Joe Ballantyne Fusor v1.

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JoeBallantyne
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Joe Ballantyne Fusor v1.

Post by JoeBallantyne »

So after ~15 years since I first starting lurking on the site, ~10 years of being a registered user that posted very infrequently, 3+ years of attending HEAS gatherings, and 1+ years of being retired, I am FINALLY actually building my first fusor.

I am going to document the progress in this thread.

My plan is to start as small and simple as I can. Complexity and increased size will no doubt follow. Just like every other fusion project on the planet. :-)

Feedback and suggestions are always welcome.

It is fun to finally be building something.

Joe.
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Re: Joe Ballantyne Fusor v1.

Post by JoeBallantyne »

So here are some pictures of the chamber and cathode. Since the goal is to keep it as simple as possible, and get it running as quickly as possible, everything is off the shelf standard stuff, or repurposed items that can be easily acquired from Ebay, Amazon or Home Depot. The less custom construction required the better.

The chamber is built from 2 KF50 tees, 1 KF50 KF16 tee, 1 KF16 4 way cross, 1 KF50 butterfly valve, 1 KF50 viewport, 1 KF50 blank, 1 KF50 KF40 conical adapter, and 1 KF40 30kV feedthrough acquired from Joe Gayo, with of course the appropriate KF centering rings and clamps to plug it all together.

IMG_20220226_193546360.jpg
IMG_20220226_194332848.jpg

The cathode is just a 1.2 inch diameter stainless steel wire shaker ball bought from Amazon. (1 of a set of 6 (3 large, and 3 small) that cost ~$7) The cathode is connected to the feedthrough using a piece of 2mm stainless rod "drive shaft" and 3mm "drive shaft couplers" also purchased on Amazon. VERY high tech! NOT! :-) I don't expect it will work particularly well, but the goal for this iteration is not Q>1, it is first plasma, and then neutrons. If the Q ends up being 1e-10, so be it. Custom cathodes and Q improvements will come later.

IMG_20220226_180552680.jpg
IMG_20220226_193912256.jpg
Next I plan to get the vacuum pump system running and connected, followed by the high voltage supply setup. The last thing will be to get the deuterium gas supply system built and connected.

Joe.
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Re: Joe Ballantyne Fusor v1.

Post by Dennis P Brown »

Glad you are making a run. So far, a very nice start - through not a traditional chamber; certainly the vacuum system will require a bit of work - from a pump, then the high vac system/valves, and gauges. But the last items should be your neutron detection system. Of course, safety features added all during construction phases as needed are important.
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Re: Joe Ballantyne Fusor v1.

Post by Paul_Schatzkin »

Well, this is certainly exciting news, Joe.

And the photos are beautiful. It's gonna be quite a rig.

I'm glad we're getting things settled here so that (knock wood) those picture will be assured their posterity .

And congrats on the retirement. I find myself in a similar condition at the moment. I won't be building a fusor, but Iv'e got some stories to tell...

--PS
Paul Schatzkin, aka "The Perfesser" – Founder and Host of Fusor.net
Author of The Boy Who Invented Television: 2023 Edition – https://amz.run/6ag1
"Fusion is not 20 years in the future; it is 60 years in the past and we missed it."
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Re: Joe Ballantyne Fusor v1.

Post by Richard Hull »

Joe, I am glad you have leaped into the construction phase of your journey here. You are the beneficiary of years of fits and starts by many who have come before. You will surely enjoy the journey at all stages. You are wise to keep it simple with real vacuum components as this usually leads to less pain for the wallet and a much more likely successful effort.

I look forward to future reports and images of your progress.

Again I wish you well and all the best in your efforts.

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
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
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Re: Joe Ballantyne Fusor v1.

Post by JoeBallantyne »

Thanks Dennis, Paul and Richard for your kind words.

