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Re: Capacitor Safety Discharge Method (fwd)



---------- Forwarded message ----------
Date: Tue, 07 Aug 2007 00:20:49 -0400
From: Crispy <crispy@xxxxxxxxxxx>
To: Tesla list <tesla@xxxxxxxxxx>
Subject: Re: Capacitor Safety Discharge Method (fwd)

>From what I've seen, high voltage relays can be pretty expensive.  I
think a much cheaper way to construct a device like that would be to use
pull-style linear solenoids, such as McMaster-Carr #70155K48 .  However,
a single one of these solenoids would not be suitable if the max voltage
across the capacitors would be able to jump a 7/8" gap.  Two solenoids
opposing each other would double the distance.  I'm about to construct a
test device with two solenoids to do this.  I'll use that above
solenoids from MCMaster-Carr, with round-headed screws for electrodes,
and several inches of HDPE for insulation between the solenoid and high
voltage.

On Mon, 2007-08-06 at 20:54 -0600, Tesla list wrote:
> ---------- Forwarded message ----------
> Date: Mon, 06 Aug 2007 20:38:11 +0000
> From: nancylavoie@xxxxxxxxxxx
> To: Tesla list <tesla@xxxxxxxxxx>
> Subject: Re: Capacitor Safety Discharge Method (fwd)
> 
> Hi, Chris. Thats exactly what I was trying to get an answer to in the
> previous posts and I think that if you kind of read between the lines in
> Bart's reply, you can see that its probably okay to do if you use bleeder
> resistors and discharge the cap after the charge has bled off. What I
> wanted to use was a Ross Engineering relay rated at 40 kv (normally open
> contacts) and wire it across the terminals of the capacitor and
> resistors.It would then just be a simple matter of flipping a switch and
> doing the work of the screwdriver in a much safer fashion.Anyone see a
> problem? Wyatt
> 
> -------------- Original message -------------- 
> From: "Tesla list" <tesla@xxxxxxxxxx> 
> 
> > 
> > ---------- Forwarded message ---------- 
> > Date: Mon, 06 Aug 2007 01:53:57 -0400 
> > From: Crispy 
> > To: tesla@xxxxxxxxxx 
> > Subject: Capacitor Safety Discharge Method 
> > 
> > Hello, 
> > 
> > In light of the recent discussion about the necessity of a manual 
> > discharge for the tank capacitor in addition to bleeder resistors, I've 
> > been considering an easier method of manual discharge than the 
> > stick-a-screwdriver-in-the-spark-gap method for my coil. I was thinking 
> > about an electronic method, and here's the idea. Would it be possible 
> > to have a linear pull-style solenoid with an electrode that, when 
> > powered, would retract its electrode from another static electrode, to 
> > act as the safety discharge? The normal state (no electricity applied) 
> > would be to have the contacts together, and the capacitor shorted. Of 
> > course, the electrodes would have to be insulated from the solenoid. 
> > Also, would it be possible to immerse this under oil, if the gap 
> > provided by the solenoid was insufficient to prevent sparking over in 
> > normal operation, or would the oil coat the electrodes and somehow 
> > prevent safety discharge? 
> > 
> > Thanks, 
> > Chris 
> > 
> > 
> > 
> 
>