PWM on the fan output


 

IvanTrail

New member
So, I see something interesting. The fan output can be switched to PWM (like the servo output).

I also see that Bryan is an RC guy, which obviously puts him in the top 1% of the top 1% of cool guys. (BBQ wizard AND RC pilot??? What? 👍👍👍 )

This leads me to believe there was some thought to hooking the fan output to an ESC and then controlling an EDF fan assembly as a blower. I think a 6S 90MM fan unit should work....

😲😲😲
 

Bryan Mayland

TVWBB Hall of Fame
Haha an EDF. Maybe if you're running a forge!

The fan PWM output is actual true PWM though, not servo PWM. The servo PWM has a long dead time in between each PWM period (50Hz) and is only on for 1-2ms of the 20ms period. The fan PWM is continuous at ~490Hz with no dead time. If Pulse mode is selected as the output, the pulses won't be very clean on v4.2 / v4.3 boards due to the inductor in series with the output and that should be removed or shorted if more square pulses are desired. The servo output could drive an EDF though, but I think even a small one would just blast right through smoking temperatures.
 

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