How can I avoid killing portable fans using a GE Fan controller?

Thread Starter

enishoca

Joined Sep 18, 2019
3
Installed a Z-Wave GE/Jasco Fan controller in a box and had it control an outlet and plugged a portable fan in the outlet. Basically wanted to have speed control over the portable fan in my home automation app.

So far I have killed two fans, one was an expensive Vornado the second one was a cheap Honeywell. Both were 3-speed fans, with a mechanical switch for selecting the speed (low, med, high);

It took almost a year for each of the fans to die. At first they would take longer and longer to start-up and then they eventually stopped working. And once the symptoms developed they behaviour was same whether connected through the GE fan controller or directly in wall.

BTW I have 3 other switches controlling ceiling fans and they have been going great for 3+ years.

Anyway now that I have learnt this expensive lesson - wondering if there is someone here who has an Electrical Engineering background who can explain:

  1. Why did those fans stopped working? i.e. why was I wrong to use the controller, (really looking for a hard-core EE explanation, not because “it says so on the box.”)
  2. is there something that can be done to fix them?
  3. Is there a way to internally rewire an off the shelf multi-speed portable fan so it behaves like a ceiling fan from an electrical perspective and use these controllers>
Thanks in advance.
PS - I hope this question is within the scope of this site, in most HA sites you don't have many EEs hanging out, if it is not apologies in advance as well as if someone can point to a better venue to raise this question in.
 

Thread Starter

enishoca

Joined Sep 18, 2019
3
What mechanical speed setting did you use when operating the portable fans?
I used the highest setting - at-least I started there.
It is possible that someone else in my house-hold may have modified it for short periods of time, but generally it was set on high and left alone and we used the app to control the fan.
 

Thread Starter

enishoca

Joined Sep 18, 2019
3
Perhaps that's harder on the fan motor, if you are greatly reducing its speed.
For that it might be better to operate at the lowest speed that you need for the maximum (or is the maximum you want, the highest speed?).
That doesn't really jive. Why would that be any different than when the fan is plugged in directly? The fans are designed for normal operation that way, it's not that controller can make it go faster?

Was really hoping for someone who know what these controllers do to the electric signal and why they work on ceiling fans and not portable fans. There must be something different on how the ceiling fan motors are vs portable fans.
 

crutschow

Joined Mar 14, 2008
25,129
Why would that be any different than when the fan is plugged in directly?
When the fan is plugged in directly, you are just switching windings with the manual switch to change the speed.
The dimmer reduces the voltage, often using a SCR chopper which changes the waveshape, adding harmonics to the power.
This can cause increased eddy currents and power loss in the motor, causing overheating.
If you start out with the fan at a slower speed, you will need to reduce the voltage less, thus distorting the waveform less.

Have you noticed whether the motor gets warmer when you use the dimmer.

Ceiling fans are designed to operate safely with the distorted waveshape.
Standard fans are not.
 

Reloadron

Joined Jan 15, 2015
5,509
I can only offer some of what I have seen over the years. I would venture a guess and that is about as good as it gets, a guess. Depending on who builds the fan, a portable fan in this case, those which already have speed control like Low, Medium and High use different methods in the electronics to change the fan motor speed. I see crutschow has just posted where I was heading with this. Simply put the fan motor needs to be compatible with the method used to control the speed. The dimmer type controllers, which are likely the most common and popular will work fine with some portable fans but with others will cause overheating and subsequent failure of the motor. Without getting any deeper into the motor I believe crutschow likely has the problem identified. The controller is not compatible with the portable fan motor.

Ron
 

MaxHeadRoom

Joined Jul 18, 2013
20,918
I agree that those controllers are probably only suitable for one-speed fans. the 3 speed variety are not designed for such.
Another thing to check, is if they have a run capacitor and is of Chinese origin, these are often a cause of failure of these style fans.
If so, replace with other manuf. sources.
Max.
 
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