Power jitters

[HANKMARS]

When I scope out the output of a motor controller in operation, I often see a "chatter" of the sinewave. Is this due to REMF from windings or maybe reflected energy from a capacitive load trying to corrupt of make a phase shift of the power out? Let's assume my scope is triggered as finely as possible.

 

[kellys_eye]

Any non-resistive load will distort a sinewave. The collective for this is 'harmonic distortion'. It's usually catered for in the system design - so that it will continue to work - but can sometimes create issues with other items connected to the same source supply - which is where you have to be aware of potential issues and either cope with them or add protection.

 

[danadak]

What is your scopes model number ?

If you have FFT in scope you can look at harmonics to get clues
to sources.

Probing mains :

https://download.tek.com/document/3AW_19134_2_MR_Letter.pdf

Regards, Dana.

 

[HANKMARS]

Any non-resistive load will distort a sinewave. The collective for this is 'harmonic distortion'. It's usually catered for in the system design - so that it will continue to work - but can sometimes create issues with other items connected to the same source supply - which is where you have to be aware of potential issues and either cope with them or add protection.

I have always made the blind assumption that a torrid inductor just prior to output terminals, is fabricated and "tuned" as a filtering device to eliminate feedback from the load. Like I say, an assumption.

 

[HANKMARS]

What is your scopes model number ?

If you have FFT in scope you can look at harmonics to get clues
to sources.

Probing mains :

https://download.tek.com/document/3AW_19134_2_MR_Letter.pdf

Regards, Dana.

A vintage VIZ WO 555 15 MHz dual trace. Circa 1960s, 70s? Hey, for 25 dollars I'm satisfied. Even though it doesn't have the time base for gigahertz, it will still give good clues as to; is signal present? Does amplitude waver? Spikes? For any precision work at high freqs, I hold the client responsible for test equipment acquisition. High freq scopes, spectrum analyzers, whatnot. Momma don't allow no high dollar toys round here til she gets a bigger house and a new car. ; )