This is it !

[7imix]

I don't agree. I think Tesla use something else for switching because Tesla mentioned some serious drawback of spark gap, heat and unreliability.

What else do you think he used, and what do you mean for switching? For producing sharp impulses?

You don't agree that a solid state circuit with dc impulses as sharp as a spark gap will have the same effect? You think that something is happening in the gap that is not replicable with solid state components?

[gmeast]

switching

I don't agree. I think Tesla use something else for switching because Tesla mentioned some serious drawback of spark gap, heat and unreliability.

You can get pretty rapid, short duty-cycle with mechanical contacts and brushes on an rotating armature/commutator.

[gmeast]

circuit

Hi all,

Today I rested from a job building an energy recovery system for a laundromat and built the little PWM.

It worked right off, but I am not impressed with the performance ... sorry.

I'm not sure if its better than this when triggering a gate driver or not. Anyway, the best I can do for a short duty-cycle is 1.14% and I had to lower the frequency to about 900Hz to get that. I was able to adjust it down a little more so wave1 is a newer pic of shorter duty-cycle (second pic is better ... see parameters).

Now if you have a big coil with allot of inductance then you won't saturate the coil at this frequency and this duty cycle.

I have included some pictures here.

http://02d1852.netsolhost.com/radiant/wave0.jpg
http://02d1852.netsolhost.com/radiant/wave1.jpg
http://02d1852.netsolhost.com/radiant/circuit0.jpg

There are some tricks to sharpen it up some ... this is just the straight-up circuit that I posted earlier.

Greg

[sucahyo]

What else do you think he used, and what do you mean for switching? For producing sharp impulses?

Liquid mercury. Two people mention to never observe spark when using mercury switch.

You don't agree that a solid state circuit with dc impulses as sharp as a spark gap will have the same effect? You think that something is happening in the gap that is not replicable with solid state components?

Only the purity is different. I think solid state can be better than usual spark gap, but never to what Tesla use. More bellow.

You can get pretty rapid, short duty-cycle with mechanical contacts and brushes on an rotating armature/commutator.

The problem with mechanical contact is spark at the contact point. So we have two spark, spark at the spark gap and spark at the contact point.

The spark at the contact point is a huge waste, reduce efficiency, reduce reliability, create heat, etc. We can only reach Tesla level of switching if we can somehow create a sparkless mechanical switching.

I think this what can make a 1 amp solid state perform much better than 1 amp sparking mechanical switching.

[crackahcrackah]

What else do you think he used, and what do you mean for switching? For producing sharp impulses?

You don't agree that a solid state circuit with dc impulses as sharp as a spark gap will have the same effect? You think that something is happening in the gap that is not replicable with solid state components?

Tesla DID use the spark gap, in conjunction with capacitors to achieve the best effects. He states no less in the 3 lectures on high freq. currents. And I think solid state just isn't the way to go for simplicities sake. Literally repeating one of his high freq. patents, which are based on capacitive discharge is the most straight forward way to go.

The spark gap quite simply permits voltage levels that FETs and other solid state switches, that I am aware of, can not handle.

If you want to reproduce the lighting effects that Tesla produced, then you want a minimum of 20KV at 15KHz for the pulses. I've seen FETs that do like 3KV or so but nothing higher.

[crackahcrackah]

You can get pretty rapid, short duty-cycle with mechanical contacts and brushes on an rotating armature/commutator.

Tesla did that in the patent I replicated via solid state. The 568,176 if I remember correctly. The Imhotep circuit some what mimics this but it doesn't function to it's full potential imho. The concept was great, using a relay, but the circuit was not designed to mimic the Tesla high frequency patents. It does increase efficiency, but there's that whole isolating the longitudinal waves from the transverse waves which Tesla did with his work.

Just pick what ever seems the easiest to implement for right now, to get proof of principle. The relay can be used in place of the motor that tesla used, just be sure to lay the rest of the circuit out following his consistent geometric configurations. I never got around to trying this with the relay but it's on my list of things I want to do when I'm a little less crippled.

