There is several possible causes. The most probable cause is wrong charge. Many units have a low suction safety on the low pressure side of the compressor. There is often a high pressure swithch to guard against over pressure also on the high pressure side. If your unit has the condensing fan stop in mid cycle, the compressor has inherent motor contacts inside the compressor to help guard the compressor from overheating. I just recently had to replace several customers main contactor because the contactor contacts were severly burned and sometimes could pass current and sometimes could not. I also had a few customers whose condensing unit was so dirty that the compressor was overheating causing the inherent motor contacts to open. Hope this gives you some ideas to look.
Answers & Comments
There is several possible causes. The most probable cause is wrong charge. Many units have a low suction safety on the low pressure side of the compressor. There is often a high pressure swithch to guard against over pressure also on the high pressure side. If your unit has the condensing fan stop in mid cycle, the compressor has inherent motor contacts inside the compressor to help guard the compressor from overheating. I just recently had to replace several customers main contactor because the contactor contacts were severly burned and sometimes could pass current and sometimes could not. I also had a few customers whose condensing unit was so dirty that the compressor was overheating causing the inherent motor contacts to open. Hope this gives you some ideas to look.