Author Topic: Tesla's "COIL FOR ELECTRO-MAGNETS". (Read 508903 times)

Magluvin · « **Reply #105 on:** May 17, 2013, 02:20:06 AM »

Quote from: TinselKoala on May 16, 2013, 12:16:14 PM

Kenneth Corum and James Corum.

There is a lot of misunderstanding and even disinformation about Tesla, Tesla coils, and the Tesla bifilar winding patent, and series bf vs. parallel bf vs. ordinary winding, etc. The Corums get it right, but their work is highly technical and hard to find in "condensed" form.

Tesla wanted low resonant frequencies with as little wire as possible and without the expense and difficulty of large and expensive and dangerous HV capacitors. A precisely constructed and tuned, flat pancake "series bifilar" coil's greatly increased self-capacitance allowed him to achieve that goal. His purpose was to attain very fast (for those days) rise and fall times in the primary coils of his power systems. The faster the transitions in the primary, the greater the voltage induced in the secondary. This is why, for example, modern square-wave SSTC drivers are able to pump up such high secondary voltages without HV in the primary or spark gaps: the fast rise and fall times of the pulses is accomplished by the modern semiconductors and the driver circuitry.
The "ideal" Tesla coil/power transmission system might consist of a low-frequency secondary, driven by a Tesla bifilar primary, using no tank capacitor but only the coil's self-capacitance, to attain a low resonant frequency of its own, matched to the secondary. Such a coil would have to be physically large and very precisely constructed, and it's doubtful that even modern semis, like large IGBTs, would be able to handle the stress of driving it at high power levels.

There are winding schemes that have "special" effects on coils. I think these do things like change the ratio of DC resistance to the inductance attained in the coil. Take a look at some old radio RF coils or chokes. You will see all kinds of mysterious winding patterns. Even my simple loopsticks have a dual coil, separated by a specific gap, and each coil is wound in a herringbone crossover pattern, very neatly, with cotton-covered, enamelled Litz wire. You can be sure that the makers would not have bothered to do this if a simple single, random-wound coil of the same amount of wire would 'do the trick'.

"There is a lot of misunderstanding and even disinformation about Tesla, Tesla coils, and the Tesla bifilar winding patent, and series bf vs. parallel bf vs. ordinary winding, etc."

"His purpose was to attain very fast (for those days) rise and fall times in the primary coils of his power systems."

"The faster the transitions in the primary, the greater the voltage induced in the secondary."

"Even my simple loopsticks have a dual coil, separated by a specific gap, and each coil is wound in a herringbone crossover pattern, very neatly, with cotton-covered, enamelled Litz wire."

I remember these. Some with a tube core with an adjustable core in the vertical tube and some with 2 coils like you say but spaced apart. Found a pic shown below. Its not exactly as I remember. I had an old AM SW MW radio when I was a kid that I found in a building of an old abandoned park from the early 1900s. The wood case was lierally disintegrated. But I got that thing to work.

It had the tuning eye tube. Remember those?

I loved that radio. Learned a lot from it. Memories.

Here is a site that talks about different coils and why.

English on the left. Deutsch on the right.

http://www.oldradioworld.de/gollum/hcoils.htm

"driven by a Tesla bifilar primary, using no tank capacitor but only the coil's self-capacitance"

Hmm, just put the spark gap across the input leads? Nice.

Thanks

Mags

Magluvin · « **Reply #106 on:** May 17, 2013, 02:42:32 AM »

Quote from: Farmhand on May 16, 2013, 03:32:47 PM

Not using one side of the magnetic field of a very low loss inductor will not waste much energy Mags, at most it will waste some space I think.

No no. what I mean is that other side of the coil , for imaginary purposes, can drive another rotor without speed drop of the first rotor. Geddit?

So if you had a core that directs the N and S of the coil to just one rotor where the N of the coil is pulling on the rotor magnet and the S of the coil is pushing at the same time, you will get more motive force on the rotor. That was all I was suggesting.

Mags

Magluvin · « **Reply #107 on:** May 17, 2013, 05:57:35 AM »

Quote from: MileHigh on May 16, 2013, 03:46:28 AM

Ignoring the capacitance of the coil or not ignoring the capacitance of the coil depends on what you are doing. If you are using the coil as a drive coil for a pulse motor or as a pick-up coil for a spinning rotor then yes, you can ignore the capacitance. Remember I crunched Farmhand's measurements on one of his coils and noted that the capacitive energy in the coil was 1/17,000th of the inductive energy in the coil under typical conditions?

