Search found 1055 matches

by Rich Feldman
Sun Sep 20, 2020 10:28 pm
Forum: High Voltage - Fusor Input Power (& FAQs)
Topic: Diy high voltage probe
Replies: 4
Views: 93

Re: Diy high voltage probe

Nice work there; thanks for demonstrating by doing. It's OK to talk about using parts above their ratings. This is no worse than using MWO diodes to rectify a NST output, when operating PRV can be more than 21 kV. Electrical component abuse is a popular theme on Tesla coil forums. All are cases wher...
by Rich Feldman
Mon Sep 14, 2020 8:28 pm
Forum: Interesting Links
Topic: Possible Life in the upper atmosphere of Venus
Replies: 1
Views: 244

Re: Possible Life in the upper atmosphere of Venus

So Venus atmosphere balloon probe joins the throng of applicants competing for space probe funding. Other missions include the big metallic asteroid, Titan lake floater, Enceladus and Europa, etc. One that got approved, as discussed here a year or so ago, is the Titan lander / quadcopter that can fl...
by Rich Feldman
Sun Sep 13, 2020 7:37 pm
Forum: Fusor Construction & Operation (& FAQs)
Topic: Restarting Efforts on Demo Fusor II
Replies: 25
Views: 1766

Re: Restarting Efforts on Demo Fusor II

Kuri is the same brand as my spiral hose. John's a practiced expert with vacuum stuff, and I'm lately just a pretender. Have never set up any diffusion or turbo pump with a backing pump. Need to clear a path to a work space for vacuum gear, not touched (except for opportunistic acquisitions) in abou...
by Rich Feldman
Sun Sep 13, 2020 7:03 pm
Forum: Fusor Construction & Operation (& FAQs)
Topic: Restarting Efforts on Demo Fusor II
Replies: 25
Views: 1766

Re: Restarting Efforts on Demo Fusor II

Very cool, Ed. Back to vacuum gear and foreline connections, I finally dug out the vacuum hoses here. The ID of spiral-reinforced hose is 1/2 inch, and of thick rubber hose is a little less than 3/8 inch. Too small for the need you mentioned, but they are free to anyone who wants to pay the postage....
by Rich Feldman
Sun Sep 13, 2020 6:30 pm
Forum: High Voltage - Fusor Input Power (& FAQs)
Topic: RF superimposed on HVDC
Replies: 3
Views: 391

Re: RF superimposed on HVDC

You need to start by specifying details like the RF impedance of the HV load, HV power source, and RF signal source. The series capacitor on RF-input branch obviously needs to hold off some kV, and will conduct glitches from HV arcs and sparks back to the RF signal source. The traditional inductor o...
by Rich Feldman
Sun Sep 13, 2020 6:12 pm
Forum: Interesting Links
Topic: 4hv
Replies: 3
Views: 149

Re: 4hv

Hello, Cai. That forum used to be a lively place, but has almost dried up in the last year or two. After some necessary software update broke the easy ability to embed pictures, and put an exceptionally cumbersome captcha as a hurdle for every log in. I think the administrators are weary after more ...
by Rich Feldman
Mon Sep 07, 2020 12:16 am
Forum: High Voltage - Fusor Input Power (& FAQs)
Topic: Questions about HV rectifier
Replies: 35
Views: 1065

Re: Questions about HV rectifier

To "Stop the ground loop from damaging equipment" sounds like a worry from someone who would be hard pressed to explain the problem. You referred to a video that mentioned destruction of a turbo pump, but was that because of a ground loop? I think there are two factors that matter in groundING topol...
by Rich Feldman
Sat Sep 05, 2020 2:43 am
Forum: High Voltage - Fusor Input Power (& FAQs)
Topic: Questions about HV rectifier
Replies: 35
Views: 1065

Re: Questions about HV rectifier

>>I'm thinking about probably ground one of the HV leads together with all the grounding points and utilise only one HV lead with one diode for negative HV supply. >>That to me seems more correct however it now really becomes a 'half wave rectified' situation where half of the energy is wasted.........
by Rich Feldman
Fri Sep 04, 2020 4:33 pm
Forum: High Voltage - Fusor Input Power (& FAQs)
Topic: Questions about HV rectifier
Replies: 35
Views: 1065

Re: Questions about HV rectifier

Yay for schematic diagram. Is the transformer core electrically inaccessible, insulated by epoxy from the transformer's mechanical attachment details? Before we discuss current metering, please show (e.g. with a highlighter pen) one complete, closed loop for current in the HV circuit, at an arbitrar...
by Rich Feldman
Fri Sep 04, 2020 12:18 am
Forum: Vacuum Technology (& FAQs)
Topic: Who has the largest chamber? Any pics?
Replies: 6
Views: 583

Re: Who has the largest chamber? Any pics?

The metal bell-jar chamber in pictures reposted by Richard appears to have coolant pipes on the outside. Reminds me of one in somebody's garage one county away from me. Used for evaporating reflective and corrosion-resistant coatings onto amateur telescope mirrors. The big NASA chamber (at which fac...