How much heat do fan controllers generate?

G

gilga

[H]ard|Gawd
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I am looking to buy a fan controller to help quiet down some of my fans ( buying new fans is not an option). The fan controller would be mounted in a 5.25 bay that has a hard drive installed above it. I was eyeing the vantec nexus or the sunbeam model. In regards to the heat, is it generated constantly or is it only when the fans are turned down? Any help is greatly appreciated.
 
I did a little research and found that fan controllers that use pulse width modulation generate little heat compared to a rhoebus/rheostat. Can anyone confirm this and much heat does the vantec nexus generate

thanx!
 
Absolutely! PWM based controllers generate much less waste heat since they are pulsing the potential on/off at a high (fixed) frequency. On an oscilloscope it looks like a square wave. To 'increase' the voltage, you are actually just increasing the width of the square wave in the "1" position.

For high current application, PWM's can generate a lot of waste heat from their FET - but it is still trivial compared to the amount of waste heat that a similar current device would generate with a variable resistor in series.
 
thank you calebb!

In regards to the heat dissipation from a pwm fan controller, will the heat generated make it unsafe to place under a hard drive? What kind of temperature increases can i expect and what amount of heat should the fan controller put out?
 
For a fan controller, the PWM will probably not generate any noticeable heat at all!

If you were controlling 6 x 100 watt peltiers, it would be a different story. But for some fans that only draw a watt or two, you might generate 50 milliwatts per fan. Definitely not an issue.

(compare it to the fan control knob on the back of a PC - turn the speed down and feel how warm it gets (not very warm). A PWM controller will generate 90% less heat than that)
 
thanx for answering all of my questions calebb. Cheers to you!!!

I do have one last one, could you or some one else recommend me a good pwm fan controller? I was looking at the vantec nexus, but wasnt quite sure.
 
I had the vantec nexus and to tell you the truth, it makes just about no difference at all between the highest speed and the lowest. Not to mention that the second (it has 4) 3-pin jack stopped working after 2 weeks. I've never used any other fan controller so I can't suggest one, but DO NOT buy that cheap p.o.s.
 
Anyone got a suggestion on a good pwm fan controller, pickings seem to be slim
 
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