If you are talking about a small coil that's on a PCB that's part of a very high frequency analog circuit design, then you probably have to consider the capacitance of the coil. Nobody on the forums is doing very high frequency analog circuit design.

What do you and Farmhand and possibly others really mean when you say "neutralizes" in this context?

It goes back to the theme of my posting. You want to try to direct your energies and your time to where it counts. You mechanic says to you that you should check/change your oil every 3000 miles. Most people might only change it every 6000 miles and not check it at all and just change their oil three or four times a year. So do you stop your car every 100 miles and get out, check the old level and smell it and contemplate changing it? Is that good use of your time?

In a way you can say that there are kind of "electronic fetishes" that run rampant in the free energy forums and they waste a lot of people's time. Worrying about the minuscule transient capacitance in a pulse motor drive coil would be one of them. Some people have battery fetishes where they believe their circuit has to be connected to a battery to work properly and a regular bench power supply will "kill the effect." Several years ago people played with car ignition coils and they noticed that their CFL lights light up brighter when they made a connection to earth ground. So there was a crazy belief that "power comes up from the ground." That one is still running rampant.

MileHigh

"What do you and Farmhand and possibly others really mean when you say "neutralizes" in this context?"

And possibly others? lol Tesla had the patent and he said it. What do you think it means in your context?

"In a way you can say that there are kind of "electronic fetishes" that run rampant in the free energy forums and they waste a lot of people's time. Worrying about the minuscule transient capacitance in a pulse motor drive coil would be one of them."

Fetishes?

Why dont you top it off with a used condom across the page. That would be a huge deterrent.

You really dont like the idea that people work with this coil do you?

This is what I like about the idea of the coil reacting quicker for a pulse motor. There will be more of an impulse than a gradual climb in current flow when the coil is being pulsed. We are talking 'pulse' motors. A quick pulse has more impact, impulse. It pops, no waiting period, no mooshy mooshy. Like using a small sledge hammer vs a rubber mallet of the same size.
Another thing is, lets say we have a simple pulse motor. 12v batt, normal coil, rotor with magnets and a reed switch. When we close the reed, it will take some time for the field to build due to impedance. And when it finally peaks or even sustains peak for the duration of the switch closure and the reed releases and waits for the next mag pass. But once we get to higher revolutions, the pulse times will be shorter with less time for the field to build. But the fast acting bifi will be able to react more quickly with more controlled on and off times and better high rpm performance.

Now we try something different. We use a large inductor and a diode added to the circuit. What we are going to do is use the reed to charge up the new large inductor and when the reed releases, let the collapse current of the large inductor dump into the motor driver coil to run the motor. But oh, the motor driver coil will not accept the collapse current due to impedance so the reed burns instead.

But if the motor driver coil is a bifi, even a big one, it will accept that collapse current, not the 'norm', which will charge that tiny capacitance of the bifi to possibly many hundreds of volts.

and

This is an idea I have from understanding the workings of the 'Igniter for Gas Engines' and the 'Coil for Electro-magnets', as to what is described, where we use the large inductor efficiency from the igniter to charge the bifi for a pulse at a higher potential than the batt input. We are charging the bifi capacitance with an inductor not from the battery directly, or we would lose half the energy used from the battery to charge the cap directly.

This is a much different way of doing things than we are used to.

And its way more fun than building a universal motor. Been there done that been done. Lets move on to new things.

Standing still will get you nowhere.

Mags

MileHigh · « **Reply #108 on:** May 17, 2013, 06:52:10 AM »

I am just catching up! No time to read other thread.

Farmhand:

I can never remember which is which so I had to check. Looking up LC circuit yet again....

Wiki quotes....

The charge flows back and forth between the plates of the capacitor, through the inductor. The energy oscillates back and forth between the capacitor and the inductor until (if not replenished by power from an external circuit) internal resistance makes the oscillations die out. Its action, known mathematically as a harmonic oscillator, is similar to a pendulum swinging back and forth, or water sloshing back and forth in a tank. For this reason the circuit is also called a tank circuit. The oscillation frequency is determined by the capacitance and inductance values. In typical tuned circuits in electronic equipment the oscillations are very fast, thousands to millions of times per second.

