EE361-Electromechanical Energy Conversion

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# EE-361 ELECTROMECHANICAL ENERGY CONVERSION

## Ozan Keysan

[ozan.keysan.me](http://ozan.keysan.me)

Office: C-113 <span class="meta">•</span> Tel: 210 7586

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# Permanent Magnets

## Why do we use PMs?

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#Applications
<img src="http://www.cndailymag.com/images/about/application.jpg" alt="Drawing" style="width: 800px;"/>

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# History
<img src="http://www.magnetnrg.com/uploads/2/0/0/5/20054943/2633149.jpg" alt="Drawing" style="width: 750px;"/>
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# Neodymium Magnets (NdFeB)

### Strongest and most common (60% market share)
### Expensive (600 TL/kg, $85/kg)

[Levitating a man](http://www.youtube.com/watch?v=q9m-hHg0gFk), [Magnet smashing](https://youtu.be/Vt8NOdINJ1s?t=41s), [Crushing hand](http://www.youtube.com/watch?v=0t8yDnyOaQ8)

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# Magnetization Directions

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#B-H Curve of a Magnet

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### Desired Properties:
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### Large Remanence flux density (retentivity, point that crosses B axis)
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### Large [coercivity](http://hyperphysics.phy-astr.gsu.edu/hbase/solids/imgsol/coercivity.gif) (point that crosses H axis)
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![](https://www.electronics-tutorials.ws/wp-content/uploads/2013/08/mag20.gif)

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# Magnet Strength Comparison
<img src="http://www.kjmagnetics.com/images/blog/demag.curves2d.gif" alt="Drawing" style="width: 600px;"/>
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## Intrinsic vs Normal B-H Charateristics

### We can only measure normal curve

[More info about magnets](http://what-when-how.com/electric-motors/hard-magnetic-materials-permanent-magnets-electric-motors/), [Magnet Guide](http://www.allianceorg.com/pdfs/Magnet_Tutorial_v85_1.pdf), [Demagnetization](http://www.shinetsu-rare-earth-magnet.jp/e/design/)
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# Demagnetization of PMs

### If external magnetic fields get below the knee point, PM will lose strength
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# Demagnetization of PMs

## Recoil Line

### Magnets will loose strength if the reverse magnetic field goes beyond the knee point.

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# Magnets with Temperature
### Real Datasheet of Sm-Co (Samarium-Cobalt Magnet)
<img src="http://www.x-magnet.net/hard-magnet/images/Sm2Co17-YX-30A-Demagnetization-Hysteresgraph.gif" alt="Drawing" style="width: 600px;"/>

### Magnets become less stable with increasing temperature.
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# What is Magnetic Force?

### [Why magnets attract each other?](http://www.youtube.com/watch?v=uTcuDprmues) by Richard Feynman
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### [Magnets and Special Relativity](https://www.youtube.com/watch?v=1TKSfAkWWN0)

Reading Suggestion: [Eminim Şaka Yapıyorsunuz Bay Feynman](http://www.idefix.com/Kitap/Eminim-Saka-Yapiyorsunuz-Bay-Feynman-Merakli-Bir-Sahsiyetin-Maceralari/Richard-P-Feynman/Bilim/Populer-Bilim/urunno=0000000427673)

<img src="https://cdn-images-1.medium.com/max/2000/1*4MnjkvCDAAJt7d0KrvFBOw.png" alt="Drawing" style="width: 600px;"/>
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# Magnetic Circuits with Magnets, Load Line
## Example

[More info on load lines](https://ocw.mit.edu/courses/electrical-engineering-and-computer-science/6-061-introduction-to-electric-power-systems-spring-2011/readings/MIT6_061S11_ch11.pdf),

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# Magnetic Levitation
 
## Where is my hoverboard?
<iframe src="https://giphy.com/embed/XCdsB59vTowwM" width="400" height="200" frameBorder="0" class="giphy-embed" allowFullScreen></iframe><p><a href="https://giphy.com/gifs/michael-j-fox-marty-mcfly-hoverboards-XCdsB59vTowwM"></a></p>

### It's already [here](https://www.youtube.com/watch?v=7KtzyZKSuls)!
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### [How does it work](https://www.youtube.com/watch?v=s9rbMd9zEI4)?
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### [Superconducting Levitation](https://www.youtube.com/watch?v=VyOtIsnG71U) and [Real world maglev train](https://www.youtube.com/watch?v=USmxHC9C8Iw)

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## You can download this presentation from: [keysan.me/ee361](http://keysan.me/ee361)