I have a small three speed fan currently connected to a smart plug. What I would like is to control 4 states - off, low, med, high. Anyone know of any hacks for this?
This has been discussed before, but to some it up, it depends on the fan. If it has an IR remote you can control it that way. If not you will not be able to control speed with a smart plug, unless the smart plug has dimming capability. If it does, you can try setting the fan on high and then adjusting your dimmer settings to 0% 33% 66% 100%. Depending on how the fan it designed this may, or may not give you the desired results. If you smart plug does not support dimming and the fan is not IR, I don't think l you can automate it other than setting it on high and use off/on.
I'll be watching to see if I am proven wrong again (happens more here than most places and I kinda like it)
Using a dimmer to control a motor is a fire hazzard.
If you took a paper clip and stuck it in the wall, you wouldn't be surprised at the flash, the pop, and the heat. It's a dead short. No surprise. Think about buying 100 ft spool of single strand wire from Home Depot. Strip off each end and imagine sticking it into the wall socket. Flash, pop, heat a little smaller scale because of the resistance of 100ft vs 2" of paper clip.
Motors are coils of wire. Dead short.. til the magnetic field builds, then they are inductors. When the magnetic field collapses, there is an inductive 'kick' and that will eventually burn out circuits not intended for inductors.
Read the label on the dimmer before you buy.. if it says, "not for inductive load" it means it.
Three speed fans like that typically use different sets of windings for each speed. So one way to get this done would be to use a dry-contact corresponding to each speed to energize the winding. And then some sort of automation to ensure that only one dry contact is energized at a particular time.
I was thinking maybe a three way relay device of some type....
The Zooz Zen16 has 3 dry contacts in one unit. I have a few and they work great. Not sure how you would wire them for this application.
@aaiyar are you talking about opening the fan and making those connections at the switch/motor?
There are multiple channel arduino relays. Maybe time for a Hubduino project?
At the switch (easier)
Just use this
I think that switch is made for a ceiling fan, which I don't believe is the same as a pedestal fan.
Ceiling fans use capacitors to control speed, and I don't think most pedestal fans use that same method . I could be wrong as I'm going based on disassembly recollection
Small fan motors are usually "shaded pole" motors where the motor coil is tapped at three points to obtain 3 speeds. Each switch position connects the incoming AC a different number of coil turns, one for for each speed selected. Powering different taps of the motor results in different torque (fewer turns = more torque, more turns = less torque).
There is no reason a fan dimmer will not work with a shaded pole motor. You should however google shaded pole motors to see the copper turn on the laminations and compare it to your fan motor to be sure you have a shaded pole motor.
BTW the difference between a normal dimmer and a fan dimmer has to do with how the current lags the voltage during the AC cycle. This effects the way the output semiconductors need to be controlled.
I might be interested in doing this. How would I do the wiring with the line out from the fan dimmer?
Simply treat the fan as if it were a bulb connected to any dimmer, and leave it on high.
Not knowing your specific fan, you will notice most fan switches are "off, hi, med, low" so in theory you would go from off to hi, this gets the fan moving. I have two fans my wife uses for drying her jeans she won't put in the dryer. These are left on low and plugged in, never had an issue.
However if you want you could tell the dimmer to start at something north or 80% then change to the desired level.
Also the fans don't work too well at very low speeds. I would recommend you don't go below the current low speed (estimated).
You are absolute correct for some motors. Induction motors especially should not be "dimmed". However small shaded pole or universal motors can be dimmed with no issues. I would however not go to very low speeds.
The "inductive kick' is certainly and issue with DC motors (brush type) but not so much on AC as the flux builds and collapses 120 times a second. Still you are correct that you dimmer should be rated for fans.
Ok any recommendations on a fan comparable dimmer outlet?