In a series configuration, X_C and X_L cancel each other out. In real, rather than idealised components the current is opposed, mostly by the resistance of the coil windings. Thus, the current supplied to a series resonant circuit is a maximum at resonance.

The parallel LC circuit connected in series with a load will act as band-stop filter having infinite impedance at the resonant frequency of the LC circuit. The parallel LC circuit connected in parallel with a load will act as band-pass filter.

.......

I view a self-resonating coil as a parallel LC circuit. Which would mean it blocks a signal passing through it at the resonant frequency. I am just not sure how you are applying whatever resonance concepts to your circuit or motor. If either form of resonance is associated with "neutralizing the self inductance" keep in mind we are talking about a pure sinusoidal excitation waveform. You don't normally see a pure sinusoid and deviations from the pure sinusoid mean that there is other harmonic content in the waveform that is not in resonance and does its own thing.

TK:

I think the fancy coil patterns in old radios are related to their roll-off frequencies and stuff like that. So indeed, that's a case of where it's by design for a particular purpose. It also might not be true, and it's just a manufacturing technique. I really don't know.

Pulling out the big guns, this guy is great and he really knows his radio circuits. Radios are all about resonant circuits. He also teaches a lot about electronics. Plus, it's simply fun to see how things were designed and manufactured so long ago:

http://www.youtube.com/user/AllAmericanFiveRadio/videos?view=0&flow=grid

He does respond to questions in case someone wants to ask him about the herringbone coils.

Let me again share some thoughts about a self-resonating coil vs. an LC resonator, i.e.; two separate components. The self-resonating coil is a kind of kludge. You don't have a regular, ordered exchange between stored capacitive energy and stored magnetic energy. They are intermixed with each other and if real push came to shove you would need a supercomputer crunching away to model it. On the other hand, a LC resonator is smooth like butter. The capacitor discharges into the coil, then the coil discharges into the capacitor. The current flows back and forth, the voltage goes up and down. That transfer of energy can be visualized as a rotating vector. It's the way it's supposed to work. In comparison to that a self-resonating coil is a different animal. That's what I envision in my head.

Now realistically, if you scoped a self-resonating coil you would probably see a voltage waveform that was a sine wave across the ends of the coil. At the same time it can only store a tiny fraction of the of energy of a comparable LC circuit - an inductor mated with a capacitor of comparable size. I realize it's all relative to what you want to do. I am just not sure what that is. Nonetheless, a self-resonating coil is like a short faint wisp of stored energy at a crazy high frequency that disappears quickly compared to making a real loud and ringing LC resonator bell made with the same coil.

MileHigh

MileHigh · « **Reply #109 on:** May 17, 2013, 07:57:13 AM »

Magluvin:

Quote

This is what I like about the idea of the coil reacting quicker for a pulse motor. There will be more of an impulse than a gradual climb in current flow when the coil is being pulsed. We are talking 'pulse' motors. A quick pulse has more impact, impulse. It pops, no waiting period, no mooshy mooshy. Like using a small sledge hammer vs a rubber mallet of the same size.
Another thing is, lets say we have a simple pulse motor. 12v batt, normal coil, rotor with magnets and a reed switch. When we close the reed, it will take some time for the field to build due to impedance. And when it finally peaks or even sustains peak for the duration of the switch closure and the reed releases and waits for the next mag pass. But once we get to higher revolutions, the pulse times will be shorter with less time for the field to build. But the fast acting bifi will be able to react more quickly with more controlled on and off times and better high rpm performance.

The only way to get a faster reaction out of the coil is to increase the drive voltage. The coil integrates voltage with respect to time to yield current. How do you get a flywheel to spin up faster? More torque.

Without increasing the voltage your impulse might charge some capacitance. That will not give the coil any push against the rotor. The only way to get the coil to push is to have it generate a magnetic field which leads back to the question of the drive voltage over time.

Your point about the higher RPM meaning less switch-on time and hence lower maximum current through the coil is dead on. It's all part of the pulse motor finding a quiescent speed. You can try to optimize stuff like Farmhand is doing and that's finding a higher quiescent speed.

