get a GOOD tech out and have him check it out, it is a possibility that the capacitor may be going out, or possibly by now, the motor windings could be burnt up. but it should have been checked out as soon as the breaker was starting to snap, what is happening some thing is either shorting out or not running efficient and causing the motor to over work and pull to much electrical power, there is a possibility the charge of refrigerant is over what it should be. could be a loose connection or a wire that is wore through and the heat expands or changes some thing that moves it,
IT is even possible it is a weak breaker, (I would replace the breaker regardless if it has tripped that many times) but with out an amp check of the system running you would never know.
HAVE IT CHECKED OUT BY SOME ONE WHO KNOWS THE SYSTEMS.
ANY TIME A BREAKER IS TRIPPING IT MEANS SOME THING IS WRONG !!!!!!!!!!!!
either the breaker is going, (some old breakers have been know to burst in to flames)
or the compressor or fan if on same circuit, is going bad or some part of it's electrical system,
or the wiring has some major problems,