Sounds to me that you have a circuit on the unit creating a high resistance, causing the circuit breaker to trip. This can be caused by many things, dirty or bad grounds, wires corroding, switches corroding, wires intermittently opening or shorting, etc. This type of electrical troubleshooting is one where a technician needs experience and patience to solve. If it came to me with this problem, I would start by checking every connection I could find, making sure each one was clean, dry and tight. Next I would run the unit until the problem occurred and then use my nose and fingers to find wires or components which are hot and overheating. Tools I would have on hand. A assistant, wire brush, small file, spray contact cleaner, air supply, dialectic grease, and a truck load of patience. I used to run into a problem like this about once a year, when I was working full time, and have had to bill customers anywhere from thirty minutes to (YES) eight hours. I’ve attached the parts manual which contains a schematic for your unit which should help you in your adventure. Good Luck and post back if you have any questions. If you don’t feel comfortable tacking this job, I recommend finding the oldest mechanic in your area, who understands your problem, may have to get out of your local. The younger guys most often only understand basic repairs or plug and play systems.
https://www.thepowerportal.com/ipls/ipl.htm?md=2691673-00~_IPLURL_LO.pdf