Can i slow down a desk fan?

[Jack.Straw]

I am doing a fan/wind related art installation for a party and want to turn a couple box or desk fans into disco lighting for the dance floor. The idea is to glue bits of mirror to the fan blades and hit them with a couple MR11 bubs. I'd like to slow down the blades to "disco speed". I'd also like to do it for as little money as possible, as it is a very temporary installation. I work for a lighting and electrical distributor and have access to lighting control brands such as Lutron and Lightolier at wholesale cost if using such a dimmer/rheostat device would be the easiest way. I am also quite comfortable with electricity and wiring. Any advice you can offer would be greatly appreciated. Thanks! -Scott

 

[BradtheRad]

You probably want 1 rotation every few seconds.

You can try a dimmer but it will take a special kind that reduces power to just a few percent.

Or maybe a ceiling fan motor? It's made to run at a slower speed (inefficiently, on purpose). Expensive however.

Consider a motor of the type that drives an old-style clock or timer. It has internal gears to make the output gear turn slowly.

 

[kak111]

Windscreen wiper motors are strong and slow running motors.
Easy to control and cheap when find in scrap yard or surplus.

Using a wiper motor in your projects....

**broken link removed**

 

[KJ6EAD]

Most inexpensive fans use shaded pole motors. There are speed controllers available. Just search online.

Another possibility would be to use a geared shaded pole motor such as a barbecue spit rotor or similar slow turning device to rotate your mirrored panels.

Disco speed = 140 beats per minute?

 

[Jack.Straw]

Thanks for the responses guys! I'm using a 2.1 amp box fan with 3 speeds. I read online that it may not be possible to slow down fans of this type? My solution, and only because this is a very temporary installation, was to use a relay controlled by a PIC to turn the fan on and off at timed intervals. Basically, it allows power through for about 1 second, just long enough to start the motor moving. Then there is a no-power pause for about 6 seconds while the blades slow down to a stop. This results in varying speed disco lighting. It's an ugly and dirty way of accomplishing my goal, and it can't be good for that fan motor.. but eh, it works... for now