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### Author Topic: Tesla's "COIL FOR ELECTRO-MAGNETS".  (Read 459941 times)

#### MileHigh

• Hero Member
• Posts: 7600
##### Re: Tesla's "COIL FOR ELECTRO-MAGNETS".
« Reply #570 on: January 12, 2014, 11:54:42 PM »

Okay, let's assume that a vertical orientation on your monitor for purposes of this posting is equivalent to magnetic north-south.  Up is north and down is south.  Left is west and right is east.

I will simply use "(C)" for the compass.

I am going to use arbitrary simplified vales for the variables to illustrate the example.  The actual values for the variables (current level, distance between coil under test and the compass, the angles of deflection of the compass) will be up to you.

We are going state the following:

1.  It is very important to align the test setup along the magnetic north-south of the Earth.
2.  Zero amperes through the coil will deflect the compass by zero degrees from magnetic north.
3.  One ampere through the coil will deflect the compass by roughly 80 degrees from magnetic north.
4.  The distance between the pancake coil and the compass will be 30 cm.
5.  The fist thing you do is find a convenient table to put the compass on where it is magnetically undisturbed and points towards magnetic north.  You want to keep the compass away from other potential sources of magnetic field.
6.  Optionally, you can place the compass on a small block of wood or something similar so the compass is at the same height as the axis of your pancake coil.

Here is the top-view of the test configuration.

-----------------------------------------------------------
North
[]
[]
[]  <----- 30 cm ------>  (C)
[]
[]
South
-----------------------------------------------------------

The test:

When you put the same current through each coil for the same setup you should see the same amount of compass deflection for the two coils.   If you try a few different current levels and a few different distances/geometries and get the same results then you will have definitively proven that the two coil configurations generate the same strength of magnetic field.

Understanding the compass deflection:

The compass will be aligned with the ambient magnetic field.   The two sources for the ambient magnetic field are the Earth (north-south) and the coil under test (east-west).   Magnetic fields add like vectors so the compass will simply be showing you the vector addition between the two sources of magnetic field.

The addition of the two magnetic field vectors produces a diagonal field vector so the compass will be at some diagonal offset from magnetic north.  If you have graticule markings on the compass you will be able to make very accurate readings of the compass deflection.

Note that it would take "infinite current" flowing trough the coil to make the compass needle deflect by 90 degrees because of the vector addition.   That's why I arbitrarily stated that the compass would deflect by "80 degrees for one ampere of current flow."

The closer the deflection of the compass needle to 90 degrees the more "coarse" the measurement is because you are losing your "differential measurement sensitivity" and hence there is less information there.  I would suggest that you keep your compass deflection measurements between zero and 80 degrees or less.

There is nothing stopping you from putting high current through the coils for a perhaps 10 seconds so the compass reading can stabilize.  Naturally you can decide how far the distance will be between the coil under test and the compass and that will allow you to use lower current levels if you want to.

If you do choose to do the test have fun!

MileHigh

#### MileHigh

• Hero Member
• Posts: 7600
##### Re: Tesla's "COIL FOR ELECTRO-MAGNETS".
« Reply #571 on: January 13, 2014, 12:07:54 AM »

I can see that you already did a basic test.  I just tried to formalize the test in my long description to make it (hopefully) clear for anyone that wants to make some relative magnetic field strength tests between two or more coils.

MileHigh

P.S.:  You have a beautiful compass!

• Hero Member
• Posts: 1843
##### Re: Tesla's "COIL FOR ELECTRO-MAGNETS".
« Reply #572 on: January 13, 2014, 12:08:26 AM »
@MileHigh:

Thank for outlining a test in such a precise way. I will do this test tomorrow in exactly the way you designed.

You will see my post about a magnetic field test I did just now. I hope it was executed in the right way. (I am tired right now and have not yet carefully studied your test proposal, but I will tomorrow.)

And I will make a video about the magnetic field test. This will help all interested forum members to see what I did. Hopefully I will get many suggestions and constructive criticism.

MileHigh has now become the official educator of the OU forum. All his predictions came true and all his suggestions and improvements worked like a charm. I personally made a great leap forward in my understanding of basic concepts.