The parameters are the amount of inductance, the switch timing, and the drive voltage. Faster RPM by default limits the switch-on time, so you can experiment with the amount of inductance and the drive voltage to pump more power into the coil which pumps more power into the rotor to balance out the air and bearing friction. Hence my fantasy of slowly cranking up the voltage to see what fails first. Push the sucker past its design limits.

So the inductance is still a wall that you have to push against, series bifilar or not.

Quote

What we are going to do is use the reed to charge up the new large inductor and when the reed releases, let the collapse current of the large inductor dump into the motor driver coil to run the motor. But oh, the motor driver coil will not accept the collapse current due to impedance so the reed burns instead.

I will rephrase that as a question: What happens when Coil A with current A discharges into Coil B with current B?

Quote

But if the motor driver coil is a bifi, even a big one, it will accept that collapse current, not the 'norm', which will charge that tiny capacitance of the bifi to possibly many hundreds of volts.

Exactly, but that won't push on the rotor! But what happens after that and how does that relate to the question above?

MileHigh

Farmhand · « **Reply #110 on:** May 17, 2013, 12:17:38 PM »

Quote from: MileHigh on May 17, 2013, 06:52:10 AM

Farmhand:

Wiki quotes....

The charge flows back and forth between the plates of the capacitor, through the inductor. The energy oscillates back and forth between the capacitor and the inductor until (if not replenished by power from an external circuit) internal resistance makes the oscillations die out. Its action, known mathematically as a harmonic oscillator, is similar to a pendulum swinging back and forth, or water sloshing back and forth in a tank. For this reason the circuit is also called a tank circuit. The oscillation frequency is determined by the capacitance and inductance values. In typical tuned circuits in electronic equipment the oscillations are very fast, thousands to millions of times per second.

In a series configuration, X_C and X_L cancel each other out. In real, rather than idealised components the current is opposed, mostly by the resistance of the coil windings. Thus, the current supplied to a series resonant circuit is a maximum at resonance.

The parallel LC circuit connected in series with a load will act as band-stop filter having infinite impedance at the resonant frequency of the LC circuit. The parallel LC circuit connected in parallel with a load will act as band-pass filter.

.......

I view a self-resonating coil as a parallel LC circuit. Which would mean it blocks a signal passing through it at the resonant frequency. I am just not sure how you are applying whatever resonance concepts to your circuit or motor. If either form of resonance is associated with "neutralizing the self inductance" keep in mind we are talking about a pure sinusoidal excitation waveform. You don't normally see a pure sinusoid and deviations from the pure sinusoid mean that there is other harmonic content in the waveform that is not in resonance and does its own thing.

I do understand what you are saying in a layman's way, and I have read that series resonance means no resistance and parallel resonance means infinite resistance, but I don't buy it. Simply because if a condition of parallel resonance actually meant infinite resistance we would never see it because it would be impossible, unattainable.

And likewise no resistance would mean superconductor current from very low voltages and we don't see that.

If a parallel resonance condition created an infinite resistance then how can current flow to cause it. When we tune a crystal radio receiver output coil to parallel resonance at the frequency we want to hear it works. Maybe at some point there is infinite resistance but at what point. Can you show us what infinite resistance looks like in a circuit tuned to parallel resonance ?

Bottom line is it sounds impossible to me.

When we tune a Tesla coil primary to parallel resonance we see to begin with when there is no resonance the input is very small, not much power can be input without resonance, but when we get the primary and secondary tuned to each other the primary can have parallel resonance or very close to it and much more power can be input.

Maybe not actually at full resonance but close to it. Thing is without the parallel resonance on the Tesla coil primary less power can be input. How can more resistance mean easier current flow ?

EDIT: The control circuit in these two video's is a fixed frequency CMOS logic gate oscillator with a fixed pulse width and it is not changed so the exciting pulses are unchanged, the only change in the video is tuning the primary to parallel resonance. JUst ignore the ringing on the gate I fixed that I think from memory.

In the video below when I adjust the primary capacitor to parallel resonance the input increases a lot and the secondary resonates much stronger. How is that possible with infinite resistance ?
http://www.youtube.com/watch?v=jJZoENDhero

If I tune away from resonance the output and input is virtually nothing.
http://www.youtube.com/watch?v=lEX9MKBhVZk

So you can see why I don't buy it.

