Re: NST Shunt Removal (fwd)

["Tesla list" <tesla@xxxxxxxxxx>]

---------- Forwarded message ----------
Date: Tue, 12 Jun 2007 19:32:00 -0600 (MDT)
From: Chip Atkinson <chip@xxxxxxxxxx>
To: Tesla list <tesla@xxxxxxxxxx>
Subject: Re: NST Shunt Removal (fwd)

I made a box for the transformer of 1/2" thick plexiglas.  I glued the
whole thing together and it's not leaked so far (~8-9 years).  It depends
on how badly you want to avoid any leakage, but if you just have a snap on
lid like tupperware, you'll get seepage.

Chip

On Tue, 12 Jun 2007, Tesla list wrote:

> 
> ---------- Forwarded message ----------
> Date: Tue, 12 Jun 2007 19:20:27 -0400
> From: otmaskin5@xxxxxxx
> To: tesla@xxxxxxxxxx
> Subject: Re: NST Shunt Removal (fwd)
> 
> Thanks everybody for the advice.  Sounds like heat is the only potential problem - which I gather can be managed with oil emersion & possibly tempurature monitoring.  I don't usually do very long runs anyhow - maybe a minute or minute and a half.  
> 
> I'm going to find a suitable container for the depotted NST & then I'll have a good idea of how much transformer oil I would need.  I'll contact you, Dr R, to order some - thanks for your offer.  
> 
> What does everybody usually use to contain an oil-immersed NST?  Tupperware type of stuff?  I assume a container slightly bigger than the NST would contain enough oil for sufficient cooling.
> 
> Thx again, Dennis Hopkinton MA
> 
> 
> -----Original Message-----
> From: Tesla list <tesla@xxxxxxxxxx>
> To: tesla@xxxxxxxxxx
> Sent: Mon, 11 Jun 2007 6:30 pm
> Subject: Re: NST Shunt Removal (fwd)
> 
> 
> 
> 
> --------- Forwarded message ----------
> ate: Mon, 11 Jun 2007 18:01:45 -0500
> rom: resonance <resonance@xxxxxxxxxxxx>
> o: Tesla list <tesla@xxxxxxxxxx>
> ubject: Re: NST Shunt Removal (fwd)
> 
> You can safely remove the shunts for much more power, up to 80% more current 
> utput, if you drop the transformer into a tupperware or other suitable 
> lastic container with transformer oil.  No, the higher current is not a 
> roblem if the xmfr is protected in xmfr oil.  Heat is the enemy here.
> Always use a Terry filter and a safety spark gap to prevent spikes and 
> verpotentials.
> If anyone requires xmfr oil for a project we stock it in 55 gal. drums and 
> ould pump out a few gallons.
> Dr. Resonance
> This was brought up by another coiler in an earlier post, but I don't 
> elieve anyone answered it. Does removing shunts make an NST more 
> usceptible to failure, or is it a safe way to increase output? Thanks for 
> ny advice, Dennis Hopkinton MA
> 
> ----Original Message-----
> rom: Tesla list <tesla@xxxxxxxxxx>
> o: tesla@xxxxxxxxxx
> ent: Mon, 11 Jun 2007 9:24 am
> ubject: RE: NST Shunt Removal (fwd)
> 
> 
> -------- Forwarded message ----------
> te: Sun, 10 Jun 2007 18:33:34 -0700
> om: Jim Mora <jmora@xxxxxxxxxxx>
> : 'Tesla list' <tesla@xxxxxxxxxx>
> bject: RE: NST Shunt Removal (fwd)
> ello,
>  too modified a France 12/30 removing half the shunts and potting it a
> xture of melted Vaseline and paraffin. It arcs a Really hot flame!
> im Mora
> ----Original Message-----
> om: Tesla list [mailto:tesla@xxxxxxxxxx]
> nt: Sunday, June 10, 2007 3:51 PM
> : tesla@xxxxxxxxxx
> bject: NST Shunt Removal (fwd)
> --------- Forwarded message ----------
> te: Sun, 10 Jun 2007 16:05:07 -0700
> om: Barton B. Anderson <bartb@xxxxxxxxxxxxxxxx>
