Why do we use multi-filar coils?

[serendipitor]

I am wondering why the focus on multi-filar wound coils, and the seperate transistors for each wire?

Is the idea similar to Paul Babcock's experiment with radiant energy driving a plasma discharge? He gives a first guess at a number of watts per unit length of wire, based on his 8500' coil.

I thought of a test, which is to make two coils of as nearly equal form, inductance, and resistance as possible. One would use a single larger gauge wire and the other an equivalent size litz wire winding. Discharge these two into a large capacitor bank for a finite number of pulses, and see if there is any difference in the rise time of the capacitors. The question to be answered is: Which is the important factor in gethering radiant energy, the length of the magnetic path (as in Babcok's long thin coil wire), or the total length of the wires (as in Bedini's stranded coils, even though the strands are paralleled)?

As for the use of seperate transistors and diodes for each strand, it can't be because of the power levels. My drive input power is less than 10W, and that is certainly well inside the range of one device. If the turn off time is enhanced using multiple paths, that would reason enough, but I can't see why a single device would not be equivalent, given that there are plenty of fast diode and transistors in the world. I am going to look at the wave form and compare as I take and parallel the windings down to just one of the transistors.

I am using FETs and a PWM driver, so there is a slight difference in the circuit from the SG, but otherwise it has comparable function.

If anyone has done these tests, I would like to hear.

Thanks.

[wrtner]

It depends what project you are talking about.

If it is the Bedini SG (or SSG), then it just won't work without a bifilar coil. As the magnet passes the coil, various things happen to the two different windings at the same time. This video is good but it does not mention that the wheel is propelled around by a push from an energised coil:

https://www.youtube.com/watch?v=yi7cmUpMdX8

In the SG, one winding triggers the transistor and the second provides spikes to the collecting battery. I am pretty sure that a third, fourth or fifth windings simply provide more to the battery.

Paul-R

[serendipitor]

My question was oriented towards the so called mono pole generator, which uses 7 strands in the main coil, each with its own transistor and diode. The power in each strand is small, so it does not make sense from a conventional power dissipation point of view.

I did a test just now, and took all the strands in my coil and paralleled them through just one IRF640 (with PWM driver- not using the trigger winding method), and used a fast recovery type diode instead of 1N4007. I found the turn off time to be reduced compared to using seperate transistors and diodes for each strand. This is due to less capacitance from paralleled switches. The difference was not enough to change the conventional current in or out from the circuit however.

I'm just wondering why John B. went the route he did.

[wrtner]

My question was oriented towards the so called mono pole generator, which uses 7 strands in the main coil, each with its own transistor and diode. The power in each strand is small, so it does not make sense from a conventional power dissipation point of view.

The power may be relatively small but there should be a high voltage. Note that John usually specifies 1000v diodes.

I am not certain about this, but I reckon that this design is basically seven SG devices, using one trigger coil to fire the lot of them. Because there are seven separate circuits, you need seven separate insulated copper wires for the coils, seven transistors and so on.

N.B. The seven wires will need to be insulated from each other.