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 Post subject: Steel Laminations for DIY Transformer
PostPosted: Apr Fri 12, 2019 8:23 pm 
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I'm wishing to build a C-I type transformer for experimenting. Does anyone know where I can find the "C" and "I" silicon-steel laminations? EdcorUSA.com does not have "C" laminations, only "E".

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 Post subject: Re: Steel Laminations for DIY Transformer
PostPosted: Apr Fri 12, 2019 9:39 pm 
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If your willing to do the work, you can cut the center leg out of E-I core laminations.

Jay


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 Post subject: Re: Steel Laminations for DIY Transformer
PostPosted: Apr Fri 12, 2019 10:30 pm 
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I know what E-I is, but what is C-I?

I thought that something with C was C-C

Will your application not work with E-I?

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 Post subject: Re: Steel Laminations for DIY Transformer
PostPosted: Apr Sat 13, 2019 1:40 am 
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E-I-E-I-O

https://www.magneticmetals.com/products/c-i-core

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 Post subject: Re: Steel Laminations for DIY Transformer
PostPosted: Apr Sat 13, 2019 2:07 am 
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What size will you need? I have a couple of new sets of C-C cores. The magnetic path is 0.5" x 0.5". The winding window it 0.5" x 1.125". I don't know what they intended were for but probably OK for audio transformers.

These appear to be wound rather than stacked cores. They were wound with a 0.5" strap into the oval shape and then the two sides were cut apart. They are sealed up in plastic material.

Jay


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 Post subject: Re: Steel Laminations for DIY Transformer
PostPosted: Apr Mon 15, 2019 6:01 pm 
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Thank you flyboy71. I'll see if I can get them there.

pixellany, The purpose of the transformer is to measure the efficiency of the laminate to divert a magnetic field. So it's not basically a transformer. Or probably wouldn't work well as one. I just want the laminate silicon steel because I think it would be a good carrier of magnetic waves.

I'll need to cut about 1/2" from the "C" or "I" side to place a magnet in the gap. Then I should be able to place a small compass on top of the other side to see how well it will point to the north pole of the magnet. Then I want to try different types of magnets to see which performs the best and at what gap differences.

Attachment:
C-I.png
C-I.png [ 75.83 KiB | Viewed 619 times ]


JnTX, would your transformers be large enough to cut a 1/2" gap in one end?

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 Post subject: Re: Steel Laminations for DIY Transformer
PostPosted: Apr Tue 16, 2019 1:32 pm 
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This is not making sense to me......"magnetic waves"??......"divert a magnetic field"??

Maybe you could tell us what the end goal is......

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 Post subject: Re: Steel Laminations for DIY Transformer
PostPosted: May Fri 10, 2019 2:34 pm 
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Pixellany, yes, I kind of got the idea you don't understand what I'm saying. Mostly because you literally said you don't understand what I'm saying. My intent here was to find a good size transformer core for my experimental project, which I actually drew a picture of. Since I have a little time though, I'll be happy to better explain the fundamentals to you.

A laminated core is a device that is mostly used in electrical transformers. I need one for an experiment that I'm working on. My experiment does not involve transformation. Cores can be built rom many different materials and in different shapes. My experiment is currently designed to use insulated laminations of silicon steel. The reason I chose this material is it's ability to operate steadily at certain variating temperatures while minimizing resistance in the form of eddy currents and other factors. Although most recently I decided that a powdered iron core could also meet my requirements.

A transformer converts electrical energy into magnetic waves through the use of an insulated and continuous electric wire (usually copper) which is wrapped as a coil around an iron/ferrite material popularly known as a "core".

The electric coated wire passes an alternating current. The alternating current in the coil causes the transformer core to create equal and opposite MAGNETIC WAVES. That's why it's called a transformer. It "transforms" alternating current into magnetic waves. It's pretty cool. I'm surprised they didn't explain that in your training.

But wait! The fun doesn't stop there. Because if you take another, second wire which has no electricity in it at all and coil it around the other side of the core then the magnetic waves that are traveling through the core will actually induce an electric current into the second wire! Which makes it a double transformer! One side of the core transforms an AC current into magnetic waves, and the other side of the core transforms those magnetic waves into an alternating electric current. It is a perfect symbiotic relationship! I suppose that's why I'm so drawn to it.

Honestly, I'm not sure exactly where your disconnect is but I suspect it is this: Did you know that transformer cores carry magnetic waves? Because they do. If you take an "I" core of (oh, say about a 6" length of ferrous material) and put magnets on either end (both in south to north flow), and then place a small compass on top of the "I" core, you will see that the compass will change itself to point and follow the magnetic waves to the north flow of the magnets. I'll draw another picture.


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ferrous.png
ferrous.png [ 20.26 KiB | Viewed 444 times ]

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 Post subject: Re: Steel Laminations for DIY Transformer
PostPosted: May Fri 10, 2019 4:00 pm 
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Wow!!---- a lot of stuff there.

Part of the confusion is the choice of words---some of your terminology is non-standard.

First, we normally talk about magnetic fields. Maxwell's equations describe the propagation of electro-magnetic waves, in which there are alternating magnetic and electric fields. However, in transformers and coils, we deal with magnetic fields---not waves.