#### synchro1

• Hero Member
• Posts: 4694
##### Re: Tesla's "COIL FOR ELECTRO-MAGNETS".
« Reply #573 on: January 13, 2014, 01:01:47 AM »
I'm ready to clean both you clowns out on a gram of iron filings per joule of capacitor discharge magnetic attraction comparison between the two coils. I'm willing to bet any amount of money that I get a higher weight to power ratio with the Tesla series bifilar pancake. Come on now and try and pretend the coil has no magic! All those test results are completely inane and have nothing whatsoever to do with the coils true purpose as an "Impulse Magnetizer".

#### Magluvin

• Hero Member
• Posts: 5886
##### Re: Tesla's "COIL FOR ELECTRO-MAGNETS".
« Reply #574 on: January 13, 2014, 01:54:18 AM »
I'm ready to clean both you clowns out on a gram of iron filings per joule of capacitor discharge magnetic attraction comparison between the two coils. I'm willing to bet any amount of money that I get a higher weight to power ratio with the Tesla series bifilar pancake. Come on now and try and pretend the coil has no magic! All those test results are completely inane and have nothing whatsoever to do with the coils true purpose as an "Impulse Magnetizer".

Your right. Just applying dc, especially low voltage, if your not looking for it, you wont see it.

45pf, you better be looking for very high freq initial spike at the time of applying the dc, not just looking at the DC magnetic field after the spike.

Oh well. Cheap tests. Cheap results. Testing pancakes such as shown, the motor better be running somewhere below FM radio freq of rotation. Doing low freq or dc tests on a coil that is designed for radio freq doesnt make any sense to me.  And then to say the results are conclusive when it comes to the difference between bifi and normal coils is only half baked.

Just made a second bobbin to match a coil I have(normal 1 strand, 42awg, 5kohm, 1.6h 2 1/4 dia, 1/8 in thick) to make an equal bifi for comparison.  The normal coil lights an led with a slow pass of a mag.

Will be using a primary pulse coil of 2 turns on the outer diameter for testing.

Mags
« Last Edit: January 13, 2014, 05:14:09 AM by Magluvin »

#### Farmhand

• Hero Member
• Posts: 1583
##### Re: Tesla's "COIL FOR ELECTRO-MAGNETS".
« Reply #575 on: January 13, 2014, 03:55:14 AM »
Mags is right.

An electro-magnet is not defined only as something that is used to pick stuff up. (like with a magnet on a crane). An generator can have electro-magnets and they can be excited at a frequency, it's not restricted to Continuous Direct Current. Nor is the patent about spiral coils only, all coils are included.

The patent to me looks to be about using frequency. There are several references to it. But I don't see any reference to the field strength when excited by Continuous DC.

The patent is about negating the self inductance of the coil by exciting it at or around it's self resonant frequency, and that by winding it in the way described the self resonant frequency is lower and so easier to achieve.

In the very second post of this thread I showed the Coil For Electro-Magnets has a much lower self resonant frequency. As the patent says it would have a lower self resonant frequency for the same length, of the same wire, on the same core, I believe that is the object of the patent. If self resonance was wanted in a field magnet then we would simply use a capacitor nowadays. But it could maybe be done without the capacitor by using a Coil For Electro-Magnets, if the field was to be excited at a constant frequency it could be viable.

Everything outside of the scope of the patent is irrelevant to this topic as far as I see it. But please continue off topic what do I care.

..

Here's a thought. In a motor or generator with the field magnet coils self inductance negated by either a conventional modern external capacitor or by using a Coil For Electro-Magnets then I would imagine there would be an improvement to the Power Factor. Would there not ? Which would equate to an improvement in efficiency I guess.

..

Regular Field Magnet coil tuned with external capacitor = Coil For Electro-Magnets field magnet coil wound to order for the intended frequency (no capacitor).
More real power less reactive power.  The way to better efficiency.

..

