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can I switch pos and neg on my fan?
derf - 2/11/05 at 05:00 AM

Can I do this to get my fan to blow insteag of suck? I am hooking the black wire up as neg, and going under the assumption that the blue wire is pos. Anyway I want my fan to blow instead of suck, so can I just switch the wires around to do this or will I screw up my fan?

I might need to make some room where the fan sits to place the steering rack.


gazza285 - 2/11/05 at 05:50 AM

You should be able to, but the fan blades are only designed to go one way. Better to get a proper blowing fan instead.


highspeeddirt - 2/11/05 at 07:27 AM

As well as reversing the wires you also need to take off the blade and fit it back on the other way round.

Steve


stevebubs - 2/11/05 at 11:14 AM

Need to make sure no bare metal is contactable on the fan if you do this.

If there is, this is likely to have gone from grounded to +12v so anything metallic touching it and another part of the car will cause a short.


gutball - 2/11/05 at 12:35 PM

Some fans are designed to be used as blow or suck, most not. You can tell from the shape of the blades - if they're straight and dont curve (in any direction) then its probably a blow/suck, otherwise its a one way only. However, thats not to say that it wont be sufficient, maybe. I think the bushes in the motor will prob wear more quickly as well.


dhollin3 - 2/11/05 at 01:08 PM

Yeah, don't worry about it and swap over the wires. This should reverse the fan. The motor will always out last the life of he cars use.

Anyway, if it doesn't work and the fan breaks, it won't cost much to get a second hand fan wil it!!!


JoelP - 2/11/05 at 06:39 PM

quote:
Originally posted by dhollin3
Anyway, if it doesn't work and the fan breaks, it won't cost much to get a second hand fan wil it!!!


unless the engine goes with it!

Mine doesnt even have the fan wired up and doesnt seem to be needed.


tks - 2/11/05 at 08:38 PM

its not always true that you can just switch the wires.

I'm pretty sure that on mine i cant do that..

when i brought it at the yard
and got home to test it..it only worked one way round!

i use an escort example if i'm right.
one with the blades connected to each other by an circular plastic ring.

when i put my fan on it sucks like hell, i can throw an piece of paper and it will stick to the rad, when i turn of it will fall down..

Tks


RazMan - 3/11/05 at 12:23 AM

My fan was blowing instead of sucking until I simply reversed the polarity. Oh and reversing the fan blades doesn't work - the fan blades still blow in the same direction (yes, really)
The down side will be that the brushes or commutator will wear more quickly - so it's a trade-off

[Edited on 3-11-05 by RazMan]


MikeRJ - 3/11/05 at 10:27 AM

quote:
Originally posted by RazMan
Oh and reversing the fan blades doesn't work - the fan blades still blow in the same direction (yes, really)


The point being made was that if the blades have an aerofoil shape, then they need to be reversed at the same time as the motor polarity, as running backwards they will be very inefficienct.