Author Topic: Magnetic fields within a toroid inductor. (Read 87777 times)

Magluvin · « **Reply #45 on:** September 15, 2013, 05:54:55 AM »

Quote from: poynt99 on September 15, 2013, 05:36:13 AM

The idea is to understand that there is a changing (increasing and decreasing) B-field within the core. This changing B-field is created by the primary coil and is "conducted" all the way around the core by the core material. Since the secondary happens to be in the direct path of this changing B-field, the resulting changing E-field around the secondary (in the same plane) causes the secondary induced emf.
Correct. The E-field is a product of the changing magnetic field. The changing magnetic field from the primary is caused by current in the primary, which of course is caused by voltage applied to the primary coil.
I mean that the flux "travels" around via the core to the secondary, where it goes through the "hole" of the secondary coil.

There is an E-field produced at every point around the toroid (perpendicular to the B-field), no matter if there is a coil situated there or not. When we properly place a coil in the path of the B-field, the coil "intercepts" the resulting E-field and hence has an emf induced in its windings.

Hey Poynt

Have you read the pdf I posted? I put it here again.

When you have time. If you havnt, please check it out. It makes a lot of sense.

When a wire has a rising voltage imposed upon it, a B field expands around the wire. So in our primary, the individual wires are the origin of the magnetic field produced by input. So why is that not the case with a toroid transformer, or any other closed core transformers? How could ther not be any flux outside of the core in those windings, where the flux originates?

If you havnt read the pdf, give it a gander.

18 pages. Let me know what you think.

Thanks

Mags

Magluvin · « **Reply #46 on:** September 15, 2013, 06:14:08 AM »

Hmmm, just thought of a good example. Hopefully.

If we have a straight rod core with a coil wrapped around it, we can understand that the inner parts of the flux loops of the coil will be in the core and out of the ends, they loop out expaded in space/air.

Now lets take a C shaped core and wind just on the left of the C, in the middle leaving some length of the core, top and bottom of the C without wire on it. Now imagine, from what you know, what do the fields look like now? There should be much stronger flux between the upper and lower C core legs, and then anything outside of the C as a whole is less dense.

So now, we close off the C core into a toroid. Can we not see that the flux crosses over the open space inside the toroid hole as the field expands from the primary?

Mags

poynt99 · « **Reply #47 on:** September 15, 2013, 06:14:12 AM »

Mags.

I read Distini ages ago, and I re-read some of the one you posted. I think he has some incorrect notions.

The B-field around the individual wires combine to form a concentrated field within the core. Beyond the surface of the wire itself, there is very little flux.

Build a toroid coil and get a Hall sensor to test it out yourself.

Magluvin · « **Reply #48 on:** September 15, 2013, 06:36:05 AM »

Quote from: poynt99 on September 15, 2013, 06:14:12 AM

Mags.

I read Distini ages ago, and I re-read some of the one you posted. I think he has some incorrect notions.

The B-field around the individual wires combine to form a concentrated field within the core. Beyond the surface of the wire itself, there is very little flux.

Build a toroid coil and get a Hall sensor to test it out yourself.

I got some hall sensors coming this week.

Thanks for your time Poynt.

Mags

tinman · « **Reply #49 on:** September 15, 2013, 08:04:16 AM »

So am i right in understanding that the current loop is strongest at the center of the toroid core? or is it the magnetic field that is strongest at the center of the core-or both?.

Dave45 · « **Reply #50 on:** September 15, 2013, 12:55:30 PM »

The B field and A field are two seperate fields, when you understand this things start to make sense. All the nonsense about particles popping in and out of dimensions is ludicrous.
If current is moving away from you in a wire the A field is coming towards you, the A field moves opposite the applied current, when I say current direction I mean neg to pos.
Using a single toroid the A field will loop the toroid but using two toroids the A fields of both toroids will join and loop both toroids, if wound and connected right.
The A field can also be spun between the two toroids if the winding is wound as I have showed.
If you look at the pic of the solenoid froze in ice you can see the A field. I have seen this field spinning in my ice experiments using a toroid,it creates a vortex.