I've got a transformer with eight primaries, four sets wound as double windings that can be configured as series connected bifilar coils, one each quarter. When one coil from two opposite quarters are connected in series (they are not bifilar like that) they measure 1.34 mH. I'll make some measurements and formulate an experiment in line with the patent to determine what external capacitor I would need to get self resonance at the same frequency as when the coils are connected as in the patent with no external capacitor.

..

#### Magluvin

• Hero Member
• Posts: 5886
##### Re: Tesla's "COIL FOR ELECTRO-MAGNETS".
« Reply #576 on: January 13, 2014, 04:16:55 AM »
Was thinking of the Leedskalnin magnet holder.  If we have a U core with a bar core to close the end, a normal coil will produce a certain amount of field in the core to hold the bar core to the U core.  So if the bifi produces a higher initial field, the cores should lock in more than the normal coil. To find out, there would have to be a very specific and exact way of repeatedly being able to break the bar from the U, to measure the amount of output a pickup coil produces, or use weight to break the magnetic bond. Then there should be a difference in how much weight it takes to break the bond.

Mags

#### Magluvin

• Hero Member
• Posts: 5886
##### Re: Tesla's "COIL FOR ELECTRO-MAGNETS".
« Reply #577 on: January 13, 2014, 04:23:17 AM »

Here's a thought. In a motor or generator with the field magnet coils self inductance negated by either a conventional modern external capacitor or by using a Coil For Electro-Magnets then I would imagine there would be an improvement to the Power Factor. Would there not ? Which would equate to an improvement in efficiency I guess.

If the car Tesla made had an AC induction motor, its possible that it was wound bifi, and its possible the coils in the motor were a large component of oscillation.

Mags

• Hero Member
• Posts: 1843
##### Re: Tesla's "COIL FOR ELECTRO-MAGNETS".
« Reply #578 on: January 13, 2014, 11:57:34 AM »
Your right. Just applying dc, especially low voltage, if your not looking for it, you wont see it.

45pf, you better be looking for very high freq initial spike at the time of applying the dc, not just looking at the DC magnetic field after the spike.

@Mags:

What do you mean by "very high freq initial spike". Please look at the drawing, I think you meant a "pulse of short duration"? Do you mean that one should send a short pulse through the pan cake coil? If you mean that, what should be the "astonishing effect"?

Again, I am not criticising, just trying to understand and later on trying to reproduce the alleged effect.

P.S.: A measurement can not be cheap, it can only be correct or incorrect. Why the insults? I am not attacking, I am measuring and then I am being attacked.

• Hero Member
• Posts: 1843
##### Re: Tesla's "COIL FOR ELECTRO-MAGNETS".
« Reply #579 on: January 13, 2014, 12:06:22 PM »
The patent to me looks to be about using frequency. There are several references to it. But I don't see any reference to the field strength when excited by Continuous DC.

The patent is about negating the self inductance of the coil by exciting it at or around it's self resonant frequency, and that by winding it in the way described the self resonant frequency is lower and so easier to achieve.

@Farmhand:

I showed that my bifilar pan cake coil has a lower self resonance frequency than my monofilar pan cake coil (bifilar ~ 4 MHz, monofilar ~ 9 MHz).

From this follows that the bifilar pan cake coil has a higher self capacitance than the monofilar pan cake coil (bifilar ~45 pF, monofilar ~ 9 pF).

The inductance of both my pan cake coils is ~34 µH.

What do you mean by "negating the self inductance of the coil by exciting it at or around it's self resonant frequency"? What is "self inductance"?

I excited both coils around their self resonance frequency and they behave like all coils. (The reactance increases which can be seen as a rise of the Voltage over the coil.)

What should happen in a bifilar pan cake coil when it is excited at its resonance frequency?

What should happen in a monofilar pan cake coil when it is excited at its resonance frequency?

Again, I am not criticising, just trying to understand so that I can measure an alleged effect.

P.S.: I am not off topic, I just measure systematically to separate the known from the unknown.

#### tim123

• Hero Member
• Posts: 509
##### Re: Tesla's "COIL FOR ELECTRO-MAGNETS".
« Reply #580 on: January 13, 2014, 02:30:49 PM »
What is "self inductance"?

