high voltage. I switched the pump wiring to low voltage and everything is now running great with the original 370 vac capacitor. ---- The question is why did it run for 2 years wired incorrectly and why did the pool people who installed the pump not switch the wiring to the correct setting?

For the record -- and for all the other people who may read this thread in the future -- I'm very doubtful that the pump actually DID run for years wired 240V, but supplied 120V. As far as I know, with most pool motors, this is not possible.

I'd guess that somewhere in the assembly and repair process, some wiring got switched around.