> : Tesla list <tesla@xxxxxxxxxx>
> bject: NST Shunt Removal
> i All,
> y 4.5" diameter coil spark lengths are far beyond a 12/60 NST capability.
> tp://www.classictesla.com/photos/ba45/ba45.html
> d these pics don't really show the lengths I've seen with this coil.
> he NST I use was modified by fixing some hv windings and removing 1/2
>  the shunts (back when I documented the NST depotting procedure. So,
> e 12/60 Franceformer is no longer a 12/60. At the time, I never
> nished the measurements on the NST. Well, I rebuilt my hv divider
> day using 6 100Meg HV resistors (mfg p/n EX2G1006, $1.66ea). These are
> de by Ohmite and good for 7.5KV each (I have 3 in series on each leg
> r 22.5KV at 300Meg). Anyway, following calibration, I tested an
> modified 15/30 Franceformer. All came out as it should. Here's the
> ta for the unmodified 15/30 NST.
> =0.8 ohms, Rs=16230 ohms.
> PEN CIRCUIT MEASUREMENTS:
> pri = 124.1 V
> pri = 0.74 A
> pri = 24 W
> _pri = 91 VA
>  = 0.27
> sec = 15340 V
> HORT CIRCUIT MEASUREMENTS:
> pri = 124.0 V
> pri = 3.83 A
> pri = 39 W
> _pri = 474 VA
>  = 0.08
> sec = 25.74 mA
> nowing that the hv divider is working well, I decided to unbolt the
> dified 12/60 and run it through both open and short circuit
> asurements. Here is what I found: btw, Rp=0.45 ohms, Rs=4660 ohms.
> PEN CIRCUIT MEASUREMENTS:
> pri = 124.2 V
> pri = 1.53 A
> pri = 50 W
> _pri = 190 VA
>  = 0.26
> sec = 13380 V
> HORT CIRCUIT MEASUREMENTS:
> pri = 121.3 V
> pri = 20.3 A
> pri = 428 W
> _pri = 2457 VA
>  = 0.18
> sec = 206.7 mA
> o, as you can see, this NST is no longer a 12/60, closer to a 13/200
> d that explains the arc lengths being so good, or really, "not that
> od" considering I am about 20" shorter than I should be for this power.
> r. Resonance was wondering why the little coil was doing so well and
> d asked me offline. I let him know the NST was modified, but I didn't
> ve the data to give him at the time. I've probably pushed that NST to
> e brink of saturation, but, it has held up well, it just keeps on
> nning. It's reliability is a pleasant surprise considering what I know
> ow" about the modifications.
>  took out exactly 1/2 the shunts. I_sec jumped from 60mA to 200mA (more
> rrent than I intended). I was hoping removing 1/2 the shunts would be
> linear jump to 120mA, but that was just a shot in the dark. If I were
>  modify an NST again by removing shunts, I would only remove 1/4 of
> e shunts. 1/2 seems a bit much. This NST is more like a PT or
> mbarder now. I really don't know how long it will last. Last week, I
> st an XBOX 360 and my main computer (video section on motherboard
> mmitted suicide). This was due to a small 2" coil that I ran without
>  RF ground. Big mistake. However, my NST Terry Filter smoked with this
> 5" coil Thursday. The coil and NST still run great, but the Terry
> lter has some burnt resistors. Looks like I'll have to check all those
> V's!
> ust thought this data might be of interest to anyone considering shunt
> difications. I know those that happen to manage NST shunt removal like
> e fact they have (more power, baby!), but not everyone makes the
> asurements following the modification. And considering what I found,
> 2 the shunts removed might be stretching (or not depending on your
> ew of things).
> ake care,
> rt
> 
> 
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