I'm currently working on getting a roughing pump up and running and connected to a vacuum gauge. I have 3 pumps I am working with right now, and unfortunately none of them are in a state where I can connect them to a vacuum gauge or any of my other vacuum hardware.

I have a Welch 1405 that is running, but I have no idea what kind of vacuum it pulls. I'm waiting on a KF40 to 20mm hose barb so I can connect the pump to the rest of the vacuum equipment I have. It has a hose barb on it, but I have no KFxx hose barbs at all at the moment. I have some I ordered already on ebay, but they may take a while to show up. I flushed the oil out of this Welch, and it at least runs OK.

I have an Edwards E2M8 I am also working on, but it is a 220V pump, and looks like it has a British motor in it, that wants to be run from 3 wires, one ground (yellow and green wire), one neutral (blue), and one hot (brown) that should be 220V RMS relative to ground and neutral. Of course I can't find any definitive documentation from Edwards that says whether it is OK to connect blue and brown to the pair of hot 240V lines I have access to in my house. (Hot water heater, dryer and stove all have 2 wire 240V connections.) Problem is that each of those wires is only 120V RMS relative to neutral and ground. When I did just that and plugged the pump into the dryer connection, I got NADA. No pop, no boom, no flash, no sparks, and no movement. Not even a sound. Not even a hum.

So, I then unplugged it, took off the side panel and tried manually moving the pump in the direction shown on the top. I could move it, but it would periodically get hard stuck. The oil inside was very dirty. So I manually rotated the pump for a few minutes, poured new vacuum pump oil in the intake as I did so, and then after a while, I drained the old oil which took a while because it was very dirty and thick. Put in new oil, and continued manually turning the pump over, about an 8th of a turn at a time or less. Eventually I got it to the point that it was no longer getting hard stuck as I turned it. (When It got stuck, I would back it up and then go forward again, and doing that would get it unstuck.)

So, now that it appears the pump is no longer getting stuck, I have to figure out what the proper way to wire a British 220V motor into 2 wire US 240V circuit is. I suspect I may be stuck having to using a transformer, so that I can make the hot line 220V relative to neutral and ground. It would be really nice if there was any documentation from Edwards that just told you what the right thing to do was, but I haven't been able to find it.

The last pump I am working with is an Ulvac 200V pump from a Joel electron microscope. It only has two wires as input, and given that it says 200V, not even 220V, I am reluctant to do anything with it until I can get it connected to a variac and run it at its nominal voltage. 240V vs 200V is just a little too much off, for comfort. Plus I don't really fancy connecting 2 hot 240V wires to a motor and nothing else.

So later today (its already very early Saturday morning for me) I will go try to dig up a transformer or two, and see if I can get any of these foreign single phase high voltage pumps to actually turn over. Why the whole world can't share the same electrical standards, I don't understand. (Well I actually do - its all about money and control and not invented here mentality, but those are all STUPID reasons IMO, for not just biting the bullet and standardizing across the board.) But once you have lots of incompatible expensive infrastructure built up, its not going to change. Oh well.

Hopefully later today I can get the Edwards spinning over, because that has a KF25 vacuum connector on it, so I could then get it connected to other hardware and see what vacuum it pulls, pull down my chamber, etc.

Joe.
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Re: Joe Ballantyne Fusor v1.

Post by Dennis P Brown »

I would suggest you wait to test your normal voltage Welch pump since they are good vacuum pumps. Also, such a pump should be the easiest to deal with since a repair kit should be available if it does have issues.

I do not think American 220 v (three phase) can be used for a 230 v (single phase) device (as you discovered - it will not turnover.) As you mentioned, a step up transformer is required - one that can handle the current load. Before running a pump that is 'sticking' I would suggest you dissemble it and make sure surfaces are fairly clean - this assumes you have ruled out the Welch pump. That is the safest method to clean a pump for service. Of course, it is possible to destroy gaskets so that does carry risks but if one is careful it isn't too difficult.
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Re: Joe Ballantyne Fusor v1.

