Your knowledge on this schematic please

[manie]

The circuit is supposed to:

1. Induce some waveform through the Toroidal windings from the Mosfet pulsed 12V onto the 150V dc passing through the load. The Toroid "primary" (left side on schematic) is 43 turns 20AWG wire. The "secondary" (with 150V on it) is 133 turns of 16AWG wire, so roughly 1:3 ratio.
The 2.1uH "heavy duty" chokes are asked for in the original circuit, I suppose to handle spikes etc. ?

My question:
Within the elipse there are 2x resistors as voltage divider and 1x Capacitor across the clamping diode (mosfet protection diode).

1. Will the cap have ANY benefit when placed there ? If it will, what sort of value will be required ?
2. The voltage divider will bias the Mosfet gate to +- 1.95V from the 15V supply. The idea is to keep the Mosfet just below the Gate Threshold voltage which normally starts at +- 2V minimum. Does have any value/benefit ? Quicker Gate charge time maybe ? The TC4420 has built-in totem pole so switch-off should still be quick.
3. Does ANY of this part of the circuit have ANY value ? If it has, kindly explain in short why.

Many thanks for your time
Manie

 

[BeanieBots]

I find the entire circuit a little confusing?
What is it meant to do?

I looks like a very old method of high power AC control.
The idea being that a net DC is passed through one winding of a transformer to reduce its reluctance and hence pass more current. That would explain the cap across the diode but it can't be one of those circuits if those 150v connections are DC.

The inductor in series with the transformer doesn't make sense. If the idea is to superimpose an AC signal in the load over the 300v DC (ish) already across it, then that inductor would simply reduce the effect.

As for the DC bias on the FET's gate. Probably to keep it biased slightly on for improved speed response.

Overall, I am genuinely at a loss with that one. Sorry!

EDIT:

What is the switching speed. That would at least help to understand any component values.

 

[manie]

BB: Thanks for the response. Error on the schematic, the -150V should be 0V, so 150V dc through load and transformer (series coupled).

The Cap across diode is from searching the web, somewhere I saw this, will search again and place link for it. Also the 1.95V +ve bias on the gate came from a web page, and is not part of the original circuit.

The 14A choke in series with the Toroid secondary is exactly as per original circuit. It baffled me also.

Pulsing the primary with 12V dc will happen at the three frequencies I asked about in an earlier thread, 42/28/14 KHz respectively, each into its own "primary" winding, each of 43 turns.... What will the induced pulses achieve, if anything ?

The circuit will power ("energise") another one of my sponsor's ideas with regard to Hydroxy Gas production. The "load" will be cells in series (100 of them), therefore dc required at 150V for 1.5V across each individual cell. The 42/28/14 KHZ pulses all happen at once and is supposed to "enhance gas production" due to the modification of the 150V dc... I have not seen this on the scope yet, so I can't say if anything happens or not. The 100 cell unit is being made right now and the Toroid (all 165mm O/D x 80mm I/D x 50mm H of it) has been wound by a local Toroid manufacturer, beautifull job he did too ! I will place some pics once I have it together. Hence the question on the mosfet modifications as I have had LOTS of overheating problems in the past at moderate amperages (+- 20amps, through 75A x 60V IRF's). Heatsinking does not help much, the mosfets eventually (sooner) leaks ot smoke !
Manie

 

[kevrus]

Maybe the 'custom toroid' is a transductor, sometimes known as a magnetic amplifier.

It has two windings...an AC winding that is in series with the load and a DC winding that is connected to either a varying DC voltage, all wound on a saturable core.
Varying the DC causes a change in saturable magnetic flux hence the reactance of the AC winding and thus the current on the AC side. Commonly found in older style welding sets and sometimes in CCRs (constant current regulators) used on airfield ground lighting (ive worked on both...in fact I still work on the CCRs

One advantage is that the output is more steady and 'sinusoidal' with less 'spikes' than say an ordinary transformer controlled by thyristors, one downside is the speed of reaction to a change in DC control
Pretty much as BB said really

 

[BeanieBots]

Oh... Brown's Gas again!
As this is a pursuit of "something for nothing", I guess the original designer has put in every component for a very specific calculated design reason.

Battery charging has certainly shown that there are distinct advantages to pulsing, 'burping' and Pb technology (apparently) has a resonant frequency in the order of 3Mhz. I guess the generation of Brown's Gas probably has similar quirks, hence the series inductor with the already highly inductive transformer. Although, without data from the manufacturer of the toroid indicating it's leakagae inductance it would be hard to know what value it should be.

