Author Topic: Punched laminate transformers  (Read 1002 times)

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Offline excitedboxTopic starter

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Punched laminate transformers
« on: December 27, 2019, 03:02:11 am »
I was just looking at transformers and thinking, why are they made out of flat laminates that are punched out instead of strips of steel that are stacked and bent?

It would be the same as wound coil transformers but with the cost benefit of stacking laminations. Is it more expensive to bend cut strips or is there an electrical reason for it? Isn“t it better to have flat wide eddy currents instead of having "thick" eddy currents in the stamped laminate?
 

Offline viperidae

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Re: Punched laminate transformers
« Reply #1 on: December 27, 2019, 05:57:54 am »
It's one less step I guess. Stamping if stamping. You can either stamp E and I shapes and stack them up, or stamp I shapes, then bend them, then stack them.

The bending method would also require different length pieces and bent at different spots so they can all fit together.
 

Offline T3sl4co1l

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Re: Punched laminate transformers
« Reply #2 on: December 27, 2019, 06:34:24 am »
Relative to the plane of the coil, either case is still narrow eddy currents.  Consider a single shorted turn, then think of a plate in the same plane: that would give "thick" eddy currents.  (And a much longer magnetic path, because of all the air gaps between plates in the stack.)

They do actually make them that way,
http://www.epd-inc.com/2011/08/hypersil-cores/attachment/003/
Efficiency can be higher because grain-oriented steel can be used.  They're also made of continuous strip, wound into shapes (toroids and rectangles), glued, and cut apart into halves, a format also very handy for nanocrystalline materials (very pricey, but extremely low loss at mains frequency).

Tim
Seven Transistor Labs, LLC
Electronic design, from concept to prototype.
Bringing a project to life?  Send me a message!
 

Offline excitedboxTopic starter

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Re: Punched laminate transformers
« Reply #3 on: December 27, 2019, 11:20:32 am »
Yes I know. I was just trying to describe the orientation. I didnt actually mean that the eddy currents were thicker . That is sorta what I am talking about and I have seen those. I mean E core transformers like that one in your link. I have only seen E cores as flat laminates. Seems like you could save material too if you made them out of segments like that.
 


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