Re: VERY HIGH BPS at 6kw! 240 V into the 120 V

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Bert Hickman by way of Terry Fritz <teslalist-at-qwest-dot-net>" <bert.hickman-at-aquila-dot-net>

Terry,

Yes, this has been tried before. How high you can go before you encounter 
core saturation is a function of how much design margin your transformer has.

Leave the HV side disconnected and begin increasing the applied voltage 
while monitoring LV side current. At some voltage the LV side current will 
begin to substantially increase, and this may also be accompanied by a loud 
humming or growling noise. You'll likely hit this point somewhere  around 
150-165 volts. This is the onset of saturation, and attempting to increase 
the voltage much further will result mostly in heating the LV winding.

Remember that for an equivalent power at half the supply voltage, your 
primary current will be twice as high. Worse, if you use the same size tank 
capacitor and you are able to double the output voltage, you'd need 4X the 
primary current. The combination of these effects can cause much higher LV 
current draw when operated in this mode...

Best regards,

-- Bert --
-- 
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Tesla list wrote:
>Original poster: "Terry Blake by way of Terry Fritz <teslalist-at-qwest-dot-net>" 
><tb3-at-att-dot-net>
>Hey,
>Has anyone else pumped 240 V into the 120 V winding of a pole transformer?
>I was thinking about doing just that, but with a 14.4KV transformer.  Like
>pump in 240 V into the 120 V to get 28.8 KV out.  Hehe.
>Terry Blake
>----- Original Message -----
>From: "Tesla list" <tesla-at-pupman-dot-com>
>To: <tesla-at-pupman-dot-com>
>Sent: Wednesday, May 14, 2003 12:32 PM
>Subject: Re: VERY HIGH BPS at 6kw!
>
>  > Original poster: "G by way of Terry Fritz <teslalist-at-qwest-dot-net>"
><bog-at-cinci.rr-dot-com>
>  >
>  >
>  > >10' on 7200vac? That's very interesting. Can I trouble
>  > >you to describe your coil system--primary/secondary
>  > >dimensions & so forth, or else provide a link to a
>  > >description? I have a special interest in low-voltage,
>  > >high-current systems.
>  >
>  > snip
>  >
>  > >hi,
>  > >     id have to challenge this claim of spark length with a cap that
>small at
>  > >7200v
>  > >as the tank cap at low voltages tends to be big to make use of the large
>  > >current.
>  > >do you have any pics of this?
>  > >i dont usually question anyone on there output but this seems houge for
>the
>  > >size of tank cap
>  > >id love it if it were true then we could all learn something from you!
>  > >cheers
>  > >colin
>  >
>  > Hello All,
>  >
>  > I may have accidentally started some trouble with my statement about low
>  > voltage. I forgot that I was overdriving my transformer. I just ran the
>240
>  > V mains supply into one side of the low-voltage winding. Sure, it
>saturates
>  > and makes all the lights flicker, but it got the length up! I think I was
>  > making about 6 feet or so before I decided to overdrive it. The last time
>I
>  > ran the coil, I ballasted it at about 35 A, and got the 10 foot streamers
>I
>  > mentioned. Here is a list of specs from an old List email:
>  >
>  >
>  > power supply: 7.2 kV 10 kVA pole transformer, 240 V 60 A circuit,
>contactor
>  > actuated
>  >
>  > ballast: MOT tansformer array
>  >
>  > primary: 21 turns 1/4" copper (designed for experimentation), 1/4"
>spacing,
>  > tapped at 11 (10 to 12 seem to have exactly the same performance)
>  >
>  > cap: Geek  MMC, 0.041 uf 20 kV, 3 strings of 11
>  >
>  > gap: variac controlled right angle grinder ASRG, 11000 rpm,  5 tungsten
>  > flying electrodes, 1 or 2 gaps for BPS selection, plywood disk
>  >
>  > secondary: 8.5" dwv pvc pipe, 19.5 gauge wire, 1400 turns, 50" winding
>length
>  >
>  > topload: 3" corrugated black drain pipe/Aluminum tape corona shield,
>  > one  4" x 25"  and one 7" x 60"corrugated pipe/tape toroid
>  >
>  > extras: strike ring with inline 2" spark gap, 40 A emi filter
>  >
>  >
>  > Gregory
>  > --
>  > "Without ZIM, I am lost."
>  > GeekID#-1229
>  > http://thegeekgroup-dot-org
>  >
>  >
>  >
>  >
>
>.