Cheers

Farmhand · « **Reply #111 on:** May 17, 2013, 12:30:36 PM »

Quote from: Magluvin on May 17, 2013, 02:42:32 AM

No no. what I mean is that other side of the coil , for imaginary purposes, can drive another rotor without speed drop of the first rotor. Geddit? So if you had a core that directs the N and S of the coil to just one rotor where the N of the coil is pulling on the rotor magnet and the S of the coil is pushing at the same time, you will get more motive force on the rotor. That was all I was suggesting.

Mags

Mags I don't think that is the case, my experiments tell me that if the coil pushes a rotor from both ends less energy will be recovered from the collapsing magnetic field because more energy is imparted to the second rotor. So basically I think if the input is fixed voltage and current then driving a second rotor will slow down the first one or return less energy from the magnetic filed collapse, if the input power is not fixed then I think the input power would increase.

Bottom line is I don't think it is free work to drive a rotor with a coil. How can it be ? How could the rotor get energy if not from the coil ? And if it gets energy from the coil then the coils energy must decrease or the input must increase. Seems like good logic to me.

I can actually see the voltage in my charging cap increase when I move the charging coil away from the rotor and the cap voltage decreases when I move it in to speed up the rotor. It's pretty conclusive to me when the coil drives a rotor energy is imparted to the rotor from the coil and the coils magnetic field energy decreases. As it must, or the rotor would get no energy and not turn.

Just what I'm seeing, I've got video of that.

Cheers

Magluvin · « **Reply #112 on:** May 17, 2013, 02:43:28 PM »

Quote from: Farmhand on May 17, 2013, 12:30:36 PM

Mags I don't think that is the case, my experiments tell me that if the coil pushes a rotor from both ends less energy will be recovered from the collapsing magnetic field because more energy is imparted to the second rotor. So basically I think if the input is fixed voltage and current then driving a second rotor will slow down the first one or return less energy from the magnetic filed collapse, if the input power is not fixed then I think the input power would increase.

Bottom line is I don't think it is free work to drive a rotor with a coil. How can it be ? How could the rotor get energy if not from the coil ? And if it gets energy from the coil then the coils energy must decrease or the input must increase. Seems like good logic to me.

I can actually see the voltage in my charging cap increase when I move the charging coil away from the rotor and the cap voltage decreases when I move it in to speed up the rotor. It's pretty conclusive to me when the coil drives a rotor energy is imparted to the rotor from the coil and the coils magnetic field energy decreases. As it must, or the rotor would get no energy and not turn.

Just what I'm seeing, I've got video of that.

Cheers

Oh, then why build it as a motor at all if the 'object' to collect collapse currents? You could just pulse the coil alone and do that. Or are you just trying to split the difference and get some motive force and some collapse gathering in what your saying?

From what I have found is that if im driving a rotor with an air core while collecting collapse currents, when I introduce a core to the coil my rotor is faster and I get increased collapse output. The core helps control, concentrate and direct the coils field increasing the coils ability to do both better at the same time.

Maybe what you are doing and your goals are different somehow.

Mags

Magluvin · « **Reply #113 on:** May 17, 2013, 03:06:11 PM »

Quote from: MileHigh on May 17, 2013, 07:57:13 AM

Magluvin:

The only way to get a faster reaction out of the coil is to increase the drive voltage. The coil integrates voltage with respect to time to yield current. How do you get a flywheel to spin up faster? More torque.

Without increasing the voltage your impulse might charge some capacitance. That will not give the coil any push against the rotor. The only way to get the coil to push is to have it generate a magnetic field which leads back to the question of the drive voltage over time.

Your point about the higher RPM meaning less switch-on time and hence lower maximum current through the coil is dead on. It's all part of the pulse motor finding a quiescent speed. You can try to optimize stuff like Farmhand is doing and that's finding a higher quiescent speed.

The parameters are the amount of inductance, the switch timing, and the drive voltage. Faster RPM by default limits the switch-on time, so you can experiment with the amount of inductance and the drive voltage to pump more power into the coil which pumps more power into the rotor to balance out the air and bearing friction. Hence my fantasy of slowly cranking up the voltage to see what fails first. Push the sucker past its design limits.

So the inductance is still a wall that you have to push against, series bifilar or not.