Post by Richard Hull »

I can't imagine a ground wire path on the Edwards making any contact with any part of the motor windings. If it does that is not good. I have a 220 volt Edwards here in my lab and it works on a normal U.S. 220 volt outlet just fine. (I have several 220 outlets in my lab.) I have had it in plain view for sale at the last 3 HEAS conferences. It pulls to about 10 microns. However, no takers due to the 220 volt requirement.

Have you ohm checked the ground wire to the other motor leads? It should read open if it is a normal 220 volt motor. You should only read short from it to the motor's metal body.

You might check for continuity between the other two wires. You should read some low ohm reading. If not then you may have a stuck open or dirty centrifugal switch on the internal rotor or an open start winding.

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Re: Joe Ballantyne Fusor v1.

Post by John Futter »

Your pump will be fine on 240 volts two phase as used in the states
We use these pumps @ work and our power is a bit over volts due to the substation being 15 yards away from our lab so we get 240 instead of 230 anyway.
your pump being stuck is a sign of the sliding vanes NOT sliding ie gummed up hope fully you have not bent them they are made out of a phenolic type stuff.
rebuild kits are available for these pumps includes all gaskets and new vanes if you get the right kit
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Re: Joe Ballantyne Fusor v1.

Post by Richard Hull »

You need to get the motor running regardless of vanes. The 240 stock 2 lead and ground is the right connection and is what you need. Not turning? .... Motor problem.

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Re: Joe Ballantyne Fusor v1.

Post by Dennis P Brown »

The motor, as long as the case floats relative to the ground side of the motor coil's "grounding side" wire, then I guess two of the hot phases of the 220 would drive it. Is that how your pump works off the 220? Might be good to give some guidance on the wiring configuration for the 220 plug and clarify the grounding issues, maybe. I have not done this so am mostly in the dark on this issue.

If the Welch pump works, why not wait to test that and if it is good, that would be an excellent pump.
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Re: Joe Ballantyne Fusor v1.

Post by Rex Allers »

On the vacuum pumps. The old Welch pumps are great and take a lot of abuse before they become much below their specs.

I have a 1402 and it gets, at the input, around 3 micron. Your 1405 is smaller but may still be good in a fusor application.

I just made a post about converting the hose input on my 1402 to a KF-25. I suspect the input on your 1405 is the same part. Doing this mod requires access to a metal lathe and some courage.

FWIW, here's the link to my post.
Convert Welch Duo-Seal Hose Nipple to KF-25
viewtopic.php?p=94728#p94728
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Re: Joe Ballantyne Fusor v1.

Post by JoeBallantyne »

So, in some ways I made lots of progress today, but still failed at what I really wanted to get done, which was to get my chamber pumped down to a few microns.

I figured out why I got NADA on the Edwards E2M8 pump, it was because the 240V 2 wire circuit breaker in my panel going to the dryer was bad. I switched to a gas dryer about 20 years ago, and never used the dryer circuit, so didn't know the breaker was bad. I had another 30A 240 breaker in the panel for a water heater, which had also been switched to gas even before I bought the house, so I swapped the unused water heater breaker for the bad dryer breaker, and bingo, the E2M8 spun right up. Unfortunately the motor was squealing, so ran some oil down one of the 300mm long 2mm diameter stainless "drive shafts" I bought for connecting cathodes to feedthroughs to the actual motor drive shaft next to the bearing on front and back, let it sit for a little bit, turned it back on and the motor squealing cleared up.

So then I swapped the blank off on the inlet port for a Varian 531 Thermocouple connected to a Varian 801 display, turned the pump back on, and was immediately disappointed. Pump pulled down to about 200 microns, and then just sat there. Now granted I haven't run it for several hours and then rechanged the oil, but given the amount of exhaust coming out the exhaust port, even when the gas ballast is fully off, I suspect it may have a leaky seal around the drive shaft. I suppose I could let it run for a few hours, come up to temperature, and see if it performs better. But 200 microns right off the bat seems pretty bad.

