Help with watts please

[jaelem]

Hi all im trying to make a cooler for my marine tank i have 6 small fans that are interlinked with each other and they are 12volts 0.8 watts i cant find a transformer to make them work is there anything i could use that would make them work
Thanks

 

[Marvo]

Are the fans 12V AC or 12V DC? If they're 12V DC then a transformer alone won't work because they output DC. Can you attach a photo of the fan setup so we can see it?

 

[tazz]

ok you have 6 x 12v 0.8watt fans wired in parallel
so 6 x 0.8w = 4.8w total
ok P/V=A (watts / Votage = Current)
So 4.8w / 12v = 0.4 Amps

Therfore your looking for a 12v 400mA or higher transformer

 

[jaelem]

they are dc

 

[tazz]

Then you need a dc power supply at the rating of 12vdc 400mA plus or rectify a 14v ac transformer to provide 12v dc (using bridge rectifier loss 0.5v per phase 1v drop Half wave)

 

[Darkwood]

Your fans as suspected are DC so you need to either add a bridge rectifier to the transformer output or purchase a DC power supply ..see link


| 10W 1 Output Switch Mode DIN Rail Panel Mount Power Supply, 12V dc, 0.84A |

 

[Darkwood]

Then you need a dc power supply at the rating of 12vdc 400mA plus or rectify a 14v ac transformer to provide 12v dc (using bridge rectifier loss 0.5v per phase 1v drop Half wave)

Soz Tazz posted same time ....

 

[jaelem]

Thanks for you help guys much appreciated

 

[Spoon]

Wouldn't it be easier and cheaper just to use something like this?
NC120P050PUK/E+ - PRO POWER - AC-DC POWER SUPPLY 12V 500MA 2.1MM | CPC UK

 

[Marvo]

I'd be tempted to go with a power supply at double the 400mA calculated figure, maybe even 1000mA. The price difference will be small.

 

[Spoon]

Maybe PTD-1210B - POWERPAX - AC-DC POWER SUPPLY, 12V 1A, 2.1MM EUP | CPC UK then.

 

[tazz]

That would do the job fine....you can buy from maplins, cpc, rapid, rs