I will rephrase that as a question: What happens when Coil A with current A discharges into Coil B with current B?

Exactly, but that won't push on the rotor! But what happens after that and how does that relate to the question above?

MileHigh

"The only way to get a faster reaction out of the coil is to increase the drive voltage."

You are talking about a normal coil. You ignore what Tesla, TK(above) and I have been saying about the bifi coil. You just revert back to there is only inductance in the coil. You deny that anything is different in the bifi coil, yet never built one nor tested one as I read it.

"Without increasing the voltage your impulse might charge some capacitance. That will not give the coil any push against the rotor."

So what level of voltage does it take to give 'any' push to the rotor? You are not making any sense. People run motors off of less than 1.5v and up.

"So the inductance is still a wall that you have to push against, series bifilar or not."

Again you are ignoring and refuse to accept what we are discussing in this thread and never built or experienced a bifi coil. If the bifi were made to oscillate at say 1khz, the pulsing that coil with a 1ms pulse would be accepted into the coil very well as it is in the freq range.

"I will rephrase that as a question: What happens when Coil A with current A discharges into Coil B with current B?"

Again, and I went over this in my post, you are ignoring facts about the bifi operation because you just cant get past the idea that the bifi is any different than a normal coil. There really isnt much sense in me trying to describe it to you any further as its clear you are in denial and full rejection of what is being stated in the patent, or you are just not understanding it. I, or anyone can only go so far to break down your wall of disbelief.

Mags

Farmhand · « **Reply #114 on:** May 17, 2013, 07:16:04 PM »

Quote from: Magluvin on May 17, 2013, 02:43:28 PM

Oh, then why build it as a motor at all if the 'object' to collect collapse currents? You could just pulse the coil alone and do that. Or are you just trying to split the difference and get some motive force and some collapse gathering in what your saying?

From what I have found is that if im driving a rotor with an air core while collecting collapse currents, when I introduce a core to the coil my rotor is faster and I get increased collapse output. The core helps control, concentrate and direct the coils field increasing the coils ability to do both better at the same time.

Maybe what you are doing and your goals are different somehow.

Mags

Mags, It doesn't have anything to do with collecting the magnetic field energy, it just proves to me that driving a rotor uses some of the magnetic field energy.

When I see that when the charging coil of a resonant charging circuit is helping to drive the rotor is producing less voltage into the charging capacitor than when it doesn't help drive the rotor that is conclusive proof to me that using both ends will reduce the magnetic field energy more than using one end and so the first rotor will get a weaker field for the same input power. It makes no difference if the collapse is collected or not afterwards, driving a rotor takes energy from the field so driving two will take some away from the first.

It's an easy experiment to do and see the actual result.

In case you haven't noticed or don't remember I'm returning the unused magnetic field energy to be reused mainly. So what the rotor uses and losses is the input.

I'm designing and testing a motor to try to make best use of one switching phase and the collapse of magnetic fields to produce torque in a pulse motor.

What is your objective ? I was responding to you saying not using both ends is wasteful, it isn't necessarily wasteful. A boost converter can be well over 90 % efficient and it uses no ends of the coil core. It's solid state. Waste is losses and there are not losses involved in not using one end of a coil if the remaining magnetic field energy is utilized.

Why have a pulse motor and not collect or reuse the remaining energy of the magnetic field to cause more current.

Remember I first doubted the current from the collapse went through the coil, and did the comparison between a snubbed motor coil and one that allows an orderly field collapse
and when snubbed the coil current stops immediately. This means the coil stops pushing the rotor suddenly rather than tapering off the push and pulling the next opposite polarity magnet.

I'm trying to build a more efficient, more powerful and useful form of pulse motor. So far it looks good.

Cheers

MileHigh · « **Reply #115 on:** May 17, 2013, 11:11:45 PM »

Farmhand:

Quote

I do understand what you are saying in a layman's way, and I have read that series resonance means no resistance and parallel resonance means infinite resistance, but I don't buy it. Simply because if a condition of parallel resonance actually meant infinite resistance we would never see it because it would be impossible, unattainable.

