ceiling fan spins slow in reverse with switch off

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FREEBALL

Senior Member
Location
york pa usa
Customer has an issue w/ a lutron 3 speed fan control with a built in dimmer for lights. The fan starts to spin real slow in reverse with the switch supposedly off. I say that because if you use some force to the switch it does stop the fan so the switch must be bad. So why does the fan turn in reverse, any ideas? I was thinking something to do with the low voltage that is leaking through the switch since it is not completely off or open.
 

kwired

Electron manager
Location
NE Nebraska
If this is a typical ceiling fan with reversing switch on the fan itself there is no way it will "run" in reverse without the reversing switch being operated, bypassed etc. To reverse this type of motor you need to reverse input power polarity on either the main motor winding or the aux motor winding.

You sure there is not just some air current in the room that is pushing the fan in reverse when it is stopped? What does it do if you turn off power at the breaker to ensure there is no suspected current leakage and/or can you measure any leakage voltage or current when the control is off?
 

FREEBALL

Senior Member
Location
york pa usa
Kwired,
Im going over tomorrow I have beaten the web on this and really came down to possible air flow or rf interference. Now they state they don't use a remote for the fan but that does not mean it isn't remote ready, so Im going to look at it. I was thinking leakage also maybe coupling, if you may, in the 3 wire that feeds the fan control/dimmer but even so what would make it turn in reverse. Im gonna figure this out hopefully anymore insight would be appreciated. But a lot I read was RF issues and this fan is less than 2 years old and is a hunter douglas so its probably remote capable. So this may be my issue, unsure:?
 

kwired

Electron manager
Location
NE Nebraska
Kwired,
Im going over tomorrow I have beaten the web on this and really came down to possible air flow or rf interference. Now they state they don't use a remote for the fan but that does not mean it isn't remote ready, so Im going to look at it. I was thinking leakage also maybe coupling, if you may, in the 3 wire that feeds the fan control/dimmer but even so what would make it turn in reverse. Im gonna figure this out hopefully anymore insight would be appreciated. But a lot I read was RF issues and this fan is less than 2 years old and is a hunter douglas so its probably remote capable. So this may be my issue, unsure:?
I think the capacitive coupling theory is unlikely to be able to provide enough power to move the blades, and even if it could provide enough power - one would need to operate the reversing switch before it would move them in the other direction.

I am all that familiar with some of the latest in advanced units that may be out there, but reversing switch would need to be controlled electronically for this unit to have any chance of running backward because of leakage induced or coupled current, otherwise a manual reversing switch will not change state unless it is manually operated and the polarity relationship of the motor windings will not change to cause it to reverse.
 

ggunn

PE (Electrical), NABCEP certified
Location
Austin, TX, USA
Occupation
Electrical Engineer - Photovoltaic Systems
If this is a typical ceiling fan with reversing switch on the fan itself there is no way it will "run" in reverse without the reversing switch being operated, bypassed etc. To reverse this type of motor you need to reverse input power polarity on either the main motor winding or the aux motor winding.

You sure there is not just some air current in the room that is pushing the fan in reverse when it is stopped? What does it do if you turn off power at the breaker to ensure there is no suspected current leakage and/or can you measure any leakage voltage or current when the control is off?

When you see this slow reverse movement, if you stop the fan manually can you feel the motor trying to push it against you?
 

FREEBALL

Senior Member
Location
york pa usa
Well it was the the heat/fan when it came on. They said it never did it before and that the ventilation couldn't be the cause and after using my paramedic skills, I asked if there were new electronics in use etc thinking of remote control, and the answer was no. So I started to fool with the thermostat making the heat come on and off and nothing. I reached up to use the chain and bumped the fan blade slightly with the heat on and it started to turn on its own and did not stop. I turned the heat off and the fan came to a stop. turn the heat on and it started to turn on its own. I did this a few times to satisfy the customer. Come to find out they moved an armoir in front of the heat vent recently which directed the heat straight up. And the fan was slightly unbalanced and wala theres the answer. Thanx for all the brain storming.
 
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