Dimmer at ceiling fan controller?


(Chrisb) #1

As I’ve been doing various research about z-wave switches I noticed that some of the dimmers out there talked about being able to use them as fan controllers. It got me to thinking, could this be a viable option?

Theoretically it should work: Turn the fan on full and then just use the rheostat in the dimmer to control the amount of energy going to the fan which should control the speed of the fan.

But what I have no clue on is what this will do to the fan motor. Is a ceiling fan motor able to handle variable energy pushed to it or would this cause a burn out of the motor?


(Solardave1) #2

I personally have ruined a perfectly good ceiling fan motor doing this. I don’t know why, I never bothered to investigate why, I just know I had to buy a new fan. You’d think it should work. There are fans with rfremote key fob remotes that I’m sure could be hacked for ZigBee control - most likely with the dim level command (ha stack).


(Chrisb) #3

That’s kinda what I was afraid of. Guess I won’t experiment. The wife has been pretty supportive and even kinda likes some of the things that SmartThings has brought to our house. But if I start cutting into walls to add switch boxes and start burning out fan motors… that’s not going to go over so well.


(Sjstone) #4

The danger of using a dimmer as a ceiling fan control is the amount of current flowing through the switch to the motor. Motors require a high amount of current to get the motor moving. Your switch has to be able to handle the in rush of current or else it could potentially cause a fire if it happened to overheat. The current going into the motor is slowed by a starting capacitor which will momentarily stop and start current until the motor reaches about 3/4 its operating speed.

Wall mounted speed control switches contain either solid state circuits or capacitors that can control the mount of current going to the fan field of the fan wiring. These are designed for motor control rather than lighting control.

Also, you would need to make sure your fan is already wired for a switch. Some people do it and don’t have any problems but I personally wouldn’t risk it.


3 prong plug that dims
(Chrisb) #5

Yeah… looking like a no go. :frowning:

My ceiling fans in my bedroom all have separate lines running from the switch to the unit for the fan and for the lights, so it’d easy enough to put another wall switch on the fan line. Of course I’d have to cut into the wall to add another spot for a box… which would be a lot harder. And then if I can’t control the speed (only on off), then it sorta defeats the purpose as I’d have to pull the chain anyway to adjust speed.

Now, on a somewhat related note: I have an attic fan that is currently connected to a timer dial. Twist the dial and the fan comes on. After however many minutes/hours your turned the dial it shuts off. Would there be any problem with replacing this dial with an ON/OFF (NOT a dimmer!) switch? Again we’re probably talking a larger load of power than the average ceiling light, but it’s just normal house current. I suppose I need to find out the Watts that the fan is pulling and see if that exceeds the limit of the switch.


(Solardave1) #6

You can certainly swap the timer out for a standard switch as long as its <15 amps which most attic fans are. Put a z-wave temp sensor in the attic and you can automate the whole thing.

(That one was easy)