Re: NST Shunt Removal (fwd)

["Tesla list" <tesla@xxxxxxxxxx>]

---------- Forwarded message ----------
Date: Tue, 12 Jun 2007 18:30:04 -0700
From: Barton B. Anderson <bartb@xxxxxxxxxxxxxxxx>
To: Tesla list <tesla@xxxxxxxxxx>
Subject: Re: NST Shunt Removal (fwd)

Hi Dennis,

For an NST, I just use the NST case. But for MOT's, I used an Army 
ammunition can which I got the idea from someone here on the list (I 
think Gary did this). The can was perfect for the task. I just happened 
to be driving over the pass to Nevada, stopped at a gas station, and 
there was a garage sale of sorts right there at the gas station (weird). 
But, they had two Army green ammo cans and I bought for like a dollar 
each. Totally sealed and the lid has an excellent seal strip. It also 
includes a carrying handle on top to make it that much nicer. You have 
to drill some holes in the top or top of sides for bushings, but other 
than that, it's a perfect canister for these little tranny's.

Take care,
Bart

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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