Dave45 · « **Reply #51 on:** September 15, 2013, 01:49:04 PM »

Once you understand this concept you can see exactly how Ed leedskalnin's PMH works, there is a magnetic field flowing in the toroid and an electric field flowing in the air looping through the toroid, as long as the magnetic field is not interrupted the fields will continue for years, but when the magnetic field is broken the electric field collapses into the coils and will light a bulb. There are quite a few vids on youtube showing this effect.
simple simple simple
Ac reverses the magnetic field within a toroid this change in magnetic field direction causes the electric field to collapse into the secondary and we get a transformer. simple simple simple

xee2 · « **Reply #52 on:** September 15, 2013, 03:31:25 PM »

Quote from: tinman on September 15, 2013, 08:04:16 AM

So am i right in understanding that the current loop is strongest at the center of the toroid core? or is it the magnetic field that is strongest at the center of the core-or both?.

The current is the same everywhere in the wire. The magnetic field is strongest inside the toroid along a circle whose points are at the centers of the cross-sections of the toroid. In the same way that the magnetic field is strongest along the center line of a solenoid coil. The toroid coil is like a solenoid coil bent into a circle.

EDIT 1: Theoretically the field inside the toroid is uniform, not stronger in the center because the toroid is like an infinitely long solenoid.

EDIT 2: MileHigh has pointed out that this still is not correct, the magnetic field is strongest at the inner edge of the toroid because the toroid does not have equal length sides like a solenoid.

poynt99 · « **Reply #53 on:** September 15, 2013, 03:40:28 PM »

Quote from: tinman on September 15, 2013, 08:04:16 AM

So am i right in understanding that the current loop is strongest at the center of the toroid core? or is it the magnetic field that is strongest at the center of the core-or both?.

I'm not sure what you mean Brad.

By "current loop" do you mean the secondary winding?

By "center of the toroid core" do you mean the center of the "doughnut hole" or the center of the toroid core cross-section?

See also xee2's post, above.

MileHigh · « **Reply #54 on:** September 15, 2013, 03:53:32 PM »

Xee2:

Quote

The magnetic field is strongest inside the toroid along a circle whose points are at the centers of the cross-sections of the toroid. In the same way that the magnetic field is strongest along the center line of a solenoid coil. The toroid coil is like a solenoid coil bent into a circle.

Unfortunately that's not correct. Please have a look at the clip I linked to again:

http://www.youtube.com/watch?v=pCSHcftPAIM

MileHigh

Dave45 · « **Reply #55 on:** September 15, 2013, 04:06:51 PM »

The magnetic field is strongest closest to the center (see pic) but the magnetic field is contained and really is of no concern other than using it to control the electric field.

poynt99 · « **Reply #56 on:** September 15, 2013, 04:12:28 PM »

Quote from: MileHigh on September 15, 2013, 03:53:32 PM

Xee2:

Unfortunately that's not correct. Please have a look at the clip I linked to again:

http://www.youtube.com/watch?v=pCSHcftPAIM

MileHigh

MH,

xee2 is correct. He is referring to the cross-section of the toroid "tube", not the doughnut hole of the toroid.

MileHigh · « **Reply #57 on:** September 15, 2013, 04:38:42 PM »

Poynt:

Quote

He is referring to the cross-section of the toroid "tube", not the doughnut hole of the toroid.

I know that he is referring to the cross-section of the tube. The magnetic field is strongest inside the toroid tube along a circle whose points are hugging the inside wall (closest to the center of the doughnut) of the cross-section of the toroid.

B = u₀*N*I/2*Pi*r

The magnetic field strength inside a toroid (center of toroid when sliced like a bagel) is proportional to the number of turns and the current, and inversely proportional to the distance from the center of the doughnut.

The above formula is for an air core. For the case when there is a ferromagnetic core, just multiply it by the relative permeability of the core material.

MileHigh

xee2 · « **Reply #58 on:** September 15, 2013, 04:56:18 PM »

Quote from: MileHigh on September 15, 2013, 03:53:32 PM

Xee2:

Unfortunately that's not correct. Please have a look at the clip I linked to again:

http://www.youtube.com/watch?v=pCSHcftPAIM

MileHigh

If your point is that the field is uniform inside the toroid, I agree. I was trying to show that it was centered inside of the toroid and got sloppy. For an infinitely long solendoid, the field is uniform inside the solendoid. And, since a toroid is like a solelnoid bent into a circle, the toroid is like an infinitely long solenoid since it has no ends. Therefore, the field inside the toroid is uniform and is not stronger at center than at edges. Is that what you were pointing out? Is there something else that was wrong?

poynt99 · « **Reply #59 on:** September 15, 2013, 04:57:58 PM »

That's true. However, the "dl" factor tells us that the integral of B around the full toroid loop should be the same within the inner and outer radius.

