Dimmer switches & fans

[Arthur 51]

Hi all. If a suitable dimmer switch is added between the desk fan and wall socket would it provide 'infinitely' variable fan speeds?

And if possible what components should I use?

Thanks. Arthur

[meow2222]

A fan is an inductive load, and lamp dimmers arent usually up to inductive loads.

Otherwise yes, down to a point. If you run the fan too slow it risks stalling ans frying.

to do what, make a dimmer?

NT

[Arthur 51]

Thanks.

To make a desk fan that includes dial/button that will provide variable fan speed.

Arthur

[Arthur2]

Srry. Re-reading yur question... A lamp dimmer switch seems unsuitable from yur description so is there another component type I could use?

Arthur

[Chip]

On Wed, 30 Apr 2008 05:06:48 -0700 (PDT),it is alleged that Arthur 51 spake thusly in uk.d-i-y:

Hi Arthur, a word of warning here, the output from a dimmer is far from a sinewave, it's [to be non technical] all spiky and has sharp edges! I am not sure how this would affect a table/desk fan, but on a ceiling fan I once connected to a dimmer (temporarily until I could get a matching normal light switch) it buzzed so horribly even at max. speed that I had to ask the householder to promise to only use the light part till the switch turned up.

[Dave Plowman (News)]

A dimmer suitable for an inductive load should work after a fashion. So one suitable for low voltage lighting where a true transformer is used should be ok.

If you're handy with a soldering iron Maplin etc do kits for motor speed control. A Google should also find something.

[AJH]

I bought one of these Vellermann kits when Mr Plowman recommended it years ago, to control the motor in an Earlex vacuum used as a blower, it worked well apart from needing a new thyristor and a bit of track shorted. It does control a small induction motor but only by increasing the lag, which I suspect means there are larger heat losses somewhere.

AJH

[Dave Plowman (News)]

Was the heatsink/cooling adequate? I've used one of these for many a year

- at one time it controlled the speed of a drill in a stand, but now is just used wherever needed. But even with a universal motor it doesn't work too well at very low speeds.