Use for the Tesla Switch

[chainmailleman]

Are you wanting to make a Solid State
version of the switch?

No, for the reasons because I can't make a transistor from scratch and when working with kilowatts, solid state valves are very limited and very expensive.

Unless I work with large triodes, I am stuck with mechanical switching. Commutators are faster than relays and have less "chatter".

[Matthew Jones]

OK Matt!
My diagram didn't attempt to show 'rectification;'
only a simple bank-switching scheme to implement
the Brandt alternating output. Actually, it could
even be reduced to simpler switching than I've
shown.
Would you rather have a pulsating DC output instead
of the alternating output?
Looking forward to your diagram...

@SeaMonkey, I don't think it matter what the output is That would be dependent on the load you need. I am growing more curious by the day about driving the transformer as I have started to see some neat results from a test model I have running. So we can go with that for a basic model.

I think this how I did it.
Mosfet Tesla Switch.
I didn't write in all the controls for the Opto's cause I didn't want to clutter the thing up. But all pretty obvious as its the simplest thing I could come up with. Its takes advantage of the lock on the mosfets, SeaMonkey mentioned that.
Based on which side you want to control at a given time the Green Opto's turn it on. the red turn it off.
The green opto's were "h11d1" and the reds were "h11d2a". I can t figure it out but the h11d2a's drive a ground current well but have to be wired backwards.

I used 2, 12 volt 1 amp halogens. Each one running a different direction. This schematic could be used to drive the transformer as RB did, or you could rectify the load with 4 more switch's as I outlined in post #3091.

You don't need any resistance on the gates, nor do you need resistance when using a BJT. In both cases they just lead to heat and low potential produced in the transistor. This is something I tested just recently. Fill free to test it for yourself. I don't know if this is correct I just noticed more heat when using resistance on the base or gate, so Ileft it out.

The biggest problem I had and the only reason I didn't persue it was when I started using an inductive load the serial switch's burnt up. I added a fast diode from the ground back to the hot (Picture the arrow for diode pointing toward the hot side of the serial connection). And that work fine but then Positive side switch's burnt and when I added protection at that point I had to slow switch's down to get the load to respond and lots of heat showed up the in the Positive side switch's.

It was all done in a bread board.

I spent a little time looking into better ways to drive them but its all above my head at the moment. So she just got set off to the side as I went back to mosfet driven SSR's. Which I am looking into building myself. So this circiut may pan out to applicable if driving them gets a little easier or robust or something...
No doubt we'll have to find a better mosfet, that doesn't burn up so easy.

Matt

[nvisser]

Stevan
Could you redraw the Palindrome's circuit into an understandable format and maybe give some specs on the trafo's you are talking about. I cant even see them in the diagram.

[StevanC]

I would not be too dismissive to that design?
Once I'm done with PV switchers I'm coming to Brandt types, and it will be MOSFET or bust

1. And I would use drivers in between the gates and the trafo outputs
2. MOSFETs have gate leakage (a lot in 500msec Que-times - 100uF (!!) caps needed for bootstraping the "Vboost"
3. The CP (charge pump) layout seems to be lacking the "kick" my booster has:
Since it does not insulate the capacitors the instant it commences the "dump" Que, they seem to kick both sides: a part of the kick is "back fired" and thus lost as far as I can tell? Is this really the case or am I missing something?

And i did have a excellent kick (+30A peak) with the 7BJT version (=more losses) but now with the 2 parallel BJT version I have it not?

Circuit symmetry? Can symmetry pay more toll than wire gauge?

Best regards,
Stevan C.

[nvisser]

Sorry I can't spend time and money on a circuit designed by an academic that does not even know how to test a transistor with a multimeter. He also believes that MOSFETs have no gate current as in the electronic tutorials. Wonder why a mosfet driver can deliver up to 6A of instantaneous gate current.
I don't make out anything on that circuit anyway.
I will wait for your design.

[SeaMonkey]

You're much closer than you might think!