Turns out I found another Edwards E2M18 that actually had a US motor on it, setup for 115, so I tried that one, it also appears not to pump below 200 microns, and although the motor runs fine for a few minutes it eventually gets a chatter in it, and oiling the shaft does not appear to resolve the issue. (If it isn't already obvious, 15+ years of collecting vacuum and other fusor related equipment, means I actually have quite a lot of stuff.) None of which appears to work very well. :-)

I also tracked down a large Superior Electric 240V-280V 40A variac that appears to be configured for 120V in, and 0-140V out, as well as a 120/240 500KVA transformer, but the 120/240 transformer didn't have enough oomph to get the Joel pump to turn over. I got a hum, but no motor turning. I suppose I could just directly wire the Joel to my 240, but I really don't want to ruin it, by running it over voltage. It is spec'ed for 200V. I probably need at least a 1200KVA 120/240 transformer, but I don't have one.

As far as the Welch 1405 goes, I have ordered a KF40 hose barb that should let me get connected to it, as well as a rather pricey KF25 adapter made specifically for Welch pumps with a 3/4" 20 thread, which this pump supposedly has - and is what the 7/8 hose connector on the pump is screwed into. (Per the old 1970's Welch pump manual which you can find online as a pdf.) So, when one or the other of those items arrives, I can then figure out whether that pump's vacuum sucks too. (ie: sucks, as in doesn't actually suck... just like the 2 Edwards pumps.) I'm hopeful that it will be better, but so far my experience has been that surplus pumps, were surplussed for a reason...

It is conceivable that my 531 TC, or the 801 display are off as well. I have a second set of both, so will see if they agree with each other on the Edwards pumps that I can measure vacuum on.

I really don't want to spend a lot of time doing a pump or motor teardown/rebuild. So until I have exhausted my full inventory of pumps, I will keep just trying to find a pump I already own that works reasonably well. I would be happy if I can find one that gets me down to 2-5 microns.

We'll see.

Joe.
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Re: Joe Ballantyne Fusor v1.

Post by JoeBallantyne »

Rex, thanks for the pointer to the mod for the 1405 hose barb input. Unfortunately I do not own a lathe, nor do I currently have access to one, so that is not an option for me. You can buy a KF25 adapter that should just screw right into the 3/4" 20 tapped hole for about ~$80 on ebay, so that is what I did. It hasn't arrived yet. When it does, I will report on how well it works or not.

Joe.
Last edited by JoeBallantyne on Sun Mar 06, 2022 5:49 am, edited 2 times in total.
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Re: Joe Ballantyne Fusor v1.

Post by JoeBallantyne »

John Futter, do you think that just connecting the Joel pump directly to the 2 wire 240V I have in my house would be OK, or is 200V too far off to be worth the risk. The Edwards did work fine, but it was a 220V motor running at 240. The Joel pump looks like it is in pretty decent condition, so I really don't want to ruin it. Since if I can get it working at its nominal voltage, and it pulls a good vacuum (<3 microns) I will just use it.

Joe.
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Re: Joe Ballantyne Fusor v1.

Post by JoeBallantyne »

Dennis, the plug in my laundry room for the dryer is an old style US 230-240V 30A plug. On each side of the top of the plug it has two slots for slanted wide, thick prongs, and on the bottom in the center a hole for a prong that looks like the left and bottom side of a square. The prong itself is bent 90 degrees.

The bottom prong is neutral, the top two prongs are each 120V RMS, but 180 degrees out of phase, so that the voltage difference between the two wires is 240V RMS. Evidently the 240V wires typically come off a center tapped pole pig transformer, where the center tap is neutral and is grounded.

The old style plug I have has no 4th prong for the earth ground wire, just the single neutral connection. New 240V plugs all have 4 connectors in them so you can have an earth ground in addition to neutral and the hot line1 line2 wires.