If the radius of the toroid is >> than the radius of the cross-section, then the B-field intensity inside the toroid core will, for practical purposes be constant from the inner to outer radius.

Cookie	Origin	Persistency	Information and Usage
ecl_auth	overunity.com	Expires after 30 days	This cookie contains the text "EU Cookie Law - LiPF cookies authorised". Without this cookie, the Forums' software is prevented from setting other cookies.
SMFCookie648	overunity.com	Expires according to user-chosen session duration	If you log-in as a member of this site, this cookie contains your user name, an encrypted hash of your password and the time you logged-in. It is used by the site software to ensure that features such as indicating new Forum and Private messages are indicated to you. This cookie is essential for the site software to work correctly.
PHPSESSID	overunity.com	Current session only	This cookie contains a unique Session Identification value. It is set for both members and non-members (guests) and it is essential for the site software to work correctly. This cookie is not persistent and should be automatically removed when you close the browser window.
pmx_upshr{NAME}	overunity.com	Current session only	These cookies are set to records your display preferences for the site's Portal page if a panel or individual block is collapsed or expanded
pmx_pgidx_blk{ID}	overunity.com	Current session only	These cookies are set to records the page number for the site's Portal page if the page for a individual block is changed.
pmx_cbtstat{ID}	overunity.com	Current session only	These cookies are set to records the expand/collapse state for a CBT Navigator block content.
pmx_poll{ID}	overunity.com	Current session only	These cookies are set to records the id for the current poll in a multiple Poll block.
pmx_{fadername}	overunity.com	Current session only	These cookies are set to records the state for a Opac-Fader block.
pmx_LSBsub{ID}	overunity.com	Current session only	These cookies are set to records the current category and the state for a static Category block.
pmx_shout{ID}	overunity.com	Current session only	These cookies are set to records the current state of a Shout box block.
pmx_php_ckeck	overunity.com	Page load time	This cookie will probably never see you. It is set, if a Syntax check on a PHP block is initiated and will be deleted if the function executed.
pmx_YOfs	overunity.com	Page load time	This cookie will probably never see you. It is set on portal actions like click on a page number. The cookie is evaluated on load the desired page and then deleted. It is used to restore the vertical screen position as before the click.

1	We are aware that Google uses additional cookies it stores on your PC and when you browse our site and all other sites. These are used to target advertising and Google currently does this without seeking your permission. Four of these cookies we know about are named "rememberme", "NID", "PREF" and "PP_TOS_ACK" and are stored in Google's cache on your computer.
2	If you are accessing this site using someone else's computer, please ask the owner's permission before accepting cookies.
3	Your browser provides you with the ability to inspect all cookies stored on your PC. In addition your browser is responsible for removing "current session only" cookies and those that have expired; if your browser is not doing this, you should report the matter to your browser's authors.
4	We regret and apologies for any inconvenience this causes to members and guests who are accessing our web site from outside the European Union. It is not currently possible for us to interrogate your browser and obtain geographic location information in order to decide whether or not to prompt you to accept cookies.

Free Energy | searching for free energy and discussing free energy

News:

User Menu

Author Topic: Magnetic fields within a toroid inductor. (Read 87777 times)

Magluvin

Re: Magnetic fields within a toroid inductor.

Magluvin

Re: Magnetic fields within a toroid inductor.

poynt99

Re: Magnetic fields within a toroid inductor.

Magluvin

Re: Magnetic fields within a toroid inductor.

tinman

Re: Magnetic fields within a toroid inductor.

Dave45

Re: Magnetic fields within a toroid inductor.

Dave45

Re: Magnetic fields within a toroid inductor.

xee2

Re: Magnetic fields within a toroid inductor.

poynt99

Re: Magnetic fields within a toroid inductor.

MileHigh

Re: Magnetic fields within a toroid inductor.

Dave45

Re: Magnetic fields within a toroid inductor.

poynt99

Re: Magnetic fields within a toroid inductor.

MileHigh

Re: Magnetic fields within a toroid inductor.

xee2

Re: Magnetic fields within a toroid inductor.

poynt99

Re: Magnetic fields within a toroid inductor.