You will recall that TK recently did the coil resonance tests. If you look at Itsusable's videos he also did some coil resonance tests several months ago. You have the signal generator output going to the resistor going to the coil. When you hit the coil's self-resonance point you see maximum amplitude across the coil. So what does that suggest? There is a part of that test that I haven't seen done to my recollection. That's to check the voltage across the resistor. When you think about it, checking the voltage across the resistor is telling you how much current is flowing through the coil at resonance. Sounds like a good test but you have to use a real sine wave.

What it suggests is that if you have maximum voltage across the coil at resonance, then the coil is sustaining the most or all of the voltage drop from the signal source. Therefore you would expect that very little or none of the voltage drop will be sustained across the resistor. Therefore just from the fact that you know the signal generator is producing a sine wave and the self-resonating coil is producing a similar sine wave, you can conclude that the LC resonator is at maximum impedance. i.e.; it's acting like a parallel LC resonator at very high impedance and blocking the current flow. You are welcome to check for yourself.

What that means is that in parallel LC resonance the LC resonator is meeting the driving signal source volt for volt. The signal source wants to put out 3 volts, and the LC resonator is also putting out 3 volts. So the LC resonator is "pushing back" against the signal generator and no current flows.

Now, is this happening on your bench in your setup? I don't know and I am not sure which schematic or configuration you are using today, etc, etc. But if you do the basic test and confirm what I say, that would be interesting. To be more practical, I can suggest that you try it with a real parallel LC resonator also. At resonance you should see zero or near-zero current flow.

Then hopefully you can apply this knowledge to what you are doing. The first thing that comes to mind is that if you put a resistive load in parallel with a parallel LC resonator, and feed it power from a signal generator through a resistor, will that actually give you some advantages in driving a resistive load across the LC resonator. You know the LC resonator will get "charged up" from your signal source until it meets the voltage of the signal source, so if you add a "power drain" resistor across it, is that conducive to good energy transfer? Sort of like can you take lemons and turn them into lemonade.

MileHigh

Farmhand · « **Reply #116 on:** May 17, 2013, 11:20:28 PM »

Yes well that may be true for a resonator with no load and the impedance is not infinite except the load voltage and phase matches the supply. What then happens when the secondary is loaded and energy is removed from the system ?

The very technical words and the skirting the issues does not concern me.

If the circuit was tuned to resonance before the supply was connected then in the first instant the primary is energized the supply faces no such impedance. True?

And generally speaking a Tesla transformer has the primary coil tuned to a slightly lower frequency than the secondary because the secondary resonance frequency drops when loaded. Then the secondary resonance frequency better matches the primary and energy is cast out of the system quite quickly. But it keeps on drawing power from the supply or it would not work.

This coil below won't work like that unless the primary is tuned to resonance frequency just a tad lower than the secondary resonance frequency (unloaded). Input is about 250 to 480 Watts

http://www.youtube.com/watch?v=1nkJtrKCdFg

Cheers

P.S. Technically you are probably correct but, to the layman or the intuitive experimenter it doesn't matter that much as long as we understand what is going on. We do that by doing and observing. If the impedance is maximum then that is a lot different to infinite.

My Tesla coil primary is only shunted by the primary capacitors when the spark gap fires, when the gap is not conducting the primary has no capacitors.

..

MileHigh · « **Reply #117 on:** May 17, 2013, 11:48:32 PM »

Magluvin:

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You are talking about a normal coil. You ignore what Tesla, TK(above) and I have been saying about the bifi coil. You just revert back to there is only inductance in the coil. You deny that anything is different in the bifi coil, yet never built one nor tested one as I read it.

Well if you can restate what's different and show some test results from past or current experiments that would be great. I discussed these coils as stand alone entities without dealing with a pulse motor setup where we know that either type of coil will export energy to the rotor. As stand-alone entities there is no "magic fast energizing" for a series bifilar coil that has the same inductance as a regular coil. I can't see them being different as a drive coil.

It's possible that you and Farmhand are leading yourselves down the wrong garden path. It can happen to anybody. So it's a good exercise to give these concepts a critical analysis. Throwing a slogan at a technical point with no sound technical basis behind it is unwise. Right now there is no sound technical basis to state that a series bifilar coil will energize faster and give you better performance for reasons already explained.

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You are not making any sense.

No, I am making perfect sense. The only ways to get current to flow through a coil faster is to increase the excitation voltage and/or decrease the inductance of the coil. It has nothing to do with 1.5 volt pulse motors.