Turns out the Edwards E2M8 runs just fine connecting blue wire to one of the 2 hot 240 wires, and the brown wire to the other of the hot 240 wires.

Per Richards suggestion I tried measuring the impedance from the blue and brown wires to the case, and it was an open circuit. No connection between the wires driving the motor and the case.

Joe.
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Re: Joe Ballantyne Fusor v1.

Post by Richard Hull »

Info for newbies monkeying with home electrical systems.

Ground is neutral at the breaker box that feeds the home. The other two wires coming in from the power company are 120 volt lines referenced to ground/neutral at the box. A second demanded driven ground at the house also goes to the breaker box. Just remember that neutral wires in all homes is are at ground potential back at the breaker box where it's case is also ground. All of this is modern by comparison to the old two wire systems where neutral was often looked at as ground. Ground was run separately not long after WWII for safety going to all metal bodied tools and appliances.

In general all 240 volt appliances, motors, etc., never reference internally to ground or neutral. The grounded metal case of 240 volt items protect against either of the 120 volt hot lines from energizing the case.

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Re: Joe Ballantyne Fusor v1.

Post by John Futter »

Joe
I weould try the 200 volt pump on 240
if it gets hotter than you can touch after some time running ie half an hour thewn you will have to get a 240 volt to 40 transformer and connect it in buck in series with the input in your case 2 x 20 volt windings would balance the load to your local transformer but that is not necessary unless you have a 20 0 20volt 5 amp transformer lying around
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Re: Joe Ballantyne Fusor v1.

Post by JoeBallantyne »

An update on the current state, plus a few pictures.

I decided that I would run the Edwards E2M8 pump for several hours today. As prep, to make absolutely sure it would be OK, I oiled the motor bearings again, as well as the bearing in the center plate of the pump, and where the drive shaft enters the pump body. I used clean vacuum pump oil, as it is high quality non detergent oil, and by definition has a very low vapor pressure. I then powered it up, and pretty much let it run all day long. It is still running as I write this. The motor eventually got quite warm, but not to hot to touch, and the pump was quite a bit cooler than the motor, but also warm. The motor bearings were much cooler than the outer cylindrical shell of the motor housing.

Since I had another Varian 531 thermocouple, as well as another Varian 801 gauge, I put a KF16 cross on the pump, and connected both of the 531 TCs and 801 gauges to the pump. To my surprise I got VERY different readings from the second TC. Instead of reading ~200 microns, it showed the pressure at closer to 40 microns. I then switched which TC was connected to which gauge, and the readings on each gauge stayed pretty much the same. The gauge that had read 200 now read about 205 microns, and the gauge that had read 40 now read 35 microns. That was great news, as it means that the TCs themselves are in pretty close agreement. One reads about 5 microns higher than the other. Neither of the 801 gauges has been calibrated, or zeroed, since that requires that I get the pressure on the TC down to less than a micron, which I currently can't do. Clearly one of the gauges is off quite a lot. Which one I can't determine yet.

However, I'm feeling better about the pump, as I am hopeful that the lower reading is closer to the actual true pressure, than the higher one. I do have a capacitance manometer, that I may attempt to get up and running, if I can find or acquire the appropriate cable. I can use that to determine which of the TC readings is closer to the proper pressure (most likely they are both off at least slightly), but I am hopeful that the higher reading gauge will prove to be off by a lot.

Next I added a connection from my vacuum chamber to the Edwards pump and pumped down my chamber for the first time. It went down to about 50 microns per the lower reading gauge, pretty quickly. After an hour or so of pumping, it went down to the 35 micron to 40 micron range.

