PC fan voltage regulation w/PSU plug?

[todanu]

I need to vary the speed of a PC cooling fan for use in a DIY magnetic stirrer and without a variable power supply unit, I figured that a universal power supply (UPS) plug might be a good substitute?



The fan I am interested in has the usual 3-pin and molex connectors:



Input Power: 6.36W

Rated Voltage: DC12V

Input Current: 0.28A



fan: https://www.amazon.co.uk/upHere-Computer-Coolers-Radiators-Airflow/dp/B078M4FR25/





The UPS plug supplies a current of 0.25A ~ 2000mA and 3V - 12V. The fan is rated 12V and 0.28A so it should be fine, but I’m unsure of the polarity of the fan, do I need to worry about that?



plug: https://www.amazon.co.uk/Universal-CUGLB-Switching-Selectable-Electronics/dp/B0776N1T6H





My main concern is connecting the two, I thought the LED Terminal connector would be my best bet, any ideas?

 

[pendragon1]

I need to vary the speed of a PC cooling fan for use in a DIY magnetic stirrer and without a variable power supply unit, I figured that a universal power supply (UPS) plug might be a good substitute?



The fan I am interested in has the usual 3-pin and molex connectors:



Input Power: 6.36W

Rated Voltage: DC12V

Input Current: 0.28A



fan: https://www.amazon.co.uk/upHere-Computer-Coolers-Radiators-Airflow/dp/B078M4FR25/





The UPS plug supplies a current of 0.25A ~ 2000mA and 3V - 12V. The fan is rated 12V and 0.28A so it should be fine, but I’m unsure of the polarity of the fan, do I need to worry about that?



plug: https://www.amazon.co.uk/Universal-CUGLB-Switching-Selectable-Electronics/dp/B0776N1T6H





My main concern is connecting the two, I thought the LED Terminal connector would be my best bet, any ideas?

yes that would work and the fan cable should have the polarity marked. if not, its always the same pin on a 3pin header

 

[todanu]

Many thanks, I suppose it would be wise to wait until I have the fan to find out.

Not sure I follow the schematic?

Even though a molex cable has four pins, there must only be three coming from the fan, if I were to use the LED Terminal connector, would I have to worry about Earth?

 

[pendragon1]

if the led terminal puts out between 6-12v it will work. when fans are connected to a molex they only use two wires, the power and ground and they will run at full blast.