Usually a faulty startup capacitor.
number of things. you could have a bad condenser fan motor. bad contactor or a bad run cap for the condenser fan motor.
The condenser fan is more likely to run when the car is idling. So if it NEVER comes on when idling you definitely have a problem. If the condenser is not cooled, then your compressor could get overloaded. It may be a problem with a relay that is preventing the fan from running - or some other issue.
If the defrost is on, the ac will be on, and the condsensor fan will be on.
Possibly a stuck contactor. It is the condenser fan outside the house.
Are you sure it is the condenser fan that continues to run? It is not uncommon for the radiator cooling system fan to continue to operate after you shut down, due to the fact that the coolant in the radiator is still hot. It is designed this way. Check to make sure you are referring to the correct fan.
Check the run capacitor, if defective, can cause the fan motor to run hot and stops till cools off, on n off. And the sound is a little different while running, it is hard on the motor.
No, most alternators with charge in either direction,, external fan type alternators may not cool as well when run in reverse, but you can find a bi-rotational fan.
Dirty condenser coil, high ambient temperature, problem with condenser fan, overcharge, non condensibles, high indoor load are the first places I would look. In that order.
It will run continuously if the refrigerant charge is off. The compressor, condenser fan and inside blower fan should all run at the same time. If your thermostat shows that the unit will not keep up, it will not stop. If the unit used to cycle ok, clean outside coil, change filter inside and put a thermometer on the register closest to the air handler. It should be around 52-60 degrees F.
The compressor continues to run after the condenser fan shuts off because it needs to maintain the pressure and temperature of the refrigerant in the system. If the compressor stops running, it can lead to an increase in pressure that could potentially damage the system.
Without an AC condenser, yes. I advise disconnecting the AC compressor so it won't run dry on lubricant.