I valved off the pump to see if I had a leak, and the pressure in the chamber with the pump valved off was pretty stable. It rose about 10 microns or so in a minute. So not perfect, but I haven't done any glow cleaning yet, and the parts were not cleaned with solvent before I assembled them, so I am sure there is outgassing going on in the chamber. I did not make any effort to not leave fingerprints on or inside the chamber, hence my fingerprints are pretty much all over it, And I'm sure there is oil from my hands on some of the flanges and centering rings as well. In addition I live in the Seattle area, and so there is a lot of moisture in the air, and I am sure there is a lot of adsorbed water vapor all over every inch of the inside of that chamber.

I was happy with the fact that there were no major leaks. KF fittings really do work very well. They are easy to use and assemble, and they do the job. Plus you can reuse the centering rings as much as you please. Unlike copper conflat seals.

Here are some pictures of the chamber, TC gauges and vacuum pump setup. Note that the only useable 240V outlet I have in my house is in the laundry room, and I need to plug the pump into that. So you can probably surmise what is underneath the tablecloth. :-)

Here is the Edwards E2M8

IMG_20220306_205735553.jpg

Here is the whole current setup

IMG_20220306_205649634.jpg

Here are closeups of the TC gauges showing the disparate readings. The first shot was just before closing off the vacuum pump from the chamber, the second shot is two minutes later after the pressure has risen, and the last shot is a few seconds after reopening the valve when the chamber has pumped down again.

IMG_20220306_205944676.jpg
IMG_20220306_210201375.jpg
IMG_20220306_210225117.jpg

Joe.
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Re: Joe Ballantyne Fusor v1.

Post by Richard Hull »

Give the TC gauges an even break! Wash out each tube with a solvent like MEK/Acetone. Rinse two or three times sloshing the filled tube around.
This should warrant there is little filth and old oil on the thermo couplet junction.

Next, you know that zeroing is a must. You are off to a good start is you measure the current draw to the heater it has a fixed value to start with and this is in the manufacturers spec sheet. These are 531 tubes. In the vacuum post in the FAQs, I give a table for design currents for many TC gauge tubes. A good tube, when zero'd will be very close to this current value.

viewtopic.php?t=14378

I note that the 531 is a filthy current hog compared to most other TC gauge tubes needing 163-165ma of heater current. If you can, put an ammeter in series with the heater. Take the gauge tube as low in vacuum as you can and use the zero pot (current control) to set the meter to this rated current and you should be close to the real reading, assuming the tubes are good and clean. Cleaning the tubes may solve all issues by itself.

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Fusion is the energy of the future....and it always will be
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Re: Joe Ballantyne Fusor v1.

Post by JoeBallantyne »

Richard -

I'm pretty sure that the meter on the right in the pictures is just bad. It won't go much under 200 microns period. I had a couple supposedly brand new old stock 531 tubes I bought on ebay, and they each came in a little Varian box, and swapping one of those tubes in doesn't make almost any change to the readings on either gauge/meter. I'm not real keen on rinsing the tubes out with Acetone, especially not the "brand new" ones. If the tubes I was using looked trashed/dirty I would try rinsing them out in a heartbeat. These don't look like they need a rinse. Granted, one can't really tell, and they could have oil or other contaminants up in the TC, but I want to try a few other things to figure out the pressure (like using a capacitance manometer) before I do any rinsing.

One of the reasons I think that meter on the right in the pictures is bad, is because after leaving the chamber valved off from the pump, but still under vacuum last night (Sunday 3/6/2022), this morning the gauge on the left was reading about 500 microns pressure, and the gauge on the right was above the ATM mark. But I then opened up the chamber, and it was definitely still under vacuum, as there was the normal hiss of air going in, and the left hand gauge rose up to dead center of the ATM mark on the gauge. The gauge on the right almost didn't move at all.

So while I still have no idea if the pressure reported by the LH gauge is actually correct - since I don't know if I have a good enough vacuum to zero it, I'm pretty confident it is working much better than the gauge on the right.

I will at some point get a vacuum setup that pulls submicron, and at that point I will zero the TC gauges.

