From: "Terrell W. Fritz"
Date: Tue, 29 May 2001 19:43:09 -0600
Subject: Re: [TSSP] Topics on non-linear effects
Hi Bert, I have checked out the Ross Engineering VD120 and the Jennings Model 13200. They seem to be the sort of things that would be good for this. Probably a 1000:1 divider at 200kV peak would be nice. I assume the new prices are enormous especially from Ross. I think I have worn out my welcome with Jennings ;-)) It is probably not too hard to make an oil filled homemade version. I have the precision Bertan that goes to 50kVDC that could simply arc to ground to make the voltage step for calibration. http://hot-streamer.com/TeslaCoils/MMCInfo/GeekCaps/HVTest.jpg I would be very interested in any design information or tips for such things. Cheers, Terry At 07:36 AM 5/29/2001 -0500, you wrote: >Terry, > >Ross Electronics and Jennings make similar units, using either compressed >gas (advantage: no X-Rays) or vacuum capacitors for the HV cap(s). Do you >have any idea of the expected standoff voltage required? I have a couple of >Ross units, one rated at 15 kV (off Ebay!) and the other for 60 kV >(untested - just picked it up at the Dayton HamFest, looks a bit beat up >though). > >It might be possible to make an air insulated HV capacitor, or use a chain >of vacuum caps with grading rings for the HV section. If you want to try >"rolling you own", I have some design information that might be useful. As >you indicate, the key would be in calibrating the thing. Assuming you could >prevent corona leakage, it may be possible to calibrate it by using a >precision HV DC supply (say 5 or 10 kV) and then "pulsing" the output to >the divider via a HV SPDT vacuum relay, driving the divider input to either >the supply voltage or ground. > >-- Bert -- >-- >Bert Hickman >Stoneridge Engineering >Email: bert.hickman@aquila.net >Web Site: http://www.teslamania.com > > >"Terrell W. Fritz" wrote: >> >> Hi Paul, >> >> Capacitive voltage dividers may be the way to go. Something along the >> lines of the $800 Pearson: >> >> http://www.pearsonelectronics.com/Pages/Capacitive_Voltage_Divider.html >> >> Unfortunatly, there were none on E-bay... ;-) >> >> They have the advantage of being calibrated out of the box (5%) and all the >> thinking is done. They have 18pF of load. >> >> Most places seem to roll their own: >> http://www.uni-stuttgart.de/ieh/forschung/einrichtungen/v_general.jpg >> http://www.uni-stuttgart.de/ieh/forschung/einrichtungen/v_Teilentl1.jpg >> >> The problem is by the time you get all the electrostatic shields and >> terminals big enough not to arc, the load goes up too high. However, they >> are basic physical devices with few tricks and the outputs can be clamped >> heavily and such for protection. Calibration is not trivial either. I'll >> think on it. >> >> The plane wave antenna is another possibility but it is a wide area device. >> Perhaps it could be aimed through a tunnel or antenna like array to hit a >> small spot... >> >> I used to repair voltage dividers on 375kV power line equipment (live >> ==:-| ) but I don't think those types would be any good at high-frequency. >> >> Cheers, >> >> Terry >> >> At 11:37 PM 5/28/2001 +0100, you wrote: >> >Terry, All, >> > >> >Some preliminary notes on your CW brush discharge current >> >measurements. >> > >> > http://www.abelian.demon.co.uk/tssp/tfcw260501/ >> > >> >Next step would be to determine what the discharge impedance >> >is, and how it varies with the steady state voltage. But an >> >essential prerequisite is a means to reliably capture the >> >peak topvolts value. >> > >> >Without this, we can't establish a pattern for brush discharge >> >loadings, nor can we confirm ET6.12 predictions of breakout >> >voltage. So now would be a real good time for budding inventors >> >out there to get cracking. >> > >> >Cheers All, >> >-- >> >Paul Nicholson, >> >Manchester, UK. >> >-- >
Maintainer Paul Nicholson, paul@abelian.demon.co.uk.