I arrived for a recall on a system I recently repaired. I found the new contactor to have been welded closed over night. I pulled the contacts loose and I turned the system on and off multiple times to see if it would stick again. I explained to the homeowner I can put a new one in but with the power problems you are having I expect this to continue regardless of installing new contactors. I explained that we can add a hard start kit and that may help lower the ark across the contactor when the system cycles on. Tho if the system is having a power surge or on and off issues it can cause problems with the system regardless of the system having new parts. I let this one call be under warranty but if we continue to have to come out because of the power issues that will void the warranty because that is more than likely the problem that is causing the parts to fail.