Electric motors sheet metal stack construction properties

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I am curious as to why many electric motor stators or rotors are constructed from a "sandwich" of sheet metal stampings.

For instance: does the layer to layer electric isolation help reduce the induced currents on the components?

For what properties is it chosen that stators and rotors are constructed with this technique?

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TO THE FINDER... THE ISLE OF KOHOLINT, IS BUT AN ILLUSION... HUMAN, MONSTER, SEA, SKY... A SCENE ON THE LID OF A SLEEPER'S EYE... AWAKE THE DREAMER, AND KOHOLINT WILL VANISH MUCH LIKE A BUBBLE ON A NEEDLE... CAST-AWAY, YOU SHOULD KNOW THE TRUTH!

Last Edited: Tue. May 14, 2019 - 03:47 AM
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The (varnished) sheets reduce eddy currents.   Without that the eddy currents would suck up power and generate heat.

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Matt has it right.

The largest known prime number: 282589933-1

It's easy to stop breaking the 10th commandment! Break the 8th instead. 

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You can see some nice motor being made--they mention the current loss

https://www.youtube.com/watch?v=CBFE-Bt7RjY  

When in the dark remember-the future looks brighter than ever.   I look forward to being able to predict the future!

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Very helpful, thank you all

TO THE FINDER... THE ISLE OF KOHOLINT, IS BUT AN ILLUSION... HUMAN, MONSTER, SEA, SKY... A SCENE ON THE LID OF A SLEEPER'S EYE... AWAKE THE DREAMER, AND KOHOLINT WILL VANISH MUCH LIKE A BUBBLE ON A NEEDLE... CAST-AWAY, YOU SHOULD KNOW THE TRUTH!

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This brings a question to my mind. In the case of inductors, the eddy currents are reduced by using several materials, like ferrites (which have inherent low conductivity), powdered iron and laminated iron (which are coated by some insulator). But in the case of motors it's almost always laminated iron.

Is there a reason for this? Maybe mechanical, since ferrites are brittle?

Last Edited: Tue. May 14, 2019 - 11:35 AM
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El Tangas wrote:

This brings a question to my mind. In the case of inductors, the eddy currents are reduced by using several materials, like ferrites (which have inherent low conductivity), powdered iron and laminated iron (which are coated by some insulator). But in the case of motors it's almost always laminated iron.

 

Something I've red in the last couple of days said that it's Silicon Iron used in such places. And a Wikipedia search would tend to confirm this...

 

https://en.wikipedia.org/wiki/El...

#1 This forum helps those that help themselves

#2 All grounds are not created equal

#3 How have you proved that your chip is running at xxMHz?

#4 "If you think you need floating point to solve the problem then you don't understand the problem. If you really do need floating point then you have a problem you do not understand." - Heater's ex-boss

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While reading the silicon iron wiki article, I came upon a magnetic material I didn't know, amorphous iron. Interesting.

It's used in transformers, but using it for motors is apparently cutting edge tech:

 

https://www.machinedesign.com/mo...

 

https://www.hitachi.com/rd/porta...

 

I love learning stuff from random dives in Wiki articles yes

 

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El Tangas wrote:

I love learning stuff from random dives in Wiki articles yes

 

Same here. But I also have this bookshelf in the smallest room in the house to keep my brain active...

 

#1 This forum helps those that help themselves

#2 All grounds are not created equal

#3 How have you proved that your chip is running at xxMHz?

#4 "If you think you need floating point to solve the problem then you don't understand the problem. If you really do need floating point then you have a problem you do not understand." - Heater's ex-boss

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Silicone impregnated steel (iron) limits your hysteresis losses, which is from the magnetic poles flipping back and forth when exposed to an ac field the laminate them to prevent eddy currents.

If you made a motor without laminated sheets, the motor would probably melt down due to the heat from eddy currents

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That book in the middle "How to lie with Statistics" sounds interesting!   devil

 

Jim

Click Link: Get Free Stock: Retire early! PM for strategy

share.robinhood.com/jamesc3274
https://www.onegold.com/join/7134f67c2b814c5ca8144a458eccfd61

 

 

 

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Interesting book collection... So were you able to fossilize your hamster?

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Kuch wrote:
Interesting book collection... So were you able to fossilize your hamster?

Thankfully not. He's alive and well. In fact, as I type this, he's just climbed out of his house and is heading towards the kitchen.

#1 This forum helps those that help themselves

#2 All grounds are not created equal

#3 How have you proved that your chip is running at xxMHz?

#4 "If you think you need floating point to solve the problem then you don't understand the problem. If you really do need floating point then you have a problem you do not understand." - Heater's ex-boss

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ki0bk wrote:

That book in the middle "How to lie with Statistics" sounds interesting!   devil

 

Jim

 

That's a classic! I remember professors quoting that book.

The largest known prime number: 282589933-1

It's easy to stop breaking the 10th commandment! Break the 8th instead. 

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That book in the middle "How to lie with Statistics" sounds interesting! 

It's easily observed that more than half of the population is below average when it comes to being fooled by statistics!  

When in the dark remember-the future looks brighter than ever.   I look forward to being able to predict the future!

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Ferrite has been used in 3-phase Brushless Permanent Magnet motors for quite awhile now.  If you take apart your desktop computer's fan motor, you won't find stacked laminations.  It's hardly new and cutting edge anymore, whatever Hitachi would like to say about it.  S.

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avrcandies wrote:
more than half of the population is below average
... would you like to correct that statement? (my emphasis added)

 

Ross McKenzie ValuSoft Melbourne Australia

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valusoft wrote:

avrcandies wrote:
more than half of the population is below average
... would you like to correct that statement? (my emphasis added)

 

 

Actually it's perfectly normal, because there is a difference between average (as in arithmetic mean) and median.

This often happens when a variable has a minimum possible value, like zero, but no upper limit. Income is a good example.

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We probably need a topic split a few posts back, but it's a fact that most of the people on this planet have an above average number of feet.

#1 This forum helps those that help themselves

#2 All grounds are not created equal

#3 How have you proved that your chip is running at xxMHz?

#4 "If you think you need floating point to solve the problem then you don't understand the problem. If you really do need floating point then you have a problem you do not understand." - Heater's ex-boss