Voltage regulation

[jesse nobles]

Look for advice on the best way to handle this setup.

(1)12vdc 62amp source. (From a Dell server 2950)

(15 ) Fans. Variable speed between 6vdc to 12vdc(2amp) (out of dell servers also)

They will be used to cool individual animal cages in a straight run.

I'd like to control the voltage/speed of fans with one knob/switch but not sure what to use? 15 fans at 12vdc would pull 30amp?

or 2nd option just have them all run at 8vdc. Im guessing a resistor at each fan?

 

[Harald Kapp]

Use a PWM motor controller. This is an example. Less expensive ones can be found.
PWM is so much more effective than resistors in this application.

 

[Bluejets]

Maybe series each pair of fans?
Too much?

 

[CDRIVE]

You didn't mention if any of this is to be automated. In other words what determines fan RPM? The PWM Controller that Harald linked to can be controlled by means other than the on board POT; ie Thermistor control.

Chris

 

[CDRIVE]

Maybe series each pair of fans?
Too much?

This approach tweaked me so I started drawing a switch over scheme from series to parallel. Damn it gets messy!

Chris

 

[jesse nobles]

You didn't mention if any of this is to be automated. In other words what determines fan RPM? The PWM Controller that Harald linked to can be controlled by means other than the on board POT; ie Thermistor control.

Chris

The RPMs are controlled by voltage from what I know. Between 6 (lowspeed)to 12(highspeed) volts. Some type of automation would be nice, but manual control is fine for now.

If I wanted to salvage a PWM can you think of anything that would have them. I can run multiple lines with less fans to reduce max current and use smaller PWMs.

Also on a PWM. If my source is 12vdc. Do PWMs upstep voltage if they are rated 6-36vdc? Or limited by your source voltage?

 

[jesse nobles]

This approach tweaked me so I started drawing a switch over scheme from series to parallel. Damn it gets messy!

Chris

Yes. I thought about that, but very messy.

 

[CDRIVE]

The RPMs are controlled by voltage from what I know. Between 6 (lowspeed)to 12(highspeed) volts. Some type of automation would be nice, but manual control is fine for now.

If I wanted to salvage a PWM can you think of anything that would have them. I can run multiple lines with less fans to reduce max current and use smaller PWMs.

Also on a PWM. If my source is 12vdc. Do PWMs upstep voltage if they are rated 6-36vdc? Or limited by your source voltage?

Yes, you can use multiple controllers Like This.

The 12V - 40V rating is the input voltage range of the controller. It doesn't mean 12V in 40V out.

PWM does not boost or reduce voltage to the load. They function by rapidly switching the load ON - OFF. It's called Pulse Width Modulation because the width of the ON time vs the OFF time controls the motor speed with very little loss in torque. This is far superior to a variable voltage speed control.

Chris