So, what value should the cap across the diode be?
Absolutely no idea. Only the original circuit designer (in consultation with the toroid manufacturer) could answer that.
Maybe it was part of a snubber that has lost its 'R'.
In which case, the above problem still applies but an educated guess could be made depending on FET characteristics and 'R' value.

 

[manie]

Thanks BB and Kev.
Kev: There is no AC current there, only DC at 150V and pulsed 12V... the Toroid will act as a step-up transformer it seems. Question is by how much will the pulses modify the 150V dc ?
BB: It seems that it is then feasible to reduce switch-on time by placing a small bias voltage on the Mosfet Gate ? Is the voltage divider OK by itself or is a cap somewhere in there required ?
Manie

 

[jglenn]

The divider I don't think is doing anything. The fet driver will try to put 15V thru
the rather large 220 ohm gate resistor, which will overwhelm the divider when either high or low. When is the gate supposed to be 1.95V? When the fet driver is not powered, is the only case I see.

The cap and diode on the primary is to clamp it, the cap is a snubber. This is a pulse transformer application.

If the fet driver blew up, the divider might keep the fet off, however.
You have to watch open gates, very very tiny signals can turn them on.

 

[manie]

Thanks John, basically what I thought also. Having seen it on other sites I thought it prudent to ask about it. Yes, the divider will keep the Gate just below the threshold voltage when the driver is in the low state, but that is what is supposed to speed up switch-on time. I will try it on strip-board and see...

 

[jglenn]

Manie: I don't think the gate will ever be at 1.95V. The fet driver has low impedance drive for both high and low, ground or 15V, the 220 gate resistor
will slam the divider. I do not believe the bias claim. This fet is being used
as a digital switcher, not analog. All you really need is a pulldown resistor, 100K is fine, in case the driver is not there. That keeps the fet off, and is invisible to the driver.

The 220 ohm I probably would make smaller, like 5 ohm. We used to put ferrite
beads on the lead to tune the gate turn on waveform. Like I say, snubbers also can clean up your waveforms, on the drain too. Usually RC, but there are
variations with diodes, in little networks that do different things.

 

[sleazyd]

The cap is a snubber, and probably there to slow the dv/dt across the FET for some reason. A resistor/diode would absorb some of the reverse spike, but the cap will slow it down some. I'd shoot for a 1uF or so, but it really depends on the switching freq.

 

[gengis]

Oh... Brown's Gas again!
As this is a pursuit of "something for nothing", I guess the original designer has put in every component for a very specific calculated design reason.

Battery charging has certainly shown that there are distinct advantages to pulsing, 'burping' and Pb technology (apparently) has a resonant frequency in the order of 3Mhz. I guess the generation of Brown's Gas probably has similar quirks, hence the series inductor with the already highly inductive transformer. Although, without data from the manufacturer of the toroid indicating it's leakagae inductance it would be hard to know what value it should be.

This has taken on all the earmarks of a religion - you have to have faith, rational logic won't work.

Seems to me the circuit is intended to take a mosfet driver get it to self-oscillate then use that to produce high voltage pulses on the 150 V supply in order to knock gas bubbles off the plates to increase current and gas production. OR he's only giving us part of the circuit.

The area circled is what I would question also - whats the point of getting a 6 amp mosfet driver if you're going to hobble it with a series resistor and bias network on the mosfet? The ops analysis of the circuit is right; this makes no sense at all.

Interesting about the battery charger reference BeanieBots . . . those folks also seem to gravitate to the inductive kick circuit to produce the HV pulses - there, it seems to be a case of the blind leading the blind, maybe this circuit is the same thing.

A while back the US government went and looked at hydrogen fuel, storage and safety . . . and out of a 90+ page document they made some statement to the effect that small amounts of hydrogen injected into diesel engines resulted in more complete combustion in the old test engine they used (along with the caveat that their test method was not scientific). And a religion was born . . .

Seems this was already debunked in several venues, but religions rely on faith, not reproducible results.

Maybe it really does work and all the debunkers went in with the bias that it couldn't work?

