Electrical Questions? Ask an Electrician Online.
Good Morning. Welcome to Just Answer.
A bad starting capacitor is a definite possibility in causing the compressor to trip the breaker. The good thing about capacitors is that they are generally pretty inexpensive, and not usually extremely difficult to replace.
That being the case, it's worth a shot to replace it, to see if that corrects the problem.
Also, I have a portable compressor that did the same thing several years ago. Mine was essentially brand new when it happened.
I don't know how it happened, but mine was very low on oil, which caused it to get very hot and trip the breaker.
Oddly, it was shipped filled with oil to the proper level, and it never has leaked any oil. So it's a mystery to me where the original oil went. If yours uses oil, you may want to verify that it's at the proper level.