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Why is the frequency swinging

The 2nd picture shows the frequency of a coffee machine. I zoomed in on part (A) just before the coffee beans were put in.

The zoomed image (1st pic) shows how the frequency swings up and down.

So my question is, why does the frequency swing when the machine runs at maximum frequency. Or simply direct me to a website that gives a simple explanation
Original post by MentalAcrobatics
The 2nd picture shows the frequency of a coffee machine. I zoomed in on part (A) just before the coffee beans were put in.

The zoomed image (1st pic) shows how the frequency swings up and down.

So my question is, why does the frequency swing when the machine runs at maximum frequency. Or simply direct me to a website that gives a simple explanation


What do you mean by 'frequency of a coffee machine'?
Indeed.
The 1st graph axis is labelled "drehfrequenz", which translates as "rotary frequency". (Hz)
The 2nd picture, which is supposed to be a zoomed in version of the first has a vertical axis in unit "watt".
So I think the poster needs to explain exactly what's going on before he gets a meaningful answer.
The zoomed graph is showing a power fluctuation not a frequency fluctuation.
(edited 9 years ago)
Original post by Stonebridge
Indeed.
The 1st graph axis is labelled "drehfrequenz", which translates as "rotary frequency". (Hz)
The 2nd picture, which is supposed to be a zoomed in version of the first has a vertical axis in unit "watt".
So I think the poster needs to explain exactly what's going on before he gets a meaningful answer.
The zoomed graph is showing a power fluctuation not a frequency fluctuation.


The ringing and overshoots on the edges of the pulse train suggest a reactive load. Could be a low power stepper motor drive perhaps?

Or my guess is the machine uses a switch-mode power converter (SMPS) and the pulses are artifacts of the waveform chopper.

Meaningless until the OP replies.
(edited 9 years ago)

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