Computer fan wires

[clyst]

Hi all

I propose to employ a computer fan as a galley extraction fan . fan has 3 wires red, black and blue.

Correct me if im wrong conns are---- red Pos------black neg blue redundant ??

 

[Poignard]

Yes the blue is probably for a speed monitoring output

 

[st599]

Is the blue not the speed control?

 

[clyst]

Thanks chaps . Does that mean it will run at full speed if the blue is not connected ??

 

[Poignard]

st599 could be right, if it's a 2-speed fan. What does it say on the label?

 

[Cardo]

Many fans have quite fine speed control when connected to modern motherboards. The third wire as previously mentioned will be for the motherboard to know what speed it's spinning at. You can just ignore it and the fan will run at full tilt.

 

[clyst]

Many fans have quite fine speed control when connected to modern motherboards. The third wire as previously mentioned will be for the motherboard to know what speed it's spinning at. You can just ignore it and the fan will run at full tilt.

Cheers

 

[Searush]

Many fans have quite fine speed control when connected to modern motherboards. The third wire as previously mentioned will be for the motherboard to know what speed it's spinning at. You can just ignore it and the fan will run at full tilt.

Until it seizes or blows up in the damp salty atmosphere of a boat galley.

 

[VicMallows]

Until it seizes or blows up in the damp salty atmosphere of a boat galley.

I have several 12/24v computer fans on the boat and none have failed in over 10yrs. Mind you, the fans are at least 25yrs old, marked 'sample', and were intended for commercial computer use.

 

[CelebrityScandel]

Is the blue not the speed control?

Blue is speed control on a 4 wire fan.

On 3 wire fan the non black or red wire is almost certainly tachometer although colour is often other than blue.

 

[bignick]

I hope you're talking about one of the larger slow-spinning ones. The whine from the small 40-60mm ones would drive you nuts!

 

[theoldsalt]

Yes, a fan from an old PC would probably be noisy but most new fans are virtually noise free (from the bearings)

 

[macd]

I have several 12/24v computer fans on the boat and none have failed in over 10yrs.

Ditto. I've had two computer fans installed to create airflow over the fridge coils for the past six years. They come on only when the compressor's pumping. Cheap Maplin jobs, but they still work.

 

[Cardo]

Coming back to this thread. The extractor fan in our heads is probably on its last legs. Whilst it seems to work, it is the noisiest thing on the boat (well, second to the heater). I think the bearings have probably given up the ghost.

Having read this thread, I'm contemplating replacing with a cheapo computer fan. Has anyone tried using one in the heads? Obviously, there will be more humidity there and some water may splash onto it. Don't know how badly they are affected?

 

[lustyd]

Coming back to this thread. The extractor fan in our heads is probably on its last legs. Whilst it seems to work, it is the noisiest thing on the boat (well, second to the heater). I think the bearings have probably given up the ghost.

Having read this thread, I'm contemplating replacing with a cheapo computer fan. Has anyone tried using one in the heads? Obviously, there will be more humidity there and some water may splash onto it. Don't know how badly they are affected?

Give one a go - they are cheap enough that you probably won't be too upset if it does break. Remember that most "specialist marine" goods are just standard items which happen to be sold in a chandlers