Your fan motor has 3 wires just like the compressor (single phase). If the run and start wires are reversed on the capacitor then the rotation will be reversed.

 

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Further info:

motor is 460, single phase.

The tech today tried reversing the start and run wires on the capacitor with no change in rotation. He once again moved the wires to another fan and this time, the problem did NOT move with the wires.

I am beginning to think there is a gremlin in the machine.

 

the fan may not have the right power at all, and may only be giving the illusion of running backwards. think about this, and see how you could prove that this statement does not apply.

 

Well, as I said, I'm a new apprentice...you lost me at "giving the illusion of running backwards." It's definitely running backwards...sucking air instead of blowing.

Are you trying to say that if the motor is under-voltage, it'll run backwards?

 

I have had this problem 2 times so far. Not saying that your answer will match mine cause it may not. So you should check into it more. I found that the motor was bad and the winding was so burned out that it made the motor spin the opposite direction. Everything was wired up right I went over it 3 times. I replaced the condenser motor and wired it the same way and it spun the right way after install. Again not giving you the answer this was just my situation only.

 

If you're double certain its wired correctly and has a good run cap, throw a new motor in and be done with it.

 

I agree with chuck. New one.!

 

The motor will surely be replaced, but I'd like to know what might cause this for my own knowledge.

Thanks for all the replies!

 

The motor will surely be replaced, but I'd like to know what might cause this for my own knowledge.

Thanks for all the replies!

For motors with no reversing plug: IF the motor has a good cap and is connected properly, the only remaining reason it will turn in the wrong direction is a problem with the wiring or windings within the motor.

 

single phase will not run backwards only 3 phase can. if the rpm's look about right, correct the problem with a new fan blade thats meant for the rotation... a little cheaper than a new motor andless work. often most motors the rotation is if you were looking at the butt end of the motor unless it says cwse or ccse that woull be shaft end of the motor. I have run into motors spinning backward such as 9w motors in supermarket evaps, usually can be corrcted by clipping the capacitor wire (which is usually blue) and just having the 120 going to the motors.

 

single phase will not run backwards only 3 phase can. if the rpm's look about right, correct the problem with a new fan blade thats meant for the rotation... a little cheaper than a new motor andless work. often most motors the rotation is if you were looking at the butt end of the motor unless it says cwse or ccse that woull be shaft end of the motor. I have run into motors spinning backward such as 9w motors in supermarket evaps, usually can be corrcted by clipping the capacitor wire (which is usually blue) and just having the 120 going to the motors.

not entirely true. I was cleaning coils the other day, restarted the condenser and the fan started running backwards, slow start as if it had a bad capacitior, but definatley backwards. I turned it off and back on again and it corrected itself. PSC Motor

 

I couldn't tell you exactly what happened inside your motor but it aint no good no more.
I have seen this alot on the Florida Heat Pumps in one building I work on they are 460 3 phase units that split out 2 legs and run a 460 split phase blower when these burn out they frquently run backwards. Chang the motor and move on.