Eldarion and Bruce's build of Bob's Energy Converter

[HumblePie]

The only thing I have noted as of yet is that I can vary the primary drive frequency all I want, and to some extent the pulse width, and no matter what frequency I use the HV back-EMF pulses on the primary always occur at 10uS intervals--even when there are drive pulses in between the observed back-EMF pulses!  Also, they are a bit odd in shape, perfectly symmetrical about a peak and there is no indication of ringing.  I haven't really seen that in any other inductive system.

Eldarion

@Eldarion,

It sounds kind of like the Solitron Scaler Wave transmitter based on Cadeous / Tensor long, standing coil.  So strange that this pulse is not attached to the stimulus pulse at all.  I bet it has to do with what is posted in Grumpy's Pulsers thread showing the animations of TEM and LMD reactions to stimulus being distinctly different from one another.


I tried to find the link to the Solitron, but found this by accident at Youtube:  http://www.youtube.com/watch?v=NQHTrZbyUE0&feature=related

Wow, Obelisks were scaler wave controllers that draw water up like a pump.  The video shows an installation doing this and oh yes barbed wire and armed guards.  In USA, the public has tolerated individuals being arrested and held without charges for "Photographing critical infrastructure".  If you get caught doing so, they do not even tell your family they are holding you, even when asked and shown missing persons Police reports.       

Beware of what we have become... much like what the Soviets were once despised for.  Waterboarding is drowning, resuscitation, repeat, until death by 'natural causes' (lack of endurance to hypothermia, inhaling water, etc).  I do apologize for talking politics when it has no place here.  I mean only to warn others in USA NOT to photograph... that you have no rights anymore, and maybe never really did...  just an illusion really, restrained by occasionally 'uncomfortable' public visibility .

I will post the Solitron link when I can find it among my failed bookmark imports from WinXP.

Ward

[eldarion]

Hey,

Just thought I'd drop in to say that yes, I am still alive and I am still working on getting this converter working!

Attached is a scope shot of one of the 500ns pulses across the primary coil.  As you can see, things have improved considerably since my last postings in terms of pulse shape and ringing.  I am still attempting to remove the last bit of ringing that is still present; hopefully once that is gone we will start to see some effects.

Just a note to all builders: Bob and Earl are absolutely correct when they say to treat this thing as if it is an RF circuit.  This holds true for all interconnects, not only the MOSFET gate drive!  There are frequencies flowing through the coils that are in excess of 50MHz, and they help to create the nice, clean square waves.  Using high resistance, high inductance interconnects and unsoldered connections will really foul things up.

I have switched back to using IRF510 MOSFETs, purely for the switching speed.  I mounted three of them on a nice big heatsink (with appropriate insulating hardware), and have not yet blown any of them (they don't even get warm with 500ns pulses).

Low-inductance speaker wire seems to work wonders, as well as the liberal use of distributed power supply filter capacitors.  Don't just stick all your power supply filter caps on one piece of perfboard 1.5 meters from the switching devices and expect the signals to be clean (yes, this is the voice of experience talking here--pretty stupid!)  I have a small value filter capacitor sitting right on the coil's positive leads where they all connect, and it reduced the ringing duration by almost half.  DON'T USE A HIGH VALUE ELECTROLYTIC--it will not work at RF, and the voltage will sag horribly!  (Not the voice of experience here, simple math will explain this one)

Well, more coming soon, I hope...

Eldarion

[Earl]

Eldarion,

I don't understand the waveform.  It seems to me that the first part of the waveform is when the drain shorts to ground.  This should look like the straight red corner.  Don't understand the lazy, slopping descent to ground.  Second, there are spikes going negative that I don't understand.  Third, after the ringing settles down, there remains a constant amplitude sine wave, which I don't understand; would expect to see a flat, horizontal line as shown in green.  The first cycle of this sine wave is very noisy.  Fourth, don't see any HV spike(s) going positive to 100, 200, 400, 1000 Volts.  A lot of puzzling things, which indicate to me that something(s) are not quite right in your circuit, measurement, or both.

It would be important to know if this constant amplitude sine wave is an artifact (hum??bad grounding??) or an [interesting] anomaly, e.g. what is the source of this sine wave?  I t appears that the period is roughly 500ns, which means about 2 MHz.  I have seen an anomaly of a constant amplitude sine wave after perturbing a magnetic field, but in my case the frequency was about 100 MHz.

Earl

[MarkSnoswell]

would be important to know if this constant amplitude sine wave is an artifact (hum??bad grounding??) or an [interesting] anomaly, e.g. what is the source of this sine wave?  I t appears that the period is roughly 500ns, which means about 2 MHz. 

Nothing here looks out of the ordinary to me -- all things I have seen in practice. The initla poor pulse shape looks like the result of insufficent bypass caps and/or inductive wiring between the mosfet switch and the load.
The 2MHz ringing is not constant amplitude -- I have seen ringing like that in both simulations and in paractice -- ringing that can presist right into the next pulse. If you look at the envelope over a longer time frame you see that it is decaying as expected.

It takes a *lot* of effort to get clean pulses at the coil. However I dont know that this is a goal that is productive.

Mark. 

[eldarion]

Hello all,

It was my understanding that the pulse shape (incuding that the pulse is unidirectional, i.e. no ringing!) is extremely important to get the effects to show up.  Bob has mentioned several times things like "If you do not see the effects, then your pulses may not be of sharp enough rise/fall times"; "drive each of the 120 degree coils in phase with very sharp and narrow unipolar negative DC pulses"; etc. 

If I am wrong here please correct me, as it is very difficult to get the pulses cleaned up and get rid of the ringing!

It looks like the inductance of my interconnects is still way too high, so I will try some Litz wire and see if that might help.  These are not long connections (max. six inches, simply due to the way the coils are wound), but they are wreaking havoc on the pulses and the pulse generator.  As of right now, the entire assembly wants to go into a very powerful 2MHz resonance, which sucks down about 2A @13.8V, raises the voltage at the other end of the power wires by almost double, and strongly affects my CRT monitor.  Not good!

I am using three 10-ohm power resistors to dampen the ringing, but the inductance of the interconnects has completely drowned out any effect they might be having.  My circuit looks good in simulations, I just have to get all the parasitics reduced as far as possible.

I wonder if short runs of coaxial cable to the coils might be of any help here?  Right now the coil leads themselves are about 6" long, but I am hesitant to cut them off right near the actual coils, as there is no way to undo that operation.

Maybe Bob can offer some guidance here?

Eldarion