Joe.
Last edited by JoeBallantyne on Tue Mar 08, 2022 6:48 am, edited 1 time in total.
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Re: Joe Ballantyne Fusor v1.

Post by JoeBallantyne »

So, today, Monday 3/7/2022 was a productive day fusor wise, and I got first light of plasma! That was a very satisfying sight.

Pictures of that will come in a later post, but lets start at the beginning...

I received some of the things I ordered on ebay recently. One was a couple of sets of rubber stopper sets of sizes 00 up to 8. One set with holes and one without any holes. I got them because I read, I think in the Welch pump documentation, that one way to quickly measure the pressure on a pump was to use a rubber stopper with a hole in it, and screw the TC gauge into the top of the hole. Then stop the intake of the pump with the stopper, and run the pump and measure the pressure.

So, I tried that with the Welch pump, and the technique seemed to work just fine. That pump doesn't pull down nearly as fast as the Edwards E2M8, but then it is a lower capacity pump. After a few minutes of pumping it got down to about 40 microns, and some time after that it got down down to 30 microns as measured on the TC gauge that was on the LHS of the fusor system pictures. (The TC gauge I have that appears to not be busted.)

So, the Welch 1405 pump works, but it doesn't pull a significantly better vacuum than the Edwards E2M8. I have seen the Edwards pull the chamber down to about 20 microns after the chamber sat all night long under vacuum, and on first pump down after it sat, it got down to 20, and then the pressure in the fusor slowly rose again to about 40 microns.

A picture of the welch and its initial vacuum measurement:

IMG_20220307_150813508.jpg

Joe.
JoeBallantyne
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Joined: Tue Jul 20, 2010 4:08 pm
Real name: Joe Ballantyne
Location: Redmond, WA

Re: Joe Ballantyne Fusor v1.

Post by JoeBallantyne »

One of the other ebay purchases that showed up today, was the special KF16 Welch 1405 intake that I ordered. I was going to swap it on first thing, but the hose barb on the Welch is on REALLY REALLY tight, and I thought, well, I will measure the pressure first with the rubber stopper method, and then if it looks good, I will swap the intake, and remeasure the pressure using the new KF16 part.

However, since the pressure was not much better than my other pump, and since I know I have a brand new Welch pump (no motor, just the pump head) of some unknown model, I thought I would wait to use this fancy little KF intake, in case it will fit on the other pump head. I don't recall at the moment what kind if intake if any is on the new pump, and I don't know the model, but it looks like about 10"x"12"x12", so it might be a 1402 like Rex has. Not sure.

In any case, for now the Welch 1405 is going to stay as is, with its hose barb, and I will probably end up using it as a backing pump with either a diffusion pump or a turbo in front of it.

I was very pleased with the KF16 intake part. It looks very nice, and came with 2 extra gaskets.

Here is a picture, that includes info on the seller, who appears to also be on Amazon, as the package arrived with an Amazon receipt and in an Amazon package, even though I ordered it on Ebay!

IMG_20220307_184416696.jpg

Joe.
JoeBallantyne
Posts: 326
Joined: Tue Jul 20, 2010 4:08 pm
Real name: Joe Ballantyne
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Re: Joe Ballantyne Fusor v1.

Post by JoeBallantyne »

Now for the good stuff...

I spend a good part of the day (Monday 3/7/2022) setting up a simple, pretty inexpensive, medium voltage power supply on the fusor. I had previously verified that the key parts of it were capable of outputing the claimed voltage.

The first piece of the supply is a Universal Voltronics BPE 22-5.5 DC power block capable of putting out 22kv at 5.5ma. Not that high a voltage, and definitely not too much current. But at 121 Watts it should be able to at least light up a plasma at lower than its rated voltage, and I am hopeful that with my Neutron detection hardware, I will be able to even measure neutrons. We shall see. This power block was purchased on Ebay for about $150.