Ideally, solid state devices can be avoided, at least initially. I foresee replications of Tesla's high freq. work more in line with what he was working with, and I believe that the components required will be easier to obtain thus opening up a huge explosion of use.

[crackahcrackah]

We can only reach Tesla level of switching if we can somehow create a sparkless mechanical switching.

Magnetic quenching . And I think custom spark gaps which are in a vaccuum based one what he said.

[crackahcrackah]

When the standing or stationary wave (tesla made a distinction between these two terms, it's not clear to me what it is) is in the coil, perhaps the backspikes are bigger.

Standing wave being harmonics, ie: 10Khz, 20Khz, 40Khz , and stationary wave being your longitudinal wave (scalar potential). I actually used wikipedia to study the patterns for transverse waves, longitudinal waves, standing waves,etc. It helps to visualize things and then it's easier to imagine in your mind when you're thinking about this stuff.

The longitudinal wave appears stationary. In Tesla's writings he describes it as "nodes". There's peaks and troughs, but they stay in place, hence the whole stationary bit.

It might be worth cutting and pasting posts like this one, or others that go into more detail, into a reference note file. It just makes studying and referencing come faster to you like formula's for trigonometry or some such.

[7imix]

Standing wave being harmonics, ie: 10Khz, 20Khz, 40Khz , and stationary wave being your longitudinal wave (scalar potential). I actually used wikipedia to study the patterns for transverse waves, longitudinal waves, standing waves,etc. It helps to visualize things and then it's easier to imagine in your mind when you're thinking about this stuff.

The longitudinal wave appears stationary. In Tesla's writings he describes it as "nodes". There's peaks and troughs, but they stay in place, hence the whole stationary bit.

It might be worth cutting and pasting posts like this one, or others that go into more detail, into a reference note file. It just makes studying and referencing come faster to you like formula's for trigonometry or some such.

Thank you, that helps a lot. That fits with my own intuitive visualization as well.

[gmeast]

sparks

Tesla's HF work involved caps, coils and gaps. The spark gap frequencies we high and fairly self-determinate. No doubt this gives the fastest, sharpest rise ... like what we're looking for. But this reminds me of the 'Mosfet Heater" research going on. A Mosfet is coaxed into 'runaway oscillation' driving an inductive heater, (can look like a wire-wound power resistor). The trace is very high frequency with very, very sharp & rapid rise-fall spikes.

So what about capacitive discharge, but that requires HV & HV Caps, otherwise any cap would be too slow with Low Voltage ... maybe. My work on the Water Spark Plug showed me that an HV cap at only 300-400VDC discharges fast enough across an air gap to meet our 'need for speed' but how fast would it discharge into a coil? An SCR is very well suited for such a configuration. SCRs have got to be the most rugged component I can think of to do this ... and they can handle the current. I think Tesla would have liked SCRs.

But I really like the idea of staying at low voltage.

What happens when you discharge a cap into a coil? Does it dampen out, slow-charge the coil as the cap peters out? Is there a recoil or collapse at the end of the coil 'charge cycle? ... keeping in mind we do NOT want to approach saturation.

Oh well, there ya go. More fog,

Greg

[sucahyo]

The spark gap quite simply permits voltage levels that FETs and other solid state switches, that I am aware of, can not handle.

Voltage level maybe higher, but not the current level.

The Imhotep circuit some what mimics this but it doesn't function to it's full potential imho. The concept was great, using a relay, but the circuit was not designed to mimic the Tesla high frequency patents.

I once compare imhotep self oscillating relay run full speed at about 8 Hz, with stingo. For 5 hour I don't notice charge going into the battery. I can increase the power by adding low impedance coil, but as current flow increase, the contact spark become a problem.
YouTube - Unwanted spike in a relay

Magnetic quenching . And I think custom spark gaps which are in a vaccuum based one what he said.

I think vacuum will not suppressing it, at least it will reduce the heat.

Inquorate found that magnetic quenching may be good to force the spark to flow to one direction but may require very very big neo. And Ben already use big enough neo. A problem with neo is neo also a conductor, too close can disturb the spark flow.

