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How can I slow down or adjust the speed of a 230v 17w desk fan? Answered



you did say this was a 17 watt 230V desk fan, right? In other words, UK single phase? At a guess, a 6-7 " dia fan?

lol some of the answers are a bit on the paranoid side of the house, almost as if they didn't read the question or aren't sure what Watt means. This desk fan is little more than an AC version of a computer fan, and can be run from 0 to full speed with little or no concern. IMPE, the scr and pot were left out so it cost less.

BTW, if you've been put off the idea by the alarmist reply, just add a small lamp to the enclosure containing the dimmer, so that when it's turned on you know it.


8 years ago

Some light dimmers will not work well with inductive loads as the trigger angle can be upset by the nature of the motors inductance. I would suggest possibly a series lamp (Lemonies Idea) As Steve has mentioned the motor may need a 'KICK' to start but once running can then be limited. How about experimenting with a PTC resistor _ low resistance cold, resistance increase as PTC warms up. I'm sure many years ago I can remembering experimenting using a high value/high voltage capacitor (similar to a light fitting choke/capacitor start circuit) in series with the motor alters the lead/lag voltage to phase angle! Again worth trying ... have fun.

Be a bit careful with some of these suggestions. If its an AC motor, which I think it must be, then mains motors like this won't stand much modulation of speed, and they may struggle to start (and burn out) if you try and start them in their slow speed running. Steve

Run it in series with an incandescent light bulb. Changing the wattage of the light bulb will adjust the speed. L


8 years ago

does it have any speed control on it? digital or mechanical If there is no speed control or it is mechanical here are two options 1. open up the fan and place a 5watt potentiometer or variable resistor on the positive wire leading to the motor 2. use a dimmer switch at the plug if you can not find one with the right plug type find one with a max voltage of 250 or better and not with a digital control system any have a better idea? please post it

I think the dimmer is the best solution you suggested. and would have done so myself if you hadn't already beat me to the punch.

I was going to try 2 or 3 ceramic resistors tapped to the fan supply with a rotary switch, but the ceramic resistors will get hot , is there any more ideas ther is no speed control of any kind with the fan.

I would like to know this, too, as my fan - on its slowest setting - is too fast! lol!