Hello i have a Hayward super ii pump 3hp.  About 3 weeks ago the pump tripped the breaker.  I went out and bought a new start capacitor and it worked fine for about a week.  Then it tripped the breaker again.  I pulled off the motor off and throughly cleaned inside the end cap.  It was super dusty.  Checked the capacitors and they were good.  Put it back on and it worked great for about 2 weeks.  It tripped the breaker again this weekend.  Started it up it hummed and tripped.  Checked capacitors and they were good. The impeller is not locked up.  I assume the motor just finally died?? Any other ideas to try? Pump that it's only about 3 years old.  The guy we bought the house from had it installed when we moved in. 

My pool is about 15000 gallons.  I think the 3hp pump might be overkill from what i've calculated and read.  Could also be the reason it may have burned up? I have 2" pipes for suction.  I have a californian C5520CP filter.

If it is too big, from what i read a 1.5 would be perfect but I would need to swap out the impeller and diffuser?  Is that right?  Would the motor fit into SP3025X30AZ?  Or just but a 3hp motor and be done with it?

Thank you!