Welcome! Log In Create A New Profile


Fan selection?

Posted by clearlynotstefan 
Fan selection?
May 20, 2017 06:50AM
I'm working on a part cooling fan and wanted to know which fans I'm looking for. I ordered these:2pack 50mm x 15mm 5015 12V Dual Ball Bearing DC Brushless Cooling Blower Fan BB5015H12 with 2 Pin Terminal UL TUV [www.amazon.com]

And they work great but don't respond to pwm at all,, they're binary at 100% or completely off. This leads me to believe that lowering the voltage, 2 pin pwm doesn't work, which makes me wonder, which fans do I need to get 50% airflow at 50%?

Edited 1 time(s). Last edit at 05/20/2017 05:34PM by clearlynotstefan.
Re: Fan selection?
May 21, 2017 03:58PM
Some fans does not work with PWM signal, but does work with voltage signal. To achieve that simply put a capacitor (I used 47uF) on power cables going to fan, it will smooth the PWM to some almost-constant voltage and let you control the fan speed winking smiley
Re: Fan selection?
May 21, 2017 05:40PM
I don't advise using a capacitor to smooth the PWM because it causes high peak currents through the MOSFETs unless you also use a series resistor. Some fans just don't work with PWM. Other fans work with low frequency PWM, so try adding parameter F100 to your initial M106 command.

Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
Re: Fan selection?
May 23, 2017 02:18AM
Another warning about the capacitor: If you change the polarity of the wires by accident, it will blow (happened to me).
Sorry, only registered users may post in this forum.

Click here to login