4 pin pwm fan question

[diavolos]

hi, i want to go from an ac/dc convertor to a speed controller to the fan itself....if i dont use the pwm and sense wire of my delta fan.....can i use a normal speed controller for 2 pin?

 

[NiHaoMike]

PWM really is the only right way to do it on a Delta. A standard PWM motor controller won't work and a buck converter might give you some adjustment, but it's pointless when you could just use a 555 chip.

 

[Bobnova]

Which Delta fan? Delta makes an awful lot of fans, ranging from low power through ZOMG power levels.

 

[NiHaoMike]

The 4 wire Deltas generally available in small quantities are the high power (1A and up) versions. The lower powered versions are mostly only available to OEMs. All 4 wire Deltas use their DSP motor drive technology. That basically means the control is very good, but you must use the PWM input to throttle it down.

The reason why the lower powered versions aren't generally available in small quantities is because there's not much demand outside of the OEM market. You might as well just throttle down the high powered versions. OEMs, however, would find it worthwhile to cut cost.

Regardless, none of the Delta fans (that I'm aware of) will work properly with a brush DC motor controller (what PWM motor controllers typically refer to) and while you might get some control with a buck converter, it's silly when using PWM on the speed control wire is cheaper and more effective.

 

[diavolos]

i have the delta tfc1212de...... well thanks a lot

 

[Bobnova]

You can use a normal non-PWM fan controller with that fan, but it needs to be able to deal with a power draw of ~47 watts, not many fan controllers can.

You're better off using a AC-DC12V power supply of some sort and build/buying a PWM fan controller to control the fan speed.

 

[NiHaoMike]

A possible solution is a switchable output wall wart, but it's hard to find ones that can do more than an amp or two (and are able to do 12V and under) and you'll only get 3 or 4 settings that work. Much easier to use a 555.

 

[diavolos]

Any links on the pwm fan controller....I am not sure what to look for....as cheap as possible...

 

[NiHaoMike]

http://www.overclockers.com/pwm-fan-controller
To get 5V from the 12V wall wart, use a 7805. (The circuit does not use very much power.)

 

[diavolos]

ok I think this can help...nice link....I also found this will it be good for converting the fan frome 4 pin to 3 pin http://www.ebay.com/itm/251310564631

 

[NiHaoMike]

That should work.

 

[diavolos]

the only thing i dont understand is... after the ac converts to dc...i will need a 3 pin female to plug it to the 3/4 pin adapter.... but i cant find an ac to dc that at least ends with a 3 pin controller..... i cant just wire my 3 pin with a positive and a negative can i?

sorry for being a noob

 

[NiHaoMike]

You'll have to make an adapter or splice the wires.

 

[diavolos]

Lets say I have a ac to dc adapter and I have the red and the black wire......since the adapter (4/3pin) I want to plug with is a 3 pin.....do I need to split one of the adapter wire into 2 to end up placing two red and one black wire to accommodate the 3 pin?

Or maybe I am overthinking this and only need to connect the red and black wire and connect them on a specific pin....

 

[NiHaoMike]

Just match up the positives and negatives. Leave the RPM (feedback) wire unconnected.

 

[diavolos]

alright thanks alot guys

 

[WhitehawkEQ]

You could use 1 of these PWM controller