Lens's Law what is it ?

[toranarod]

I propose a design of a device to test coils and rotors and RPM.
this should also test the feasibility of the theory.
I need something more than just guessing and testing.
Maybe its all wrong. I have an idea for such a device.


Video 26 - YouTube

this coil achieved a Phase shift of 66 Degrees.

XL 0.926 at 50 Hz R= 0.4 Ohm. Phase 66.63

[toranarod]

I guess I could accept that some current could flow by inertia after a delay or
that there could be a delay in magnetization of a core. I can accept that.

But I can't accept that Lens itself is delayed because there would be no delay in
the induced EMF.

Anyway I think we all agree we are all in this together. And it's time some faster
progress is made by us overall as a movement for change.

I am very happy to have not alienated myself too much with my ramblings in the
different threads, I was afraid I would end up with no friends.
But I faced that fear and I think I prevailed by being so determined.

So onward and upward. I have a lot to learn, and an ever decreasing period
to learn it in. Back to it.

P.S. In those Gray video's anyone notice the open spark gap, the battery
switches, the way the sound gave the impression of the building up of stored
energy at high potential, the way the devices affected the camera and that
there seemed to be a lot of recycling of the energy.

And I say energy because he seemed to be able to draw energy from a
battery utilize a lot of energy in the system and return most of it to a
different battery then swap around repeatedly. Or something like that.

The magnetic's is not so interesting to me as the way the energy is utilized
and and returned to the batteries while as little as possible is dissipated
unnecessarily.

Cheers

You have been a valued contributor to this work and have made friends not the other way around. In my book you are hands on guy. not an armchair Physicist.

[Farmhand]

Thanks Rod, So I was thinking about core saturation and ended up at Wikipedia,

I went looking for info because I had an idea to pulse one cored coil with a lot
of wire in it for say 10 us but have another coil near it and pulse that one
after the first one had had time to magnetize mostly, to near saturation, then
pulse the second coil enough to drive the first into saturation and collapse
them together.

But I can't work out if core saturation increases or decreases inductance yet.

Saturation limits the maximum magnetic fields achievable in ferromagnetic-core electromagnets and transformers to around 2 T, which puts a limit on the minimum size of their cores. This is one reason why high power utility transformers are so large.
In electronic circuits, transformers and inductors with ferromagnetic cores operate nonlinearly when the current through them is large enough to drive their core materials into saturation. This means that their inductance and other properties vary with changes in drive current. In linear circuits this is usually considered an unwanted departure from ideal behavior. When AC signals are applied, this nonlinearity can cause the generation of harmonics and intermodulation distortion. To prevent this, the level of signals applied to iron core inductors must be limited so they don't saturate. To lower its effects, an air gap is created in some kinds of transformer cores.[6]
On the other hand, saturation is exploited in some electronic devices. Saturation is employed to limit current in saturable-core transformers, used in arc welding. When the primary current exceeds a certain value, the core is pushed into its saturation region, limiting further increases in secondary current. In a more sophisticated application, saturable core inductors and magnetic amplifiers use a DC current through a separate winding to control an inductor's impedance. Varying the current in the control winding moves the operating point up and down in the saturation curve, controlling the AC current through the inductor. These are used in variable fluorescent light ballasts, and power control systems.

[Farmhand]

wow, I think my first concept drawing would resemble one of these things.

I remember Cifta gave some links for these things and some other links too. I'll
have to revisit them when I remember where the links he gave are (which thread).

Magnetic amplifier - Wikipedia, the free encyclopedia

Principle of operation

A saturable reactor, illustrating the principle of a magnetic amplifier
Visually a mag amp device may resemble a transformer but the operating principle is quite different from a transformer - essentially the mag amp is a saturable reactor. It makes use of magnetic saturation of the core, a non-linear property of a certain class of transformer cores. For controlled saturation characteristics the magnetic amplifier employs core materials that have been designed to have a specific B-H curve shape that is highly rectangular, in contrast to the slowly-tapering B-H curve of softly saturating core materials that are often used in normal transformers.
The typical magnetic amplifier consists of two physically separate but similar transformer magnetic cores, each of which has two windings - a control winding and an AC winding. A small DC current from a low impedance source is fed into the series-connected control windings. The AC windings may be connected either in series or in parallel, the configurations resulting in different types of mag amps. The amount of control current fed into the control winding sets the point in the AC winding waveform at which either core will saturate. In saturation, the AC winding on the saturated core will go from a high impedance state ("off") into a very low impedance state ("on") - that is, the control current controls at which voltage the mag amp switches "on".
A relatively small DC current on the control winding is able to control or switch large AC currents on the AC windings. This results in current amplification.

..

[Shadesz]

i will do that now give me a few hours to set up and get data.
how do you suggest i take the measurements? can you do quick drawing.
i like to know how you think it should work. help me see your point of view.

