From: Bert Hickman
Date: Tue, 29 May 2001 07:36:18 -0500
Subject: Re: [TSSP] Topics on non-linear effects
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.