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Richard Daugird
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I have seen them on eBay for cheap, they look pretty cool. I wonder if a fan's operating speed could be controlled with one of these?

John McComas
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Nichrome power rheostats rated for more power than your fan uses could be used to control fan speed, but,
They need to be big and bulky and waste/generate heat in operation. 
I have a few, but I use them to determine the resistance needed to replace a burned out speed resistor.
I have a 100 ohm, 100 watt Ohmite power rheostat that I use to determine resistance for various speeds.


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David Allen
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nRichard Daugird wrote: I have seen them on eBay for cheap, they look pretty cool. I wonder if a fan's operating speed could be controlled with one of these?
Richard, as John says, using any rheostat to "directly" control the motor is going to require a massive one.  Most of the slide ones I've seen on eBay are low power devices. They are made for signal control, such as audio levels.

While these can not directly control the fan's motor, you COULD use one of them to control a TRIAC or other solid state speed control device.... assuming your motor is compatible with it.

Steve Stephens
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The best way to control speed of a fan is by using a Variac.  Good old ones from the 1960s-80s and US made can be had for under $100, often for $25, more or less, at radio swap meets, etc.   I run fans from 120 volts down to less than 6 volt battery DC fans using my variac and, when needed for DC, a bridge rectifier, about $5 or less and readily available and tiny.

David Allen
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Steve Stephens wrote: The best way to control speed of a fan is by using a Variac.  Good old ones from the 1960s-80s and US made can be had for under $100, often for $25, more or less, at radio swap meets, etc.   I run fans from 120 volts down to less than 6 volt battery DC fans using my variac and, when needed for DC, a bridge rectifier, about $5 or less and readily available and tiny.
Yes this is true; however I was thinking he wanted something small which could be installed permanently on a fan. But yes the variac is the way to go, with its undistorted AC waveform and full variability.


George Durbin
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Ordered this from China or Taiwan or some where over there... $19 shipped... it appears it should work well to run DC fans... Lots of stuff like this available cheaply... I am going to order one to get me to 110dc too... I will check this one first and give a report later...
Geo...

George Durbin
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:D :D :D

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Russ Huber
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David Allen wrote: Richard Daugird wrote: I have seen them on eBay for cheap, they look pretty cool. I wonder if a fan's operating speed could be controlled with one of these?
Richard, as John says, using any rheostat to "directly" control the motor is going to require a massive one.  Most of the slide ones I've seen on eBay are low power devices. They are made for signal control, such as audio levels.

While these can not directly control the fan's motor, you COULD use one of them to control a TRIAC or other solid state speed control device.... assuming your motor is compatible with it.

Earl Ballentine(Russell Electric Co.)  and Robert Devore(Fresh'nd-aire Co.) it appears used CENTRAL RADIO LABORATORY(CENTRALAB) radio related rheostats for speed control in their EARLY BALLENTINE MOTOR models 14, 16, 18, 20, 22, .......+? Central Radio Laboratory was incorporated and located in Milwaukee, WI. in 1922. The early 1920s  saw a huge boom in home radios.  Signal Electric Co. of Menominee jumped all over that one to help get them on the map after big daddio Henry Tideman took off to Cairo with over 2/3s of the Menominee concern.   








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Last edited on Thu Dec 7th, 2017 06:07 pm by Russ Huber

Don Tener
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My small Canadian made 16-C Vornado uses one also. I like how you can smoothly dial the speed with it.






Richard Daugird
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David Allen wrote:Yes this is true; however I was thinking he wanted something small which could be installed permanently on a fan. But yes the variac is the way to go, with its undistorted AC waveform and full variability.


David is correct, I am planning a custom pedestal fan and was thinking a slide would look good on there. I have several Variacs, they work great.

David Allen
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Richard Daugird wrote: David Allen wrote:Yes this is true; however I was thinking he wanted something small which could be installed permanently on a fan. But yes the variac is the way to go, with its undistorted AC waveform and full variability.


David is correct, I am planning a custom pedestal fan and was thinking a slide would look good on there. I have several Variacs, they work great.

Here is a picture of a control made from a slide pot. It was taken from a car radio Bass / Treble control and re-purposed for a fan speed control. The body of the control is an old industrial circuit breaker handle mechanism.The radio is another similar model to what I used for parts. One of the slide pots is sitting against the radio lower knob at the left. The other is mounted on the handle mechanism.




Asembled panel, from the rear.


From the outside:



George Durbin
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This speed control all the way from China for $1.76 shipped no charge to your front door... works well on those vornados... The 25amp thing kinda makes me wonder a little bit...
Geo...

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Last edited on Fri Dec 8th, 2017 02:24 pm by George Durbin

Richard Daugird
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I saw that control on the Ilg project😁.

George I got a handful of those little controllers haven’t tried them yet. 25 amp made me wonder as well. Those 15&20 amp Variacs are about 20 lbs...

George Durbin
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I have a couple nice old variacs... These seem to work pretty good...
Geo...

Richard Daugird
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When I learned about Variacs, a bought several. Or a dozen or so...need to make some nice wood boxes to mount them in.


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