The block is connected to a clearly vintage 7.5KVA variac that was likely purchased from UW Surplus as part of a large lot of variacs and other assorted stuff. The variac will put out 0 - 140V on the secondary when driven with stock 120V on the primary.

I verified that I could get out the rated voltage from the BPE using a couple Pomona HV DC probes. One that goes up to 15KV, and another that goes to 35KV. The Pomona probes only measure positive voltage so I can't use them in the fusor configuration because the HV lead that needs measuring is at a negative potential. The nice thing about the Voltronics supply is that it has 2 HV leads coming out of it one positive and one negative so you can configure it to be either a positive or negative supply by just grounding the opposite polarity lead. These power blocks are used as a component in stand alone power supplies built by Universal Voltronics that have meters, and a variac, output polarity switching, etc.

The Voltronics has 8 solderable pins in a circle on the side opposite the HV leads, and I could not find documentation on the pinout. I am sure that you can change how the supply operates by varying what you connect to those pins. Fortunately the supply I bought was prewired, and appears it was wired so that it puts out its full rated specs on 120V in. The wiring it came with also had a fuse block in the 120V supply line.

After getting everything setup on the fusor, I set the variac to about 20 on its dial - which corresponds to about 20V RMS AC input on the BPE, which should make it put out about 3.5kv. I switched it on, and BINGO, plasma immediately lit up in the fusor. I was surprised, but very happy.

Interestingly the plasma would pulsate on and off, and after little while it extinguished, and I had to raise the voltage up to 25 on the variac to get it to light off again. Eventually I had to raise the variac up to 40 to get the plasma to light off, 40 should correspond to about 7.3kv (1/3 of the output as 40V RMS is 1/3 of 120V.) At that voltage I could switch the variac output on and off, and the plasma would just go on and off with it. It was very cool.

Now for the requisite eye candy...

The Univeral Voltronics BPE 22-5.5 attached to the fusor.

IMG_20220307_172039804.jpg

The very vintage variac, with (I know) a cracked outer sheath on the input power line. Note that I measured with a multimeter to be absolutely sure which of the plug prongs on the output plug was neutral and which was hot, and they are labeled N and H with a sharpie on the variac body itself. In addition, I marked N and Hot on the plug of the white cord so there would be no mistake about how it should be plugged in. Granted, it would be better to use a 3 prong power cord plugged into the variac. Which will happen in a future iteration.

IMG_20220307_172103764.jpg

The whole system with plasma lit up inside the fusor.

IMG_20220307_171929577.jpg

Finally a close up of the plasma. The picture doesn't do it justice, as when you look at it with your eye, the bright plasma center is much smaller than what shows up in the picture. What you see with your eye is a little dot about 1/8th of an inch in diameter in the exact center of the wire circle. It does NOT fill up the entire center like the picture shows. What the eye sees is much cooler.

IMG_20220307_171214260.jpg

Joe.
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Dennis P Brown
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Re: Joe Ballantyne Fusor v1.

Post by Dennis P Brown »

A few words - first, nice start. You're advancing. Second, be aware that micron gauges (as I've had experience with) can be a bit off. As such, your pumps could be doing better then you think. In any case, both will work with a turbo or diffusion pump even if those values are precise. I could ask about pump oil and condition but seriously, not critical if you are below 50 microns (though those pumps should get to under 5 microns no problem.)

You should aim to measure your fusor's voltage, current, and vacuum and submit for the plasma club. That is a good first step here and your basically there with only a minor bit more effort.

Do be aware that as vacuum improves the required voltage for a plasma to remain "lit" goes up so those results you are seeing follow.

In the pic of your plasma, you have two TC gauges (located on the same stem) and they are showing wildly different values - one in the 30's and the other in the 250's?

Finally, and as always, be careful with that supply because the voltage in those ranges are dangerous. Even for a 'mock' setup, a star ground system is essential.
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