A 50kV supply with 33mA drive ability

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Richard Hull
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Re: A 50kV supply with 33mA drive ability

Post by Richard Hull » Wed Jan 13, 2021 5:24 pm

I doubt if a pressure versus voltage will be of any value based on fusor type and size and special circumstances due to this. We have observed this forever, here. Every odd fusor from big to small demands the operator to learn how his pressure voltage and current respond to actually do fusion.

As to kickback in a struck plasma, this never happens in a stable, fully functional power supply that is not some sort of current controller mess of a supply that is being operated on the ragged edge of its capability.
A huge strong supply of 4kw of continuous capacity will never burp once the plasma is lit. It has never happened to me with my heavy x-ray transformer. There is no multiplier and no storage capacitor in the entire system! It is 120hz full bore ripple! I will let others chime in who have had it happen to them and I recommend when they chime it, they give full data about their fusor, shape, size, etc., and what supply they are using.

I am unaware of any living being here doing significant fusion who is using non-multiplied 40-50kv full wave rectified, non-filtered HV at 120hz full ripple. Most with issues are using HF switchers professional or of the precipitator type that are ostensibly pure smoothed DC. while at the same time, they are working close to the ragged edge of its capability. Some seem to have mastered this cliff-hanger supply situation like Mark Rowley, which means he is a plus-ultra operator and has the skill set for his specific device under his full and able control. Mark has had a few smoke plumes in his early work, but not lately. He has learned the "rope limit" while circumnavigating his switcher supply, with a suitable supply of spare components in case he dare challenge the supply and lose that bout in the ring.

The big hassle for many is that monster startup current drain. All gas glow systems have a large start up hysteresis. In the case of my fusor, once conditioned, this can be 15kv work of differential. wants to smoothly run at startup at 15kv but strikes at 26kv. the 63k ohm 125 watt resistor takes it on the chin until I dial the voltage back. Due to my skilled operation, I usually have it functioning at 30kv glow a minute or two after striking. From there I do my spider monkey routine adjusting the pressure smoothly to meet a "feel" for the current as I creep the voltage and fusion ever upward. It is an art. It makes it easy when you need not even let your power supply capability enter your stream of consciousness.

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
Retired now...Doing only what I want and not what I should...every day is a saturday.

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Finn Hammer
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Re: A 50kV supply with 33mA drive ability

Post by Finn Hammer » Tue Jan 19, 2021 4:07 pm

Victor,

You are right, basket coil winding is a lost art, and a complete separate project.

I bought a MoReCo winder on EBay, and it is a piece of junk, really, but if you nurse it a bit, it can be brought to work. There is a lot of unwanted slack in it though.

It looks like this:

IMG_20210119_145318.jpg

The brass handle on the *drive shaft* is the center of action, and turning it creates the two required motions, the rotation of the bobbin and the reciprocating motion of the wire guide.
The drive shaft also has a cam which produces a reciprocating motion on the (shall we call it *cam shaft* ;-) ) which transmits it to the wire guide.
The bobbin is fitted between 2 wooden cones at the far left on the *winding shaft*. the drive shaft and winding shaft are meshed together with a set of gears, where the driving gear is the smallest, and this is important, because to get a proper lay of the wires, the winding shaft has to lag the drive shaft.
You can see it on the sketch here: each successive layer must not cross the preceding layer at the edge where the wire changes direction. A very important point.

IMG_20210119_161838.jpg


The bobbin has a layer of double stick tape to insure the first layer stays snug on the bobbin.

firstlayer.jpg



The wire must be cotton or silk covered to create enough friction between windings, otherwise the wire slips off and creates a mess.
I wish you good luck with your coil winding endevour, and do not be discouraged when your junk basket starts to look like this:

pitstop.jpg

It is the norm, rather than the exception.

Cheers, Finn Hammer

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Richard Hull
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Re: A 50kV supply with 33mA drive ability

Post by Richard Hull » Tue Jan 19, 2021 5:02 pm

Really cool old basket winder mechanism. Even with the machine, slack in the mechanism forgiven, it is just another art that must be mastered, just like running a fusor. The box full of fails shows you have the stuff needed to get the job done. Adversity abounds in any thing worth doing.

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
Retired now...Doing only what I want and not what I should...every day is a saturday.

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Re: A 50kV supply with 33mA drive ability

Post by Frank Sanns » Sat Jan 23, 2021 2:00 am

Winding fine wire on coils is challenging. Too loose and they slide off. Too tight and they pull to the side as the layers increase and they slide off.

A solution that I have used with nearly 100% success is to spray the windings with some clear fast drying urethane or lacquer. Just enough to make it tacky and hold. I do this each time I get enough work into the coil that I don't want to loose the last portion of work. A light spray of the entire coil when you finish will make it look uniform.

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Re: A 50kV supply with 33mA drive ability

Post by Finn Hammer » Sat Jan 23, 2021 11:38 am

Frank,
Thanks for the tip. So you have a basketwinder too? Which brand is it?

I have used CA glue for the same purpose and I gather there is even prefabricated wire with a coating which can be made sticky, by passing it through a bath with solvent, but up to now, have not managed to procure any of it.
I am just at the end of restoring an old lathe,

IMG_20210119_145508[1].jpg

and when it gets operationable, I may try to make multi section bobbins, although I am not sure they will help me in any way, but just take up more space in the winding window. The ability to accomodate 2 separate windings on a single core really appeals to me, and this may not be possible with multi section bobbins, which tend to be wider and not so tall.

Cheers, Finn Hammer

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Re: A 50kV supply with 33mA drive ability

Post by Frank Sanns » Sat Jan 23, 2021 11:45 pm

Finn,

My wire winder was the two handed one. Early on I did use my father's small lathe but it was too powerful and I did not want to have the wire grab and pull my hand in or slice through it. The lathe was only

The biggest project I every did by hand was around 4 miles of 22 gauge magnet wire on an 18" phenolic tube. It was a pseudo Tesla coil but it really was a pulsed air core transformer. Easily 5 foot sparks with each pulse. Plenty of fine tendrils.

Well worth the effort.

My technique was to make wooden plugs for each end of the tube with a hole in the center. A brass rod ran the length. At one end was a V block for the rod to sit in. At the other end, it was bent to form a handle. Using gloves, I would guide the wire in single layer as my wife turned the crank. I think we finished in in around 4 non-consecutive nights. It was tedious and I learned very quickly the trick to pull the windings tight and tape after every several turns. Then before the tape was removed, I sprayed it down untaped areas with insulating varnish, Once it dried, I removed the tape and sprayed the entire coil. I figured a little more dielectric between the windings was a good thing.

Yours look mighty pretty. Wish I had one of those machines when I was making smaller coils. Unfortunately I did not have the finances or space for such things when I was working on them.

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