Need some help understanding 4pin molex to 3pin fan cables..

[scousenet]

Trying to understand what all the wires are for, in relation to connecting my YS-Tech 120mm cpu fan to my Akassa Fan Controller...

The fan has a 4pin molex connector, and Ive been told to get a 4pin to 3pin adapter, to connect it to the 3 pin connection on the fan controller...

http://www.akasa.co.uk/akasa_english...cb423_adpt.htm

However, the 3pin connector only has 2 wires.. and I just wanted to confirm that these would be for the power (obviously) and the other for fan speed???

Thanks.. and sorry for the lame question!!!

[scrandman]

Nope - power only.

Yellow is +12V, black is neutral. The 4 pin molex is +12, +5 & 2 neutrals, so it isn't possible to get a fan speed monitor wire from it to a 3-pin plug.

[scousenet]

Thanks...but dont normal fans you would use for a cpu, have a 3 pin connector, and report the fan speed??

Or is this just a limitation of a fan with a 4 pin molex..??

[_dangtx_]

the 3rd wire goes to mobo or a fan controller.
u can set it up on 9,7 or 5 volts if u need to.

[OakIris]

I have a related question. Some etailers give you a choice of getting a 3-pin or 4-pin tail for your fans. Under what circumstances would you want the 4-pin connector?

Holly

[StompinRound]

if you have more fans than motherboard fan headers, or you want to remove the load from passing through the mobo (very good for high rpm fans...they "can" burn out the traces in the mobo)

[OakIris]

StompinRound - I understand - the 3 pin is just for connecting to the mobo, which you shouldn't do with fans such as the Tornado. I think I knew that, just got confused for some reason.

Holly

[StompinRound]

some separate fan controllers use 3 pin fans, some use 4 pin. it usually depends on whether you need or want rpm monitoring or not

[scousenet]

Well I connected the fans 4 pin molex, to the adapter, then connected the 3 pin connector to the fan controller.. and it dont work!!! There is a power connector going to the controller, which I assumed would provide power to the fan, but it never moved!!

[PowerHungry]

You can use three or four pin connectors even if you are not connecting directly to the motherboard, I do it all the time especially for blow hole fans.

I bought a connector from www.performance-pcs.com that has a 4 pin on one end so I can connect it to a line from the power supply with two three pin male connectors on the other end, never have had a problem.

Most resellers will offewr three pin tails or four pin tails, the only time the three pin is critical is when you need to use the RPM. BUT, you have to make sure your fan offers RPM sensoring, you would be surprised how many don't.