RV Repair: compressor on roof ac unit, ac unit, extension cord

Question
We have just purchaced an older model camper.  We have it powered by an extension cord running to our house. When we turn the a/c on cool, the compressor kicks on for a couple of seconds and just when the air starts getting cool it goes off.  The fan is blowing fine but the compressor will not stay on.  The compressor will kick on and off every few minutes. We have added freon.  What do you think?

Answer
Hi Stacy:

You have several issues that need addressing. First off, I will need the model number of the air conditioner, so I can determine the capacity of it. Most of the A/C units will not run off of an extension cord, as they pull too much current. What size is the cord, and what is the length of cord? That most likely is why the compressor is cutting off on the internal electrical overload, due to low voltage. Another comment you stated is that refrigerant was added to the air conditioner. Why was this added. Was the system out of refrigerant, or was it because it was cutting in and out? Was the unit cutting in and out before the refrigerant was added? I will be awaiting your reply. I will be happy to assist you any way I can.

Regards, Larry