Search found 919 matches

by Rich Feldman
Tue Jan 21, 2020 7:09 pm
Forum: Fusor Construction & Operation (& FAQs)
Topic: Vacuum Chamber Construction
Replies: 33
Views: 16183

Re: Vacuum Chamber Construction

I can attest that sunburn is a risk if you skip the gloves and long-sleeve shirt, buttoned up at least as far as the bottom of welder's mask. Even TIG welding can occasionally pop & launch a shower of sparks, actually incandescent droplets of steel which you don't want to fall into your shoe or pock...
by Rich Feldman
Tue Jan 21, 2020 7:01 pm
Forum: High Voltage - Fusor Input Power (& FAQs)
Topic: Help Finding a Transformer Core Part
Replies: 5
Views: 266

Re: Help Finding a Transformer Core Part

I think any core with flat laminations of the right thickness, at least as wide and long as the missing parts, will do. They aren't hard to take apart and delaminate, even if welded. It might take some looking around to find a suitable transformer to cannibalize. The MOT I checked (a relatively smal...
by Rich Feldman
Mon Jan 20, 2020 6:55 pm
Forum: High Voltage - Fusor Input Power (& FAQs)
Topic: Help Finding a Transformer Core Part
Replies: 5
Views: 266

Re: Help Finding a Transformer Core Part

Sorry to hear about the transformer damage. I've received damaged goods via UPS and Fed Ex as well as the USPS, and often felt the problem started with inadequate packing. You're lucky to have received your NST in one piece, if it was shipped without a wooden crate or double boxing or large pieces o...
by Rich Feldman
Wed Jan 15, 2020 8:35 pm
Forum: High Voltage - Fusor Input Power (& FAQs)
Topic: Power Supply from an "interesting" XRT
Replies: 8
Views: 586

Re: Power Supply from an "interesting" XRT

Good work so far, Pablo! Thank you for sharing. >>one "start of winding" is connected to the core. However the other winding is odd because it has its "start of winding" connected to the core, however it has two HV outputs. That detail is like my similar-size XRT, except mine has three HV outputs. E...
by Rich Feldman
Mon Jan 13, 2020 10:50 pm
Forum: High Voltage - Fusor Input Power (& FAQs)
Topic: Neon sign transformer power: a new look
Replies: 25
Views: 10228

Re: Neon sign transformer power: a new look

Read Richard Hull's "neons" document, in a recent FAQ. Or read this thread and scale the numbers for your NST nameplate. Too bad if pictures can't be seen without opening them. Check images with IV in name, near top of second page (?). Or make a kV meter and 20 mA dummy load, which you need anyway, ...
by Rich Feldman
Mon Jan 13, 2020 6:49 pm
Forum: Items For Sale
Topic: Rich Feldman's store. Today's feature: beryllium sheet
Replies: 9
Views: 758

Re: Rich Feldman's store. Today's feature: beryllium sheet

Battery-powered bandsaw did the job for first square, earmarked for Richard. A little WD-40 on the top surface kept some of the sawdust under control. Clean up with brush and dustpan, before a vacuum cleaner with very fine filter. Will wear a dust mask next time. be_corner.JPG . Can't do an adjacent...
by Rich Feldman
Sun Jan 12, 2020 2:13 am
Forum: Items For Sale
Topic: Rich Feldman's store. Today's feature: beryllium sheet
Replies: 9
Views: 758

Re: Rich Feldman's store. Today's feature: beryllium sheet

Drew a line and took a few strokes with an X-acto saw, then with a regular hacksaw. The indentation is visible, but very small. Plan B is to borrow a wet tile-cutting saw from my brother, next time we meet. Any recommendations about diamond-embedded round blades, 4 to 5 inch size, that cut kerfs nar...
by Rich Feldman
Sat Jan 11, 2020 11:52 pm
Forum: Neutrons, Radiation, and Detection (& FAQs)
Topic: How hazardous is BF_3
Replies: 1
Views: 204

Re: How hazardous is BF_3

Hi Ryan. Good thing to wonder about. Easy to get scientific in the Internet era, but beware of fake news. :-) The BF3 pressure in my proportional counter tube is a little below atmospheric. So if a small crack or hole appeared, the stuff would not spew out. Total pressure inside and out would rapidl...
by Rich Feldman
Sat Jan 11, 2020 4:13 am
Forum: Items wanted
Topic: 0-200 V, 200 V Pulsed Power Supply Units
Replies: 2
Views: 276

Re: 0-200 V, 200 V Pulsed Power Supply Units

Yeah, and the 22 amp supply must be for thyratron filament.
You can get that almost for free, as alternating current, by rewinding the secondary of a MOT (or any other transformer of at least 150 VA size).
by Rich Feldman
Sat Jan 11, 2020 2:00 am
Forum: Items For Sale
Topic: Rich Feldman's store. Today's feature: beryllium sheet
Replies: 9
Views: 758

Re: Rich Feldman's store. Today's feature: beryllium sheet

Be sheet thickness near corners a, b, c, d: 0.0650, 0.0660, 0.0665, 0.0660 inches. 1.65, 1.67, 1.71, 1.68 with digital caliper set to millimeters. This is the real stuff, which came to me via ebay near end of 2012, with an original Brush Wellman paper label that is around somewhere. 2 x 2 inches I c...