The important thing is, magnetic quenching may not solve contact spark problem.

Tesla use mercury at later oscillator. There is patent for it.


BTW, becarefull with spark that flow on one direction. Don't do your experiment near any electronic. Do it more than 5 meter away. as comparison, spark at primary (low voltage) can disturb keyboard at 3 meter away.

[7imix]

Tesla use mercury at later oscillator. There is patent for it.

I'm very interested in that, do you know the patent number?

[sucahyo]

I'm very interested in that, do you know the patent number?

Sorry, I forgot it. But this may help:
Turn Of The Century Electrotherapy Museum Patent Collection

@Jetijs

I'm not saying that it's impossible for some turbines to get over 100'000 RPM but they're extremely small turbines not being capable of sustaining any mechanical weights like the electrodes of the sparkgap. Also, even with the forced airflow quenching the amount of ionization in such a small volume would be insurmountable problem. Even with hard vacuum one would face the problem of insulation, premature sparking etc.


@Electrotek

You're quite correct. The technological challenge poses a simple choice- either one choose to achieve higher RPM and have to use smaller plates or one choose to use bigger plates with more electrodes but then goes to smaller RPM.

I used a small very precisely made rotational sparkgap with 10 electrodes. I was able to achieve up to 10'000 RPM before vibrations become significant. Even with that sparkgap I was able to achieve mere 600-700 us period between pulses. Of course the pulse itself was not in the lower us range since the arc stretching was prolonging the duration of spark.

Also, increasing vibrations means increasingly non-precise triggering since the sparkgap will vary.


One solution to those kind of problems would be to use rotary mercury interrupter but those tend to be very expensive, thery are not easily homemade even with appropriate skills and tools and they rarely go above several thousand RPM. At the time I had some need for rotary interrupters so I consulted the engineers at the university who made some of those interrupters and I quickly abandoned the idea of using one because it could not get me to high frequencies needed and they were also operating to about several kV not more. They are great for large Tesla coils though because they can handle quite a lot of current which would ordinarily burn ordinary solid electrodes- even the tungsten alloys like thoriated ones and such.

[crackahcrackah]

Thank you, that helps a lot. That fits with my own intuitive visualization as well.

One other thing that has helped me, in conjunction with studying the patterns and names online, is just studying water. The aether is supposed to be in motion and incompressable, so it's more like a gas than any thing else, but gases aren't readily observable and water shares a lot of the fluidity properties.

Just soaking in the bath tub gives one plenty of compression and transverse waves to observe. And then there's standing waves if you time moving your arms in synchronization with observable patterns. The compression (displacement?) waves are observable as you insert or remove body parts from the tub. And then there's all of the interference patterns that occur from combinations of movements which are not in resonance.

Honestly, it's a great tool for all of us who are learning and studying the nature of energy. It's also perfect for training our children while they're young.

[crackahcrackah]

So what about capacitive discharge, but that requires HV & HV Caps, otherwise any cap would be too slow with Low Voltage ... maybe. My work on the Water Spark Plug showed me that an HV cap at only 300-400VDC discharges fast enough across an air gap to meet our 'need for speed' but how fast would it discharge into a coil? An SCR is very well suited for such a configuration. SCRs have got to be the most rugged component I can think of to do this ... and they can handle the current. I think Tesla would have liked SCRs.

I don't know much about SCRs. I've heard of them and only spent a short period studying datasheets to know that they don't handle the voltage that we should be pushing for based on Tesla's writings.

But I really like the idea of staying at low voltage.

You can stay at lower voltage but it should be understood that it is the pure voltage, longitudinal waves, that are used for the execution of novel forms of work. 20KV at 15Khz is what Tesla says is the bare minimum for good effects in creating light.

Home made caps can suffice. They aren't too expensive when made either. There are a few patents that tesla has on how to make the type of caps he used for this work. They are all either oil filled caps, or the best that he devised used a saline solution for the armatures of the caps. I started making these latter ones but haven't been able to complete (ahh..the joys of being cripple).