Car radiator fan?

GHA

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ISTR a while ago reading a tip about using a 24v truck fan down below running slower on 12v for a quiet fan which could push a load of air. Prob up a scrapyard monday so might grab one for a play, maybe a 12v & control the current or voltage to slow it down. Though a very quick glance on google PWM control was mentioned - that how they work these days? Either way speed control isn't a big deal. Coframos are OK but not that powerful and not really that quiet.

So has anyone actually tried this?

(For hot places, not the 'a bit warm couple days a year' UK ;) )
 
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matthewriches

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I've tried this with an old Land Rover I had. If it is a permanent magnet motor with no control or protection gubbins inside the fan then it should spin slower at 12v instead of 24v. Any with any form of circuitry normally don't do nothing or just hum.

PWM controllers essentially turn on and off to regulate the speed (or brightness in the case of LED for example). I'm sure Google will tell you more.

Make sure you have a PWM that is "big enough" if you go down that route as if too small, bits can melt on the board or fuses start to blow!
 

GHA

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I've tried this with an old Land Rover I had. If it is a permanent magnet motor with no control or protection gubbins inside the fan then it should spin slower at 12v instead of 24v. Any with any form of circuitry normally don't do nothing or just hum.

PWM controllers essentially turn on and off to regulate the speed (or brightness in the case of LED for example). I'm sure Google will tell you more.

Make sure you have a PWM that is "big enough" if you go down that route as if too small, bits can melt on the board or fuses start to blow!
Ta. Not a huge fan (;0 ) of PWM onboard, pain to get rid of the noise on RF. Maybe constant current & 2 wire. Anyway, control is sortable one way or another, interested in how much air they move and how noisy.
 

lw395

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I believe the radiator fan motor on my bike is electronically commutated, like a PC fan motor.
That possibly isn't going to enjoy either PWM or a low supply voltage.
There are a lot of brushless DC motors around these days.

Some motor control PWM is at quite low frequencies, like audio, so RF interference less of an issue.
 
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