Do Fan Controllers reduce the power usage?

[Jedi2155]

Well, I was just wondering how the fan controller works. Currently i'm guessing that the fan controller would just reduce the voltage through resistors and converting that electricity to heat rather than it actually reduce the power consumption. Is this theory of mine correct or wrong?

I'm guessing this cuz once I had too many fans on a single channel and it near burn it out so i'm guessing all that electricty just gets converted to heat.

This is also a factor on whether or not I should get a new fan controller cuz 7 Smart Case Fan 2's and a Vantec 92mm tornado sucks up a lot of juice (about 51 watts for all case fans + CPU fans) and I was wondering if reducing the speed also reduces the power or just converts it to heat.

Thanks in advance for any info!

 

[HeaterCore]

Almost all fan controllers use resistors, so you might be burning off some heat. Not too much, though; remember, even at low speeds you're still running about half of the 12v rail into your fans.

A few controllers -- the only one I can think of offhand is the mCubed T-Balancer -- uses something different, called pulse width modulation, which I'm not even going to pretend to understand well enough to explain it.

-HC-

 

[Jedi2155]

Thats true about the 6 volt low speed, but 6 volts still mean i'm saving 25 watts. The main thing is, i wasn't sure if I have my electrical thinking correct in that resistors convert the power to heat or just stops it from being used.

 

[sodcha0s]

Resistors do convert power to heat. There is a formula for calculating the total usage and I'm sure a lot of people here could help you with that, however I'm not one of them... I work with electrical systems on Light Rail Vehichles, but I don't get into the formulas and theroies very much and it's been too long since I have.

PWM is a bit different, it uses a switch to turn the power off and on very quickly, creating a pulse like this: |__|"""|__|"""|__ The top represents on time, the bottom off time. By changing the amount of time power is on or off, you can control the speed of the motor. However there are "switching losses" involved which produce heat and naturally, also consume power.

 

[Jedi2155]

Thanks a lot! And I also now understand PWM with your explanation. Its very similar to Intel Thermal Throttling too in Pentium 4's then.