Harmonics in 12 V DC Brushed Motors

Thread Starter

sharmark

Joined Sep 23, 2019
2
Hello guys,

I got a small 12V DC brushed motor and collected its current data. After performing the FFT of the signal, I found there are multiple orders present many of which I didn't expect. as motor has 12 commutators I saw a 12th order and maybe due to shakiness of brushes I saw some 24th order too. Also, there was a 5th order, which my colleague suggested is due to the sin winding on motor. but there are other orders like 7, 19, 36, etc

It would be great if someone can explain the presence of these orders

Thanks
 

Thread Starter

sharmark

Joined Sep 23, 2019
2
You may be seeing brush noise from arcing.
definitely there will be harmonic corresponding to the arcing but will they have the frequencies mentioned above ?

Also there are many more components of noise which are much lower in amplitude, I expected the arcing to be one of them. but its a point worth considering ?
 

ronv

Joined Nov 12, 2008
3,770
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