Voltage spikes calculation

Thread Starter

bootloader9800

Joined Jan 12, 2021
27
Hi guys, newbie here. Good to see a forum like this.
So here is my first question.

I have an Oscope. I wanted to know the peak current that was being pulled by a DC motor under load.
When I hooked up the Oscope, I was expecting a clean jump on the screen where the voltage line went from 0 to whatever voltage.

What I saw was spikes of all sorts at high resolution of the X - Axis.

Also, the math is showing that the current is 48 Amps, which can't be, since the power supply that was running the motor could give out only a max of 30 Amps.

How would one go about calculating the voltage in this case?
Thx
 

BobTPH

Joined Jun 5, 2013
3,304
Yep, motors cause all kinds of noise. You will never see a clean signal.

Your 30A power supply may well supply a peak current of 45A for a short time.

If you want more, snap a picture of the trace and post it.

Bob
 

Thread Starter

bootloader9800

Joined Jan 12, 2021
27
Yep, motors cause all kinds of noise. You will never see a clean signal.

Your 30A power supply may well supply a peak current of 45A for a short time.

If you want more, snap a picture of the trace and post it.

Bob
Here is the screenshot. I would like to know how to find the voltage. The voltage is not a straight defined line.
 

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