# How do I slow down a fan motor?



## Daddy-O

First off let me appologize if this question has been posted before...

I have done a search and only could come up with ceiling fan motors. I have a small motor out of a small plug-in fan. It's one of the tall standing ones. It oscilates and rotates, but obviously rotates very fast. How can I slow this down? Any help would be appreciated, or a link to a past thread would help if there is one.

I'm new this whole haunting thing and electronics, so talk slow.

Thanks for your help...
Daddy-O


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## Doc Doom

I spent a whole lotta time and money trying to slow down a ceiling fan without success. I tried dimmer switches, fan speed controls, etc, and only managed a very slight reduction. I'm not an electronics guru but I think the ability is either in the motor or it isn't. I finall gave up.


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## HomeyDaClown

Most of those type fans use shaded pole single-phase induction motors.

You need to look for a speed control that uses a Triac to control the speed on them. Also you might want to run some tests and see how much heat is generated by the motor. Oscillating fans beat the heat by blowing air over the motor core as they work. If left uncooled, they can easily over-heat and burn up.

Something like this:




Cieling fan motors are usually modified 3-phase induction motors that have a capacitor start.


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## fritz42_male

A better way of approaching this might be if you give us an idea of what kind of prop you want to make.


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## corey872

Some good info posted. Doc pretty much summed it up - the ability for speed control is basically built into the motor. Ceiling fans and some other small fans sometimes use a capacitor to vary speed. You might be able to vary the value of the capacitor to change speed a little. But the downside of fan motors is they have practically zero start-up torque and very little running torque. Then you usually loose some of that torque if you attempt to run at a lower speed.

So overall, using a fan motor to run anything mechanical usually doesn't work out too well. For a small prop, a small motor with a gearbox can get you down to a slow speed and boost the torque. DC permanent magnet motor (ie windshield wiper motor) with a PWM speed control driver can give you nearly full torque across a speed range of ~5 to 95% (and be completely variable speed as needed)


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## Daddy-O

Thank you for your replies. I was going to use the spinning motor for a grave jumper or something along those lines and the oscillating motor, I'll probably stick a foam head on it and attach it to a torso and let it look back and forth on my porch. This isn't a ceiling fan motor, just a small stand-alone fan.


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## fritz42_male

I'd be careful of using an oscillating fan as a prop. The motors are designed to be cooled by the fan.

Better to find a deer motor or windscreen wiper motor and knock up a suitable link system.


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## Daddy-O

Thanks Fritz, that's good info I didn't know. I've been looking at Monsterguts at their wiper motor and controler, however they are currently out of stock on the Pacemaker. I guess I'll wait patiently


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## Stinky Pete

Lots of motors here...

http://www.sciplus.com/category.cfm/subsection/18


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## Screaming Demons

I have always found American Science and Surplus to be too expensive for things like motors. Surplus Center has much better deals.


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## Jaybo

Daddy-O said:


> Thanks Fritz, that's good info I didn't know. I've been looking at Monsterguts at their wiper motor and controler, however they are currently out of stock on the Pacemaker. I guess I'll wait patiently


Well, if you are looking at the Pacemaker, then you might want to also check out the PicoVolt from FrightProps. It costs about the same amount and has a lot more features and a smaller size that can be hidden inside of a prop.


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## Daddy-O

Awesome Jaybo. This is exactly what I've been looking for. Thanks!


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