Re: Inductive Kick LTR Pig Systems

[Terry Fritz <twftesla-at-uswest-dot-net>]

Hi Robin,

	It seems like your system should pull about 55 amps RMS from a quick
model.  Looks like the firing voltage is around 28kV.  So:

1/2 x 60nF x 28000^2 x 200 = 4.7kW

You are putting in 240 x 55 = 13.2 kW

So the power factor seems pretty bad.  Realize that I am just typing
numbers into a keyboard and guessing here but...

A 500uF cap could probably knock 20 amps off the current for 8.4 kVA.  That
would allow your variacs and all to run better.  Since you are firing at 4
times the line frequency and seem to have a fair amount of ballast to limit
the voltage on the caps, things do not seem "optimal" here on the other
side of the world ;-))  but I would try the PFC caps with care as a start.

Note that this is all arm waving so take it with a grain of salt, buyer
beware and all...

Do you have a web page that describes you system?  If you could measure the
DC resistance of your pig's secondary too, it would fill in a hole in the
model...

Cheers,

	Terry


At 08:52 AM 8/27/00 +0930, you wrote:
>Hi Terry, all:
>
>
>Tesla list wrote:
>
>> Original poster: Terry Fritz <twftesla-at-uswest-dot-net>
>>
>> Hi All,
>>
>>         I was plugging away at a few Inductive Kick Larger Than Resonant 
>designs
>> with pig transformers with MicroSim.  I can fairly easily charge a 270nF
>> cap to 20.3kV at 120BPS while staying inside the "specs" of everything.
>> However, that is only:
>>
>> 1/2 x 270x10^-9 x 20300^2 x 120 = 6676 watts
>>
>> for 10kVA input.  The problem is the power factor is really bad!  Do people
>> use PFC caps with pig systems??  I assume the "limit" of such a system is
>> the AC line current available.  PFC caps may do wonders for getting more
>> bang for the same current.  PFC cap could easily pull that power factor
>> right in.
>
>This is exactly where I am at the moment, my transformer is a 33kv/15KVA 
>rated unit
>(AUS 240V/50Hz in), I have 3 legs available each sub-board rated at 100 amps 
>but can
>go to 300 amps on the main board. The system specs at the moment are 200bps 
>sync
>rotary, 0.06uf mmc, variac current limiting.  At 100 amps from supply I am 
>still
>only charging the cap to 60-70% of full capacity. I am going to  introduce a 
>PFC cap
>into the system to improve the charging capacity on the supply side. Your 
>discussion
>about inductive kick on pig systems has piqued my interest. Any suggestions?
>
>Best Regards
>
> Robin Copini.
>
>
>
>
>>
>>
>> IK LTR Pig Systems (IKLTRPS) seem very interesting since we can change the
>> ballasting and get over a rather obnoxious tuning parameter that cannot be
>> adjusted on NST systems...
>