BEMF pulser

[bob.rennips]

EDIT: Sorry folks - this information as presented is wrong. Ignore this information. Earl has pointed out there are problems in the way I've drawn my schematic - which I totally agree. I had moved on to trying to get the circuit to work with caps, as I noted at the end of my original text. My notes concur with what I've put in the schematic, so I'm going to have to go back and do the experiments again, to see where the mismatch is between what I was really doing and what I thought I was doing.

[Earl]

Hi Bob,

see that you had a very fruitful weekend.

CONGRATULATIONS !

We are slowly getting the pieces of the puzzle into place.

I permit myself to make several comments.

The 1000 Volt diodes can not be Schottky types, but they should be as fast as possible.
Slow rectifier diodes like 1N4007 are to be avoided.  At 1000 V lots of fast diodes can be found, whether from silicon or silicon-carbide.  By fast, I mean what is called reverse recovery time diodes.
One can start searching here:
http://www.datasheetcatalog.com/catalog/p10640.shtml

Thanks for finding the JAVA circuit simulation applet from http://www.falstad.com/circuit/
this applet can also be download and run locally on your computer.  I have attached it to this post.  I suggest downloading the latest java version from Sun at:
www.java.com

Of course, your browser should have java scripts enabled.

Bob, can you tell us which diodes, if any, can be lower voltage Schottky types?
I am assuming that ALL diodes must be fast recovery time diodes.

Fantastic research, Bob, keep it up.

Respectfully yours, Earl

[Earl]

Hi All,

to be perfectly precise, there is JAVA and java scripts.  Most browsers permit you to separately enable or disable these two.  You will need to enable java in your browser options to use this circuit simulator.

When you are not using the circuit simulator, it is a good idea to turn off java in your browswer unless you need it for a certain site.  The reason is that java and java scripts can be security hazards, say the experts.

Earl

[bob.rennips]

Hi Earl,

You are quite right to highlight this. They MUST be fast recovery diodes. Thanks for highlighting this omission.

I used MUR8100E (had been using MUR880E) because they work to 1000V, have ultrafast recovery times, hi amps, and low forward voltage and low leakage current. In fact these seems to accept a lot more over voltage abuse - but obviously each time I do this it must reduce the life of the diode.

All the diodes were MUR8100E - I chewed out lots of MUR880E's. Not sure you can replace any with lower voltage schottkys.

http://www.ortodoxism.ro/datasheets/fairchild/MUR8100E.pdf

The Trr (recovery time) is max 100ns or typical 75ns if you can keep the amps down. You can do better on the recovery time but these were cheap at US$ 50c each.

Just to stress the above diagram although drawn using the simulator for ease of drawing is the result of many real world experiments/circuits using this concept.

Also although I've shown both bifilar pulsing of a neo and Tpu Coils together, I'm not suggesting this combination is needed for the TPU. I'm just showing how you would use the circuit in each of these situations... know what I'm saying.

Cheers, Bob

[tao]

BEMF pulser ? this is real world ? tested in various configurations

I?ve combined different circuits together to show how the BEMF can be utilised. A BEMF has high voltage, sharp rise and fall, and is clean ? enough said.

The BEMF generator coil has large number of turns and uses thick wire. The BEMF from this coil is large. Diodes B keep the BEMF (and hold the electric field as per previous experiments I?ve documented) in the BEMF coil, if you don?t add a TAP DIODE T1.

So let?s say you want to pulse a TPU coil with a BEMF pulse. You add a Tap Diode T1 and Diode A to TPU COIL 1 as indicated. You turn the current ON with MOSFET M1 using your pulsing circuitry. This allows current to flow into the BEMF generator coil. Note that V1 will be at a slightly higher potential than V2 so no current flows in TPU COIL 1. When MOSFET M1 is turned OFF abruptly, the BEMF flows via TAP DIODE T1 and diode A through TPU COIL 1. As far as TPU Coil 1 is concerned all it sees is a high voltage pulse with very sharp leading and trailing edges.

......

Congratulations,

This is a very good advancement Bob, And might very well help concerning my impending writeup on the TPU...

Can you believe we are still at this TPU thing Bob? LOL. I remember like a year ago when we were everyday trying to figure this thing out Hopefully the end is near