CF633 Fan Load Query


New member

I have just purchaced two 120mm Sunon fans, and they are 6.8w each. And I am goint to use them as variable speed (633 PWM) fans on a radiator in my water cooling setup.

I read on another post that the maximum recomended load of all the fans is 1 amp.

So, 6.8w / 12v = 0.5666amp

And since there is two, 0.5666 * 2 = 1.1333amp

Is this still withing design tolerance for the unit, or should I design a small circut to drive them using the signal from the fan header via a mosfet?

Robert Heffernan
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CF Tech

The current draw of those Sunon's will not be a problem.

From the 633 data sheet:
+12v (fans): Draw on +12v for fans will vary, depending on the user equipment connected to FAN 1 through FAN 4. Maximum continuous current draw must be no more than 1.5A per fan connector, no more than 4A total. Pulsed current may be up to 5A per connector, the pulse width must be less than 50mS. This pulse specification allows for the fan’s start-up current spike.
We already have some pretty beefy MOSFETs in there :)
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New member
Aaah sweet!

Thanks, I thought for a minute there I may have had even more work to do on this case-mod project of mine!

Not that I would have minded :D

*Goes to start hacking big holes in a brand new Lian-Li PC75*