It's just inductance. Old terminology perhaps.

I've read the start of the thread. Gyula did a good job of answering the questions I think.

When Tesla's patent was issued - there was no 'standard' - no 50/60Hz grid. It was all new. The generators to drive the electromagnets would have been specially made - and presumably geared to run at the resonant frequency of the coil.

I think a parallel-tank is the best way to run an AC electromagnet - because it minimises power usage when there's no load. Just like an induction heater only draws current when the metal is inserted into the coil... So Tesla's coils make a parallel tank - without needing extra capacitors. It's a clever solution...

• Hero Member
• Posts: 1843
##### Re: Tesla's "COIL FOR ELECTRO-MAGNETS".
« Reply #581 on: January 13, 2014, 04:40:11 PM »

What I can do: pulses, pulse trains

What I can not do: Terahertz diodes, spinning a rotor at radio frequency

So, the magnetic field in normal circumstances (a DC current flows through coil) seems to be identical.

Is there an other magnetic field which is not caused by a DC current?

If an AC current flows through the coil the magnetic field will have one polarity and then the opposite, but it will always be the "normal magnetic field" (just varying in intensity and direction)?

But I give everything the benefit of doubt, but please specify what has to be done to cause the magic? It must be clear and possible!

To certain people: Stop the insults, they do not produce magic in a bifilar coil.

#### synchro1

• Hero Member
• Posts: 4694
##### Re: Tesla's "COIL FOR ELECTRO-MAGNETS".
« Reply #582 on: January 13, 2014, 04:52:17 PM »
Was thinking of the Leedskalnin magnet holder.  If we have a U core with a bar core to close the end, a normal coil will produce a certain amount of field in the core to hold the bar core to the U core.  So if the bifi produces a higher initial field, the cores should lock in more than the normal coil. To find out, there would have to be a very specific and exact way of repeatedly being able to break the bar from the U, to measure the amount of output a pickup coil produces, or use weight to break the magnetic bond. Then there should be a difference in how much weight it takes to break the bond.

Mags

The bond break generates a pulse. RWG demonstrated his Leedskalnin PMH conserving then releasing the
"lock pulse" after two years.  The precise measurement of the return power and comparison to original "Lock pulse" input would be very interesting to explore.

#### synchro1

• Hero Member
• Posts: 4694
##### Re: Tesla's "COIL FOR ELECTRO-MAGNETS".
« Reply #583 on: January 13, 2014, 05:09:40 PM »

What I can do: pulses, pulse trains

What I can not do: Terahertz diodes, spinning a rotor at radio frequency

So, the magnetic field in normal circumstances (a DC current flows through coil) seems to be identical.

Is there an other magnetic field which is not caused by a DC current?

If an AC current flows through the coil the magnetic field will have one polarity and then the opposite, but it will always be the "normal magnetic field" (just varying in intensity and direction)?

But I give everything the benefit of doubt, but please specify what has to be done to cause the magic? It must be clear and possible!

To certain people: Stop the insults, they do not produce magic in a bifilar coil.

Look Conrad, I am an experimenter like you. I need a theory to help explain observed effects. One of those effects is the spontaneous charge in the magnet core bifilar LC tank while standing still. I used the hypothetical "Bloch wall teraherz frequency" theory  as a stepping stone towards better understanding of an overunity effect. The series bifilar has power transfer characteristics that make it a better choice in my view for the kind of power recovery I get from the "Synchro coil". I really can't be sure why it works the way it does. What I do know is that you spent time fashioning a fine prototype to test, and no one is insulting your expert technical skill and craftsmanship. I truly hope we can return to that experiment, fashion a resonant bifilar LC tank with an electrolytic capacitor, perhaps with a pico-farad cap in tandem to, fine tune the bifilar's self capacitance with the tank capacitor, and continue on with the positioning portion of the experiment which started out to be pretty exciting. We're trying to "Pump the core magnets".

#### tim123

• Hero Member
• Posts: 509
##### Re: Tesla's "COIL FOR ELECTRO-MAGNETS".
« Reply #584 on: January 13, 2014, 05:12:21 PM »