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RE: The Geek Group High Voltage Capacitors, making a HV switch, (fwd)
Original poster: Steven Roys <sroys@xxxxxxxxxx>
---------- Forwarded message ----------
Date: Wed, 8 Nov 2006 00:44:45 -0800
From: Jim Mora <jmora@xxxxxxxxxxx>
To: 'High Voltage list' <hvlist@xxxxxxxxxx>
Subject: RE: The Geek Group High Voltage Capacitors, making a HV switch,
(fwd)
Hi Jim, Bert and et al,
So what is a safe distance BTW components or more directly Buses with
rounded edges or Hard copper pipe to go out and make a return path for a
wire blow?. I seem to remember 40KV/in. I have the break down chart
somewhere but that deals in needle points and spheres.
I have read that Ed Wingate does a similar configuration as this: He uses a
mongo knife switch. What would be a safe handle length for a charge, open
(the scary one), and bleed down using a reconstructed knife switch with four
copper poles tied together on each side of center and moved to a larger arc
space, (phenolic and G10 base) and I am talking feet for the handle,
sideways, with baffles. I have 5 100K ceramic 12"x1 1/8" Shallcross 150C-
one each would maybe be enough. Current limit the PS, bleed down the
remaining charge or be able to do a full bleed in an emergency situation
without welding the switch.
The switch would be in the center position (disconnect to the PS EXCEPT to
the 40+KV caps for fire). This would be mounted sideways, the HV return
would be behind it. The main discharge is much like Bert's Switch. Two 2"
brass dowels and a 2" bore 4 inch movement single stage Pneumatic actuator.
I plan to back off of from this event. I have a portable air tank and a hand
discharge switch that I would operate from several feet away using Tygon
tubing and the tank by my side. Should wake up a crowd, yes?
The handle to the knife switch raises my hair a bit. What is your
recommendations. I would rather not automate it as it is for demonstration
and people can visually see what is being done. What do line man wipe their
"Jesus" sticks with. Mineral oil, silicone? I was thinking of making a 1.5"
schedule 40 three to four feet long stick and caping the user end, adding an
internal baffle on the knife switch handle end. Near the user would be 3
increasing in size exterior baffles.
Your thoughts Please?
Thanks Jim Mora
Now would be a good time to make this handle as the Santa Anna's are
blowing, its hot, and the humidity is wayyy low. Maybe seal the outside and
inside with polyurethane or HV laquer?
-----Original Message-----
From: High Voltage list [mailto:hvlist@xxxxxxxxxx]
Sent: Sunday, November 05, 2006 4:37 PM
To: hvlist
Subject: Re: The Geek Group High Voltage Capacitors, making a HV switch,
(fwd)
Original poster: Steven Roys <sroys@xxxxxxxxxx>
---------- Forwarded message ----------
Date: Sun, 05 Nov 2006 06:26:58 -0800
From: Jim Lux <jimlux@xxxxxxxxxxxxx>
To: High Voltage list <hvlist@xxxxxxxxxx>, hvlist <hvlist@xxxxxxxxxx>
Subject: Re: The Geek Group High Voltage Capacitors, making a HV switch,
(fwd)
>
>The short circuit energy in these capacitors cannot be adequately
>described in an email. They will not give you a second chance... never,
>ever, forget this.
>
>Bert
>--
Truly. Charged capacitors like this are scary. More so than, say,
explosives with the cap installed. At least the explosives can't
"reach out and grab you" or, more likely, make a giant bugzapper.
I was working on my system with the caps charged up to a few kJ, the
hiss of corona in the air, and a fly landed on one of the conductors,
and, it would appear, creating a field concentration of sufficient
magnitude to result in a breakdown. Loud noise, broken parts, smoke
in the air, and a thoroughly frightened experimenter. This is like
having someone fire a shotgun next to you without any warning
(including spraying shrapnel around).
Lessons learned: enclose the gear - leave LOTS of room between HV
parts and other things - make sure that if flashes over, it goes
somewhere *relatively* harmless - better to break parts than people.
Jim