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If the bifi were made to oscillate at say 1khz, the pulsing that coil with a 1ms pulse would be accepted into the coil very well as it is in the freq range.

Hard to say because there is not enough information. If you are talking self-resonance here, that's one big mother of a coil.

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Again, and I went over this in my post, you are ignoring facts about the bifi operation because you just cant get past the idea that the bifi is any different than a normal coil. There really isnt much sense in me trying to describe it to you any further as its clear you are in denial and full rejection of what is being stated in the patent, or you are just not understanding it. I, or anyone can only go so far to break down your wall of disbelief.

The patent and your bench pulse motors have nothing to do with each other and it's a mistake to suggest that they do. If you have "facts" about bifilar operation and can clearly demonstrate them then please do so.

MileHigh

Farmhand · « **Reply #118 on:** May 18, 2013, 12:06:18 AM »

Mags, this picaxe controlled boost converter looks fairly efficient. It can pass 50 to 60 Watts of power from 12 into 24 volts potential.

http://www.youtube.com/watch?v=eLnNgfaha10

I can provide the schematic and the code if anyone wants it, but the code has to be optimised for the coils.

Cheers

MileHigh · « **Reply #119 on:** May 18, 2013, 12:28:35 AM »

Farmhand:

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P.S. Technically you are probably correct but, to the layman or the intuitive experimenter it doesn't matter that much as long as we understand what is going on. We do that by doing and observing. If the impedance is maximum then that is a lot different to infinite.

I have already stated that in electronics things are not always what they seem at first glance. And I have stated that it's not easy to visualize the operation of a circuit or a pulse motor. The bench is your reference, keeping in mind the "first glance" caveat. And you can't forget that the more bench skills and experience and background knowledge you have, the better off you are on the bench. But there are things that you can visualize too.

If there are Sacred Cows where it's interesting to kick the tires and have a second look, so much the better. Using the "power comes up from the ground" as an example, avoiding months of experimenting with false conceptions in your mind would be a really good thing! You yourself have already seen things like this before, as I suppose all of us have. Just a few weeks ago we had, "the series bifilar coil makes a more powerful electromagnet" topic come up - it wasn't true.

How about this basic idea for the most efficient pulse drive coil setup and timing: Lets assume a standard pulse motor configuration. Let's say top-dead-center is zero degrees. As the rotor magnet moves past TDC the angle increases. Let's say the magnet feels the most torque from the drive coil at 8 degrees past TDC.

So if 8 degrees is the "sweet spot angle," why not energize the coil at say 4 degrees, and then cut the power at say 9 degrees. Assume the coil has a snubber diode across it, so that it both discharges through the diode and gives a push on the rotor say between 9 and 12 degrees.

If you do your timing right at a given quiescent RPM and make sure the drive coil is pushing on the rotor both before and after the sweet spot angle for maximum torque, and you are recouping a good chunk of the remaining energy in the coil as part of the main rotor push, doesn't that seem sensible?

For completeness, there is overall geometry of the motor to think about also. And very importantly, how much inductance do you use, how many turns? Do you use a core or not, etc? And even the excitation voltage comes into play, you can't ignore it. There is a relationship between the excitation voltage and the inductance and the spinning rotor. Certainly, you could say that your excitation voltage is fixed. Then the amount of inductance in combination with the export of energy to the spinning rotor can be balanced relative to your excitation voltage.

I am always operating on the assumption that your goal is the maximum RPM for a fixed excitation voltage and a minimum power draw from the power supply or battery.

Cheers.

MileHigh

P.S.: For extra completeness, I am going to split hairs even further because it's important. Assume a fixed excitation voltage, and you have complete control over all of the other parameters. Well, if you go purely for maximum RPM, it's safe to assume that you may have a high current draw and a high power draw. So that isn't necessarily the most efficient motor configuration. You could create the unit "RPM per input watt of power" and that would be very interesting because somewhere in the range of RPM, there is a "sweet RPM" that gives you the highest ratio of RPM per input watt of power. What the actual power consumption is at that "sweet RPM" and what the "sweet RPM" is could be determined by measurements. Just a thought.

Finally, I think that you are more interested in driving a generator and putting a useful real-world load on your pulse motor setups. Needless to say, similar efficiency issues could be considered.

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