simple question.....

Control: management of fans, temp/rpm monitoring via soft/hardware

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omega_1
Posts: 64
Joined: Mon Feb 14, 2005 1:59 pm

simple question.....

Post by omega_1 » Tue Feb 15, 2005 6:15 pm

and also probably dumb....but anyway...im curious....i have a fan controller that controlls 7-12v...and when I use it my fans lose their bright ness....however when i use my tt 92mm fan with its own controller ( came with one ) i can lower rpm without affecting led power....is there a way i can do that for my other fans ?

sthayashi
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Post by sthayashi » Tue Feb 15, 2005 8:40 pm

Does your 92mm TT fan lose LED brightness when hooked up to the other fan controller? Do you have pictures or links to pictures to help me out here?

One controller may use voltage regulation while the other using PWM (though I'm not entirely sure why that would make a difference).

The other possibility may simply be how the fan powers the LEDs. If they just use a voltage divider circuit, then reducing the voltage will reduce the LED brightness. But if they used a Zener diode to regulate the power going to the LED, then reducing the voltage won't do anything to the LEDs.

omega_1
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Joined: Mon Feb 14, 2005 1:59 pm

Post by omega_1 » Wed Feb 16, 2005 4:31 am

sthayashi wrote:Does your 92mm TT fan lose LED brightness when hooked up to the other fan controller? Do you have pictures or links to pictures to help me out here?

One controller may use voltage regulation while the other using PWM (though I'm not entirely sure why that would make a difference).

The other possibility may simply be how the fan powers the LEDs. If they just use a voltage divider circuit, then reducing the voltage will reduce the LED brightness. But if they used a Zener diode to regulate the power going to the LED, then reducing the voltage won't do anything to the LEDs.
yes, when i hook it up to my vantec nexus...and lower voltage, it loses its brightness....and then when i use its own lil controller it doesnt....just rpm...im at school right now...no pic....but heres a link to the fan and controller : http://www.thermaltake.com/dcfans/led/bluesmart.htm

ferdb
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Post by ferdb » Wed Feb 16, 2005 5:59 am

A guess would be that your fan controller is using the 3rd wire that's normally used for the RPM sensor for supplying full voltage to the LEDs, while it reduces the voltage to the fan motor itself.
You could check this hypothesis by connecting only the fan motor connections and not the 3rd wire. The LEDs should then dim when the fan speed is reduced.

It doesn't matter whether you use a PWM or linear fan speed controller, if you run the LEDs off the same supply as the fan motor they will get dimmer as you slow the fan down with the controller.

edz
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Post by edz » Wed Feb 16, 2005 6:15 am

Looking at the pictures, the set up might be this:

Code: Select all

   V+  --------------------------
                  |     |       |
                  |     |       |
                  TR    MC      |
                  |     |       |
                  |     |       |
                  -------       |
                     |          |
                     |         LED
                     |          |
                    FAN         |
                     |          |
                     |          |
    0V  -------------------------
where if you want Thermally regulated you plug in the thermistor where it says TR. If you want Manual Control, plug in the potentiometer where it says MC. For full speed, short across either the TR or MC.


The LED (and it's resistor) always has V+ volts across it regardless of the TR or MC. So adjusted the fan speed with the included controller has no effect on the LED brightness.

V+ is from the 3 pin lead that'll normally plug into your mobo - so it'll normally be 12V. But when you plug in to your other controller, you are varying V+ (from 5V to 12V or something). This changes both the fan speed and the LED brightness.

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