Blows breaker only when starting with partia pressure in tank.
Starts fine with empty tank.
It kind of chugs a little like starting your truck in second gear then pops breaker if any pressure in tank.
I have disconnected hose to unload valve so there shouldn't be any back pressure.
If started on empty tank it runs perfect to 120 psi so I think motor is fine.
Take cover off and motor and piston turn with zero resistance.
I think it is starter caps but they tested good at motor shop.
Please empty the tank, start the compressor, monitor the unloader valve, and comment here as to whether it works or not.