Author Topic: Interesting video on ferromagnetic behavior  (Read 763 times)

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Offline WattsThatTopic starter

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Interesting video on ferromagnetic behavior
« on: September 10, 2022, 04:07:21 am »
It starts out as a video about induction heating and then moves into magnetic domains.

 

Online KE5FX

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Re: Interesting video on ferromagnetic behavior
« Reply #1 on: September 10, 2022, 06:07:35 am »
I'm surprised I've never heard of this channel before.  Super impressed with the first couple of videos chosen more or less randomly.
 

Offline PartialDischarge

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Re: Interesting video on ferromagnetic behavior
« Reply #2 on: September 10, 2022, 06:12:50 am »
I'm surprised I've never heard of this channel before.  Super impressed with the first couple of videos chosen more or less randomly.

What I like about his videos are that they are relatively short and goes straight to the point with curious effects on physical ,chemical, electronic effects.
 

Offline RoGeorge

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Re: Interesting video on ferromagnetic behavior
« Reply #3 on: September 10, 2022, 06:36:09 am »
I'm surprised I've never heard of this channel before.

You never heard of "The Action Lab" channel because you don't visit the "Fun for nerds" topic, that's why!  :P
https://www.eevblog.com/forum/chat/fun-for-nerds/msg3613091/#msg3613091

Indeed, one of he most interesting science experiments channels on YouTube.
To me, "The Action Lab" is the best YouTube channel for physics experiments.  :-+

Offline mag_therm

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Re: Interesting video on ferromagnetic behavior
« Reply #4 on: September 10, 2022, 03:24:56 pm »
Re the video in o.p. on magnetic effects and induction heating.

The opening statements and the explanation of the "friction"  of Barkhausen effect being a cause of induction heating of cold steel
( penny demo  etc) is about  97% incorrect.

The effects described in the video were quantified by Charles Steinmetz before 1900 and his law , with minor additions, is still accurate and used today to measure losses in magnetic cores.
These losses do occur during induction heating of steel bars and pennies, but the dominant effect is Joule heating by eddy currents distributed with high intensity at surface of metal due to the skin effect.

To quantify the power losses in Watt/kilogram of typical annealed automotive grade steel:

1) Magnetic losses by Steinmetz: 2.2 Watt/kg at 60 Hz and 110 Watt/kg at 3000 Hz
Ref: Bozorth page 514, hysteresis loss for various steels and magnetic materials.

2) Joule heating of cold steel by eddy current (induction) : 3800 Watt/kg
Ref: Peak power density in the cold steel from a typical induction heating inverter rated 4000 kW producing about 10000 ~ 12000 kg of steel per Hour.

The author of the video failed to inform of the basics, failed to check the above comparison and is stating that he is demonstrating an effect when it is only about 2.9 % of the actual effect.
 


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