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The alternating current in the coil causes the transformer core to create equal and opposite MAGNETIC WAVES. That's why it's called a transformer. It "transforms" alternating current into magnetic waves. It's pretty cool.....

No....
Start with a COIL---it generates a magnetic FIELD, based on either DC or AC current**. The magnetic "forcing function" is the product of current and the number of turns, and the actual FIELD produced is a function of the permeability of the core. Another semantic bit here: The core can be thought of as focussing or concentrating the field---not "diverting" it.
A TRANSFORMER has a minimum of 2 windings, and is used to "transform" either the applied voltage or current (which must be AC). We also speak of "impedance transformation"--eg in an output transformer.

Quote:
But wait! The fun doesn't stop there. Because if you take another, second wire which has no electricity in it at all and coil it around the other side of the core then the magnetic waves that are traveling through the core will actually induce an electric current into the second wire! Which makes it a double transformer! One side of the core transforms an AC current into magnetic waves, and the other side of the core transforms those magnetic waves into an alternating electric current. It is a perfect symbiotic relationship! I suppose that's why I'm so drawn to it.

No again: two windings makes it a transformer. One winding makes is a simple coil--also variously called a solenoid or choke.

Attachment:
copper.jpg
copper.jpg [ 10.93 KiB | Viewed 434 times ]

And another NO....
A conductor is defined as something with enough free electrons to support the propagation of an electric field. In spite of the popular water flow analogy, the electrons do not "flow" from one end of the wire to the other, and they certainly do not "shoot out" from the wire along the way.

Quote:
I'm surprised they didn't explain that in your training
I assure you that all of this was very well covered---BSEE (Caiif State Polytechnic University, 1968, with follow-on extension courses........and you?


**Side note: Wave motion--whether it be sound or E-M--is, by defintion, AC only. Magnetic fields can be AC or DC.

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 Post subject: Re: Steel Laminations for DIY Transformer
PostPosted: May Fri 10, 2019 7:34 pm 
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Pixellany

Did any of your Cal Poly courses use texts by Hugo Gernsback ?

Rich


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 Post subject: Re: Steel Laminations for DIY Transformer
PostPosted: May Fri 10, 2019 7:46 pm 
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pixellany wrote:
Wow!!---- a lot of stuff there.

Part of the confusion is the choice of words---some of your terminology is non-standard.

First, we normally talk about magnetic fields. Maxwell's equations describe the propagation of electro-magnetic waves, in which there are alternating magnetic and electric fields. However, in transformers and coils, we deal with magnetic fields---not waves.


Definitely my fault on the terminology. Just the way my brain works. Potato - potatah - they both taste good fried, right?. The core I need is not for transforming. It is for measuring magnetic wave strength through it. Do you have one I can possibly purchase?

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 Post subject: Re: Steel Laminations for DIY Transformer
PostPosted: May Fri 10, 2019 8:19 pm 
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Magnetic fields...
For experiments, why not just pull apart an old transformer and use the iron?

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 Post subject: Re: Steel Laminations for DIY Transformer
PostPosted: May Fri 10, 2019 10:21 pm 
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Quote:
magnetic wave strength through it


Flux density, maybe?

Image

Rich


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 Post subject: Re: Steel Laminations for DIY Transformer
PostPosted: May Fri 10, 2019 10:49 pm 
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Mugginsjr,

Not quite sure what you are hoping to demonstrate here. You can prove that a magnetic field passes through iron a lot easier than sawing up an old transformer. A soft iron bar, magnet, and some small steel tacks or nails will do nicely. The bar won't pick up the nails by itself, but put the magnet on one end of the bar and the other end will pick them up readily

Your understanding is off on a couple of points. Any time an electric current flows through a conductor, a magnetic field is created. Any time a magnetic field impinges on a conductor, it causes current to flow as long as the magnetic field is changing (increasing or decreasing in strength). Current is also produced if the conductor or the field move relative to each other, so the conductor cuts the magnetic lines of force in the field. These are physical phenomena which do not require the presence of iron or steel. Those materials are used in practical devices like transformers and motors to concentrate and focus the magnetic fields for better efficiency. If the conductor is wound into a coil, it will also concentrate the magnetic field. In a transformer, the primary coil is connected to a time-varying source of current, so it produces a time-varying magnetic field. That field impinges on the secondary coil which responds by producing a time-varying current or voltage at its terminals.

It might be mentioned that all practical conductors at room temperature work on the principle of electrical neutrality; that is, they have no positive or negative charge. If a source of EMF (electromotive force) like a battery or a generator is connected to a conductor, it attempts to "pull" or "push" the electrons in the conductor. These electrostatic forces are present throughout the conductor as long as the EMF is applied. If there is a conductive path back to the other side of the EMF source, those forces can push or pull the electrons at the other end and current can then flow. Copper is sometimes considered a non-deal conductor not because it leaks electrons but because at normal temperatures it has resistance. All ordinary conductors do, at least until you get down to superconducting temperatures. Resistance dissipates some of the EMF in the form of heat, so you always get less energy out of a conductor than you put into it.

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