Re: Capacitor Safety Discharge Method (fwd)

["Tesla list" <tesla@xxxxxxxxxx>]

---------- Forwarded message ----------
Date: Wed, 08 Aug 2007 01:43:57 -0400
From: Crispy <crispy@xxxxxxxxxxx>
To: Tesla list <tesla@xxxxxxxxxx>
Subject: Re: Capacitor Safety Discharge Method (fwd)

On a DC coil, is it safe to use a wirewound resistor in this way to
discharge an electrolytic smoothing capacitor?  Would the inductance in
the resistor set up a high-frequency oscillation which could harm the
caps due to voltage reversals?

Chris

On Tue, 2007-08-07 at 06:45 -0600, Tesla list wrote:
> ---------- Forwarded message ----------
> Date: Mon, 6 Aug 2007 23:34:56 -0500
> From: resonance <resonance@xxxxxxxxxxxx>
> To: Tesla list <tesla@xxxxxxxxxx>
> Subject: Re: Capacitor Safety Discharge Method (fwd)
> 
> 
> One can make up an inexpensive HV relay using a standard 120 vac  1" 
> solenoid.  Just mount a pair of tungsten contacts.  Use a small "leverage 
> arm" so that the solenoid moves the contacts approx 3 inches and discharge 
> thru a high power 5 Ohm wirewound resistor.  Works great and fab cost is 
> around $25.
> 
> As someone else commented, always check with a hotstick in case the resistor 
> ever blows out.  NE-2 neon bulb connected thru a 1 meg resistor in series 
> (to ground)  attached to a plastic rod works good to detect any remaining HV 
> charge.
> 
> 
> Dr. Resonance
> 
> Resonance Research Corp.
> www.resonanceresearch.com
> 
> 
> ----- Original Message ----- 
> From: "Tesla list" <tesla@xxxxxxxxxx>
> To: <tesla@xxxxxxxxxx>
> Sent: Monday, August 06, 2007 9:54 PM
> Subject: Re: Capacitor Safety Discharge Method (fwd)
> 
> 
> >
> > ---------- 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
> >>
> >>
> >>
> >
> >
> > 
> 
> 
> 
>