Dryer won't run right

dryer does not seem to want to start. I have removed belt and drum and the motor turns freely by hand and with electricty. If the dryer does start it only runs for maybe 10 mins and then cuts off, if you wait thirty mins, it might start back on another ten mins. when the dryer won't start it just hums when the start button is pressed, if you hold in start button it seems to kick a breaker or something inside the dryer and then you have to wait for it to "reset" it's self. the heating element comes on and seems to be working fine.