Sorry I was away from my computer last night. I would love to draw it up for you. I will also demonstrate why I think a pickup coil doesn't act like an inductor. I have some quick house chores and homework but I should be able to get to it within 4 or so hours.

[Shadesz]

I propose a design of a device to test coils and rotors and RPM.
this should also test the feasibility of the theory.
I need something more than just guessing and testing.
Maybe its all wrong. I have an idea for such a device.


Video 26 - YouTube

this coil achieved a Phase shift of 66 Degrees.

XL 0.926 at 50 Hz R= 0.4 Ohm. Phase 66.63

It would be interesting to see your idea. I'll draw up my idea as well.

The device could help us learn how to design the effect in our pickup circuits if we prove that it is valuable enough.

When I get some time later today I will see if the simulator matches the numbers you achieved in real life. If it did, I think we can actually just use a simulator. I'll expand later.

[Shadesz]

You have been a valued contributor to this work and have made friends not the other way around. In my book you are hands on guy. not an armchair Physicist.

Farmhand, I agree with Rod. You have done well. I will share that there is a reason I am using this forum and not the others. It just seems to have more of a teamwork and mutual respect crowd here. Less trolls, and more mature confrontation.

Rod,
Sometimes I feel like I am a computer chair physicist. I'll get there slowly (test equipment, etc). I am still young. I appreciate your willingness to share.

[Shadesz]

This is a copy of a post I just made in Rod's thread.

Farmhand, according to this, you are exactly right. The phenomenon we are talking about isn't delayed lenz law. These professors/scientists suggest it is more to do with Faraday’s Law. Good job. Now to get the OU community to accept a proper term...

Hey everyone,

I found a few publications that investigate this levitating ring phenomenon. They suggest that claims referring to it simply being lenz law and/or phase shift are not correct. They suggest something else is happening. These publications are only 4 years old.

I found some of them at my University's Online Library. Because they are published in scientific journals I cannot post the full articles here, unless I find them freely distributed through a google search..


Here is one

The popular physics demonstration experiment known as Thomson's Jumping Ring (JR) has been variously explained as a simple example of Lenz's law, or as the result of a phase shift of the ring current relative to the induced emf. The failure of the first-quadrant Lenz's law explanation is shown by the time the ring takes to jump and by levitation. A method is given for measuring the phase shift with results for aluminum and brass rings.

And another (this one you can download)

A popular demonstration relating to induced
currents is the jumping ring experiment. Here,
a conducting non-magnetic ring is placed over
the extended vertical core of a solenoid or
demountable transformer. When ac power is
applied to the solenoid the ring is thrown off or
held in a state of levitation (from whichever limb
it is placed on). A good practical description
of this may be found in an article by Ford and
Sullivan [1], and there is a more analytical article
by Sumner and Thakkrar [2]. An explanation
of this effect that is sometimes offered is that it
happens because the induced current in the ring
obeys Lenz’s law, and as the fields are opposing
the ring will be thrown off [3, 4].

Summary
Lenz’s law alone cannot be used to explain the
behaviour of a jumping or levitating ring. The
correct explanation requires an application of
Faraday’s law together with circuit analysis of the
system. This then leads to the reasons for selecting
an aluminium ring of a particular size.

Note that this article references others that explain the phenomenon. They would be good to look up as well.

[Farmhand]

Hi Guys, I was thinking about induced EMF and the current delay. And it occurred
to me that in an induction motor with closed coils on the armature if the field
coils were made to be high impedance and run at high frequency any delayed
"Lens current" effects should be observable right there in an induction motor.

In my opinion any reduction in the amount of current that can flow will make
the motor slower and less powerful as a result of the reduced current flow..

I think Lens current is just like VAR it is not even real current I think it is only
imaginary current or a force. Just like "VAR" or reactive power.

It seems to me it is BEMF and is only present when there is a greater EMF to oppose.

I've got a whole heap of farm work to do so I can only experiment when I get
time for the next few days.

Cheers

[toranarod]

Sorry I was away from my computer last night. I would love to draw it up for you. I will also demonstrate why I think a pickup coil doesn't act like an inductor. I have some quick house chores and homework but I should be able to get to it within 4 or so hours.

there are some many test and experiments to do I am booked on the bench for the next year.
Then there is house chores to do. Did Nikola Tesla have house work?

[toranarod]

This is a copy of a post I just made in Rod's thread.

Farmhand, according to this, you are exactly right. The phenomenon we are talking about isn't delayed lenz law. These professors/scientists suggest it is more to do with Faraday’s Law. Good job. Now to get the OU community to accept a proper term...

Hey everyone,

I found a few publications that investigate this levitating ring phenomenon. They suggest that claims referring to it simply being lenz law and/or phase shift are not correct. They suggest something else is happening. These publications are only 4 years old.

I found some of them at my University's Online Library. Because they are published in scientific journals I cannot post the full articles here, unless I find them freely distributed through a google search..


Here is one


And another (this one you can download)

Note that this article references others that explain the phenomenon. They would be good to look up as well.

