Re: The Geek Group High Voltage Capacitors, making a HV switch, (fwd)

["High Voltage list" <hvlist@xxxxxxxxxx>]

Original poster: Steven Roys <sroys@xxxxxxxxxx>



---------- Forwarded message ----------
Date: Sun, 12 Nov 2006 09:03:41 -0600
From: Bert Hickman <bert.hickman@xxxxxxxxxx>
To: High Voltage list <hvlist@xxxxxxxxxx>
Subject: Re: The Geek Group High Voltage Capacitors, making a HV   switch,
      (fwd)

High Voltage list wrote:
> Original poster: Steven Roys <sroys@xxxxxxxxxx>
> 
> 
> 
> ---------- Forwarded message ----------
> Date: Thu, 9 Nov 2006 17:37:34 -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)
> 
> Hello All,
> 
> Taken under advisement so far: use virgin UHDP 1.5" solid rod, 4' long to
> throw the charge, open and discharge connections. Opposite charges shall not
> be closer than 4" or more as possible. 1.5" to 2" copper pipe to join the
> center lugs of the capacitors and to provide a return connection. 

You can use smaller (1" diameter) copper pipe for easier construction, 
lower cost, and sufficient corona suppression at ~40 kV. Aluminum 
conductors can also be used, but you'll need to do some joint 
preparation beforehand to insure joints capable of handling 100+ kA 
currents. Carefully sand or brush the areas to be joined, and 
immediately apply an antioxidant joint compound (such as Burndy Penetrox 
A or A13 or Harger NO-OX-ID or HAAJC1/2). This should result in minimal 
buildup of aluminum oxide on mating surfaces prior to joining. Conical 
(Belleville) washers are also suggested to prevent loosening over time, 
since aluminum may cold flow under compression.

> Sleeping
> on method of grounding capacitors together, perhaps 2 2" copper pipes
> flattened a mated with as many as possible attachment screws or 2 2" buss
> bars. SPDT to be mounted on 5" ceramic standoffs attached to 5/8 G10 10X12
> base material. Discharge to be done by a series of 10" long ceramic 1.125"
> diameter Ceramic HV resistors capable of a complete discharge from 40KV.
> Activation via a 4" pneumatic plunger connection to 2" brass dowels.
> Remotely controlled from a 10' * xKJ Tygon tubing.
> 
> Many Thanks,
> 
> Jim Mora   
> 
> -----Original Message-----
> From: High Voltage list [mailto:hvlist@xxxxxxxxxx] 
> Sent: Thursday, November 09, 2006 1:56 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: Wed, 08 Nov 2006 05:53:24 -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)
> 
> At 04:46 AM 11/8/2006, High Voltage list wrote:
> 
>>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.
> 
> 
> 40 kV/inch is pretty bold.  Breakdown in a uniform field is 70 
> kV/inch, and anything with curved components is hardly uniform.  Your 
> 40 kV/inch has a safety factor of less than 2.
> 
> One rule of thumb might be an inch per 10 kV.  Watch the radius of 
> curvature for corona losses.  At 20 kV, the *radius* needs to be on 
> the order of 1/4"..  1/2" diameter
> 
> Air insulated HV stuff tends to be quite bulky.
>