My target makes a humming sound then trips breaker,whats up?

A number of issues could cause that.
Door switch contaminated.
Turntable motor contaminated.
Magnetron failed.
Capacitor failed.
Diode pack failed.
Pick one and investigate bearing in mind there are LETHAL voltages inside the case!!!

time to replace Microwave.

test motor movement jammed or seized

probably not
if it was blown it would be tripping circuit breakers and not making a sound
I would be checking/replacing the start /run capacitor for the motor

Drag on the Motor is increasing the HEAT, the HEAT is what is causing the trip. Your motor sounds like it is getting weak.

try replacing capacitors sounds as if it is drawing to many amps trying to start

Could be 2 reasons. If the pump is on and you are hearing a humming noise, it could be a bad capacitor. The capacitor is what starts the pump by giving it a kick start of electricity.

It could also be a seized motor, when it tries to start, it will also make a humming sound, and eventually trip the breaker.

The way to test if it seized is try to turn the motor by hand (Make sure the power is off). If the motor can't turn then it's seized.

12 years is middle aged for an appliance, but the problem is probably one of the garbage disposal big three: a tripped circuit breaker, a tripped reset button, or a jammed disposer. With the breaker turned off, make sure the disposer's shaft rotates freely. On most disposers there's a hole in the bottom middle where you can insert an allen wrench that you're probably find under the sink and rotate the shaft manually to free jams. But, for the love of God, only do this with the breaker turned off and make sure you remove the wrench (or broom handle if you have to go from the top) from the disposer before turning it on. Make sure the reset is pushed down until it clicks if it's tripped, and, since circuit breakers get old and stick, you'll have to turn the breaker all the way off and back on to make sure it's not tripped. If the disposer hums but doesn't turn when you turn it on, check to see if it's jammed. If it turns freely but hums and doesn't start then the starter circuit on the motor is bad. If the breaker and reset button are ok and it doesn't even hum when you turn it on, you'd want to check the disposer to make sure it's getting power. You can find a little electrical reader at walmart for $5 that works like a geiger counter and will beep when it gets close to something that's receiving power. The switch may be worn out, but really the disposer's motor failing is probably the least likely thing. But please get a qualified electrician out there if you don't know what you're doing. There's a reason that it requires a license.

check impeller by turning shaft with pliers sounds as if its stuck do this while of and try to restart

Ifs its a small humming sound,then its the contactor pulling in. But if it a loud humming sound then its the compressor kicking in. and the fans not, try to take something long and turn the blades on the fan, if it takes off and run then your capacitor is shot or swollen at the top,which was cause by power surge. Take-off and replace with the same mfd. writings ,on the outside of can. Also check for blown fuses or tripped breaker . the fuses should be in the disconnect box on the wall, or the breaker in the breaker box.. Older house has fuses instead of a breaker box!