John Boyd, it could possibly be the compressor is locked up. This inverter makes diagnosing the compressor a bit more difficult due to the inverter mounted on the side of the compressor. The thermal overload is what’s cutting off the compressor. It’s job is to cut off the compressor if it’s too hot or pulling too many amps. If you had an amp meter or a two splitter you could check the amp draw at the moment it’s trying to come on. If the amps are higher than whats on the data plate than the problem is in the compressor. The compressor has to be replaced by a certified hvac/refrigeration technician per the EPA guidelines. The cost for this repair is much higher.