Fan transformers?

[candian bacon]

I have two 4" dc 12v fans. I want to use them too help cool my lights. What type of transformer do i need? I tested them with a 12v 300mA trans. but i want to be safe and not burn my house down.

One fan reads .16A
One fan reads .13A

will this set up work? can i get more out of these fans? or is this the safe range?

thanks

[wharyat]

300 mA will be fine to run them, .16A+.13A=.29A * 1000 = 290mA. good to go!

[candian bacon]

can you explan the 1000 = 290mA? maybe i can learn somthing today. lol

[candian bacon]

1000mA = 1amp?

[wharyat]

Yes, 1000mA in one amp

[candian bacon]

great thanks! I know there has been a lot of debate on the set up. 1 fan in the other out? what are your thoughts?

[wharyat]

I would say both in on one side with vents on the opposite side.

[jdbassin]

Well it almost works that way and it will if wired correctly. First .16a is the equivalent of 160ma it's just like doing fractions in school 1 amp+1000ma .16av100 +160 ma. Ok here lies the problem though. If you connect the red wires on each fan together and the black on each fan together then hook both reds to one lead and both blacks to the other lead your good. Your only drawing 290ma The transformer is rated @ 300ma so everythin is all good. But if you try too hook the two fans in series. Black on one fan to one lead the red on that same fan to the black on the other and the others red to the other lead you've created a whole new ball game. Increase resistance while maintaining the same volts and you've blown the amps all out of whack. Don't wanna give a complete lesson on resistance here but just be careful how you wire them it makes a difference



jd

[jdbassin]

probably better in the long run running two transformers anyway in case it on fails you still have on fan working


jd

[wharyat]

Thanks jd, I should have mentioned to keep the fans in a paralell arrangement.

[candian bacon]

good point jd. i will be running only one transformer. they will not be in series as you put it. Im thinking of placing the fans under my light fixtures (PC type) Pulling hot air out of the tank and sending it up out off the cabinet top. I could also place them one on each side of the cabinet above the tank between the water surface and the lighting. Im thinking that because hot air rises. the first system would work best? Would salt creep be to great this way? would it cause creep to build up on my pc lights. they are exposed with no glass sheild.

[wharyat]

That sounds like a good idea with the fans, you might get minimal salt creep nothing too bad I would think.

[Steve-O]

Whenever I have a portable device that goes bad, I always keep the transformer. They come in handy for thing like fans. I found one that was perfect to power my fan.