If the system is cycling such as this, the unit is low on refrigerant. Turn off the unit so it does not burn out the compressor and have the system checked for a leak. There are pressure switches that prevent the system from running when the suction pressure gets to low. When your low on refrigerant and the system turns on the pressure goes even lower for just long enough to turn the unit off. As soon as its off the pressure equalizes and goes back up enough to cycle on then off again. This short cycle can destroy the compressor if its allowed to go on for to long.