Under normal circumstances, your AC unit should kick on for a little while, turn off again, and then kick on again when the room warms up and needs more cooling. This should happen only a few times per hour. If the air is switching on and off every few minutes, this is an issue. Your home won't cool properly, and the constant on-and-off switching will wear down the unit prematurely. Known as short-cycling, this AC behavior can indicate a number of problems. Some of these issues can be fixed with some basic DIY know-how. Others will require you to call an HVAC professional.
A very dirty filter
The more dust that accumulates in your AC filter, the harder the unit has to work to force air through that filter. If the filter is incredibly dirty, your AC unit may have to work so hard to push air through it that it's overheating. When it overheats, it switches itself off. Once it cools off a bit, the thermostat triggers it to come on again, but it only cools for a few minutes before it overheats again.
AC filters only cost a few dollars, so replacing yours is a good first step to take. Usually, the filter is found in a slot between the blower and the large air return duct. Pull on the cardboard edge of the filter to remove it from the unit. Then, push a new filter (make sure you buy the same size) into the space. Turn the thermostat down to trigger the AC to kick on, and see if you've solved the problem.
The outdoor condenser is blocked
If there are weeds growing up around the outdoor condenser unit, there may not be enough air circulating for it to work properly. Take a look at the area around the condenser, and if there are any dense weeds, bushes or grass, trim them away. If there are any leaves or debris in the condenser itself, you should remove the cage around it (use a screwdriver to remove the screws, and then lift the cage off). Use a shop vac to suck up any debris that's inside of it. Then, put the cage back on. With any luck, the increased air circulation will solve your problem.
The evaporator coils are frozen
This one should be pretty easy to spot. If the condenser coils are coated in an actual layer of ice, this is why your AC unit is short-cycling. You'll need to turn the AC off completely, and give it a chance t thaw out. Then, make sure the condensate tube (the clear tube leading from your AC unit to a drain) is not plugged. If you see any debris inside of it, place a wet-dry vac at its opening to suck the debris out. A blocked condensate tube may cause liquid to build up on the coil and freeze. When the unit is frozen, it's only able to operate for a few minutes at a time.
Also, hose down the coils using a regular garden hose. This will remove any dirt and debris, which may cause condensation to "stick" to the coils and freeze. Once you're done cleaning, turn the AC back on and see if it works. If it freezes over again, you'll need to call your HVAC repair specialist, as low refrigerant levels may be contributing to the freezing -- and a professional must top up the refrigerant because it's an involved and dangerous job.
If a dirty filter, frozen coils, and blocked condenser unit is not causing your AC to short-cycle, then get in touch with an HVAC company like Wright Total Indoor Comfort to discuss other possible causes -- like a faulty thermostat or improperly installed AC unit.