 

[manie]

Flooby:

Maybe it really does work and all the debunkers went in with the bias that it couldn't work

The sponsor and I so far are achieving some fuel savings which is encouraging enough to him, to get me to do this circuit etc. Results vary a little and external influences such as driver habits/actual driver(person)/truck payload/elevation etc. seems to all play some roll in the actual saving. What we have debunked is that it DOES NOT make the vehicle more thirsty than it originally was, unlike the religious belief of some doomsday sayers... In the end, it is a form of fuel. If it assists combustion then egine efficiency must improve. By how muchis the problem.....

Edit: That is the whole circuit (except the 08M pulse source...)

 

[gengis]

Ok manie

I think it is very unlikely that "over unity" will ever be achieved short of a Farnsworth or multinational fuser of some sort, and that wouldn't be over unity (to a brown gas enthusiast). Not to say it isn't a worthwhile goal - just the odds are against you. (but if it was easy it would have been done already - devil's advocate)

I also doubt that injection of hydrogen and air could change the dynamics of an ICE to increase fuel efficiency to measurable levels - let alone bragging rights.

The Brown's Gas folks may actually have something there - I can't say. I do know no one in 7+ years has been able to reproduce the "effect."

I do know I built "hydrogen bombs" as a kid and any collection of air, or worse, oxygen, and hydrogen in the same container is asking for trouble. I made hydrogen from aluminum foil and lye - and draw that out discharge to a capillary and it melts glass - and make one little mistake, and it is very impressive - that's just hydrogen - we kids electrolyzed water to make our bombs and they were most impressive. 4 cubic inches, from forty feet away.

Thing is - whenever "Magnets" and "Resonance" get together - especially where one wants to work in the resonant frequency of a planet, cosmos, or just a lead acid battery, there's fraud afoot.

Nothing is achieved without dreams. But stay skeptical.

And for god's sake post your results - I'm an agnostic not an atheist.

 

[Dippy]

With all this mysticism I have lost the thread of this thead...

Is it: "I have this magic circuit, will it work?"
Or is it "I have pinched this circuit to generate 150V, but it doesn't seem to work correctly."

Personally, I think it looks horrible, but if it works then who am I to say...?

 

[lanternfish]

With all this mysticism I have lost the thread of this thead...

Is it: "I have this magic circuit, will it work?"
Or is it "I have pinched this circuit to generate 150V, but it doesn't seem to work correctly."

Personally, I think it looks horrible, but if it works then who am I to say...?

We are way off topic, but then so are those that believe the injection of incredibly small amounts of hydrogen into an ICE will increase efficiency. Any good chemistry book will give excellent 'proven' characteristics of hydrogen.

As for the circuit in question - who has a suitable simulator. A lot of unknowns re the output transformer, but other than that ....

 

[lanternfish]

Looking at the app notes for the TC4420 http://ww1.microchip.com/downloads/en/AppNotes/00798a.pdf maybe the components upto and including the MOSFET are a delay line driver and voltage translator (Fig. 33); the capacitor and resistor take the place of the delay line. A bit of a stretch.

Seems unusual to have an RC parallel circuit (usually seen in AC circuits) in a DC circuit. Can only think that the 15V supply is meant to be AC!?

 

[gengis]

Seems unusual to have an RC parallel circuit (usually seen in AC circuits) in a DC circuit. Can only think that the 15V supply is meant to be AC!?

Not if the plan is to impose a sudden high voltage spike of opposite polarity on the DC used in electrolysis, but that begs the question why use DC when a 150 V AC square wave might work better.

The inductor is there to appear as a high impedance to the spike, so it doesn't dissipate in the 150 V power source.

They allow the oxygen and hydrogen to collect and mix in the same vessel so there's no need for DC.

 

[manie]

Floby: AC will give you zero production, you must polarize to interact with the +ve and -ve ions. I've opted for the straight standard mosfet drive, from TC4420 to Gate with a 1k between gate and 0V and a transorb across the gate for spikes. Also a diode off course across the inductor for reverse feedback...

Dippy: Nothing mystical, this circuit is freely available, I've asked questions around "other" circuits I've seen in the web and because of the dismal LIFE expectancy of any mosfet once I start pushing even a little amperage. Thought there might be benefit in the pieces circled in the schematic, but now I've opted for the standard circuit.

I will post results no matter whether pos or neg... my sponsor in this case believes in "open" research and results, he's a keen tinkerer but knows zero of electronics. So thats how I'm involved and sometimes the results astounded even me, though a stand on the skeptical side of Browns Gas.... At least I get to try things with Picaxe and electronics, so I'm learning something....