Great PDF
Thanks
maybe one of the reasons acceleration under load is so hard to get just right is because its a combination of many techniques all accumulating at the right time.

[Farmhand]

With some more digging I found this. I think some of the text related to this
motor can tell us some things.

From the IRWNT book. I guess I must Quote it in text.

Page 20, but the section starts before that. On page 19 is the microwave
oven fan motor I have. Same thing.

in Fig. 14, are sufficient, but a greater number may be advantageously
employed. It results from this disposition that when
the poles of the ring are shifted, currents are generated in the
closed armature coils. These currents are the most intense at or
near the points of the greatest density of the lines of force, and
their effect is to produce poles upon the armature at right angles
to those of the ring, at least theoretically so ; and since this action
is entirely independent of the speed that is, as far as the location
of the poles is concerned a continuous pull is exerted upon the
periphery of the armature. In many respects these motors are
similar to the continuous current motors. If load is put on, the
speed, and also the resistance of the motor, is diminished and
more current is made to pass through the energizing coils, thus
increasing the effort. Upon the load being taken off, the
counter-electromotive force increases and less current passes
through the primary or energizing coils. Without any load the
speed is very nearly equal to that of the shifting poles of the
iield magnet.

A characteristic feature of motors of this kind is their property
of being very rapidly reversed. This follows from the peculiar
action of the motor. Suppose the armature to be rotating and
the direction of rotation of the poles to be reversed. The apparatus
then represents a dynamo machine, the power to drive this
machine being the momentum stored up in the armature and its
speed being the sum of the speeds of the armature and the
poles.
If we now consider that the power to drive such a dynamo'
FIG. 18. FIG. 19. FIG. 20. FIG. 21.
would be very nearly proportional to the third power of the
speed, for that reason alone the armature should be quickly reversed.
But simultaneously with the reversal another element is
brought into action, namely, as the movement of the poles with
respect to the armature is reversed, the motor acts like a transformer
in which the resistance of the secondary circuit would be
abnormally diminished by producing in this circuit an additional
electromotive force. Owing to these causes the reversal is instantaneous.

Uploaded with ImageShack.us

I think I might try to build some kind of motor like this for experimenting.
A small motor could use a toroidal transformer core. and Maybe an existing
Armature from a fan motor or something, or make one or rewind one.

No neo's required. Just wire. I think I have a fairly good understanding of
what he is saying there now.

EDIT: Actually it appears that shorted (or nearly) generator coils would
constitute a crude reverse induction motor. And current flow would be
affected unless the field magnets (rotor magnets) was at a steady state speed. In a steady state speed no extra currents are developed.

It is starting to seem that way to me when I look at it.

Cheers

[Farmhand]

I guess what I want to do is go back one step and look at the motor driving
the generator. Trying to get as much rotary effort as possible as efficiently as
possible to start with. I think I should be able to arrange some kind of AC
arrangement similar to the Switchback DC motor setup I had going a while
ago, but more compact and integrated. By making the transformer and motor
field coils as one.

When the rotor is loaded the motor just recycles more current and power
remains fairly constant. Very small losses. I say drain Not Gain.


Switchback setup
Switchback Drive.wmv - YouTube

Waveform of transformer on scope.
Motor Drive Waveform.wmv - YouTube

Cheers

[Farmhand]

Hey rod I think this section of the IRWNT book might interest you.

The part I think will interest us starts at page 15 chapter III (3)

With this Gem.

Hahaha by combined action of the source currents and of induced currents.

The second way.

These motors may be operated in three different ways : 1. By
the alternate currents of the source only. 2. By a combined action
of these and of induced currents. 3. By the joint action of
alternate and continuous currents.

This type of motor seems to be very good at using the currents induced by its own action.

To facilitate the starting, the disc may be provided with a coil
closed upon itself. The advantage secured by such a coil is evident.
On the start the currents set up in the coil strongly energize the disc and increase the attraction exerted upon the same by
the ring, and currents being generated in the coil as long as the
speed of the armature is inferior to that of the poles, considerable
work may be performed by such a motor even if the speed
be below normal. The intensity of the poles being constant, no
currents will be generated in the coil when the motor is turning
at its normal speed.
Instead of closing the coil upon itself, its ends may be connected
to two insulated sliding rings, and a continuous current supplied
to these from a suitable generator. The proper way to start such
a motor is to close the coil upon itself until the normal speed is
reached, or nearly so, and then turn on the continuous current.
If the disc be very strongly energized by a continuous
current the motor may not be able to start, but if it be weakly
energized, or generally so that the magnetizing eifect of the ring
is preponderating, it will start and reach the normal speed. Such
a motor will maintain absolutely the same speed at all loads. It
has also been found that if the motive power of the generator is
not excessive, by checking the motor the speed of the generator is
diminished in synchronism with that of the motor. It is characteristic
of this form of motor that it cannot be reversed by reversing
the continuous current through the coil.