Look at lanenal's diagram once again.

It is in THIS THREAD

lanenal = Palindrome

[nvisser]

No. We are not nearly there.
This is where you come in.
We got no idea how to do it.
Throw a diagram our way and some of us might try it.

[SeaMonkey]

Dave has done it and some of us has built it.
That is the one that you said was to complicated.
Also no diodes.
He used modified low side drivers to drive the 2 high sides and he used low side switches for the serial parts. It looks only so complicated because he used a lot of diodes to get the floating supply to drive everything with.

I concur. The driving circuitry was entirely
too complicated.

Anyone know why he didn't utilize transformer drive?

[SeaMonkey]

Hi Seamonkey
I noticed that you are really getting into the Tesla switch threads now.
Can we expect a simplified mosfet version from you soon.
I remember you mentioned earlier that it requires only the two series switches to be fets and that the parallel switches could be mechanical.
I may be mistaken?
As you are new into the TS I will also post John Bedini's original circuit that caused lots of trouble for him in the eighties. He used audio transformer to get the fast switching from bipolar transistors

It is 'possible' to devise a circuit using
virtually any combination of mechanical,
electromechanical and solid state switches.
Some combinations will be more cumbersome
than others, but it can be done.

Bedini's circuit is conceptually very good, even though
it is excessively complicated. It is possible, as you've
already shown with your previously posted diagrams,
to simplify it considerably.

Bedini was correct to attempt to drive the transistors
with transformers as 'floating' switches. It is the
only sensible way to provide base current to the
array of individual transistors.

Unfortunately, it is difficult to use transformer feed
for transistors at low frequencies. They work well
for several KHz and up, but for the 900 Hz or
thereabouts that Brandt found to be the 'resonant'
frequency of the batteries, it would not be effective.

But for MosFets, the transformer drive will work
very well indeed. The MosFet doesn't require a
continuous Gate current in order to keep it turned
'on.' Just a brief 'pulse' of Gate current to 'charge'
the Gate capacitance will keep it in the 'on' state
for a considerable length of time - limited only by
the 'leakage' of the Gate circuit.

Therefore, the MosFet implementation of the
battery switching circuit will be a 'natural' from
the standpoints of ease of construction as well
as efficiency of operation. It will also be possible
to operate the circuit over a broad range of
frequencies while 'dialing in' the resonance.

Shazam!! You guys are nearly there already!

[nvisser]

Dave has done it and some of us has built it.
That is the one that you said was to complicated.
Also no diodes.
He used modified low side drivers to drive the 2 high sides and he used low side switches for the serial parts. It looks only so complicated because he used a lot of diodes to get the floating supply to drive everything with.

[SeaMonkey]

Unfortunately that is double throw switches or relays. It is not so easy with transistors as they can't switch in two directions.
Here is an diagram that uses only 3 relays. It is like Cifta's transistor diagram but with relays. I will post both.

Yes! Very good!

I found another by lanenal in the index as well.

It is gratifying to find that the 'solution' has
essentially been worked out already!

Why has no one made the transition to a
MosFet version except for lanenal?

You'll find it HERE

[nvisser]

Hi Seamonkey
I noticed that you are really getting into the Tesla switch threads now.
Can we expect a simplified mosfet version from you soon.
I remember you mentioned earlier that it requires only the two series switches to be fets and that the parallel switches could be mechanical.
I may be mistaken?
As you are new into the TS I will also post John Bedini's original circuit that caused lots of trouble for him in the eighties. He used audio transformer to get the fast switching from bipolar transistors

[nvisser]

Simplest diode-less configuration.

Unfortunately that is double throw switches or relays. It is not so easy with transistors as they can't switch in two directions.
Here is an diagram that uses only 3 relays. It is like Cifta's transistor diagram but with relays. I will post both.

[SeaMonkey]

Thats the basics of my model.

Are you wanting to make a Solid State
version of the switch?

[chainmailleman]

Simplest diode-less configuration.

Thats the basics of my model.