"Bobo" wrote in message
...
On Fri, 13 Jul 2007 23:38:13 GMT, "Mike Dobony"
wrote:


"Telstra" wrote in message
...

"Bobo" wrote in message
...
What's up with a third horse whole house fan motor that has begun to
occasionally run backwards. This started happening about the same time
the switch went bad. I put in an identical switch and didn't mess with
the motor wiring. It's AC, 120.
Thanks

The Fan motor capacitor has two terminals each terminal connected
to a motor winding and one also connected to the Active. Switching
the Active to the other terminal will reverse the rotation of the motor


But how can this happen occasionally?


Googling I've found one reference to a motor running backwards
sometimes as the capacitor failed, I haven't found even one more
mention of this though,

I believe an intermittent or failing starting capacitor has been known to
cause intermittent reverse starting of lightly loaded motors. There seems to
be some validity to the theoretical explanation of how this can happen. I
would certainly try replacing the capacitor.

Don Young