PT's, care and feeding

["sundog" <sundog-at-timeship-dot-net> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)]

Hi all.  I'm going to call on those PT's tomorrow (monday), and
hopefully get a definate price on 'em, plus more details.  The
things I'm after finding out from the list...


TRANSFORMER, POTENTIAL, 60 HZ, TYPE PT,
25 PRIMARY 24,000/24,000Y, RATIO 200:1,
INSULATION RATED 25 KV 60 HZ, 150 KV
THERMAL RAT. 30C, IL-44-060-2, LINE 1

what the heck does the 24000/24000Y mean?
25 primary....uh...I'm drawing a blank..25 primary turns?
the 200:1 ratio I get..feed it 120v, you get 24kv...Great for TC
use :)  Good high voltage (33kv peak to peak!)
insulation rated 25kv, 60hz, 150kv...Figure the max sustained HV
output should be 25kv (means the skimped on the HV insulation),
150kv spike...Am I right?  24kv is the most voltage I want out of
it, but I intend to push it beyond the faceplate rating by
1.5-2-3x.  At least for the 10 second runs ;) As an afterthought,
could it digest 240v, low amperage, or would the HV windings be at
risk of breaking down due to corona?

Thermal rating, 30C   A 30C increase from ambient temperature, I
assume.  Means I can run this jewel near 180-200 core temp before
it "melts down", again, I assume. I don't know if these are oil
filled or potted.  I assume an oil filled will recover from thermal
heating faster than a potted tranny, because electrical insulation
happens to usually be great thermal insulation...hmm..maybe a meat
thermometer in there with it?  When the button pops up, better take
a bar-b-q break and let the tranny cool?

Things I am curious about, before I buy these/build the MMC when/if
I get 'em.

   The Panasonic MMC's can handle a decent amount of RMS amperage.
I'm not worried about the current much, as cap warming on a short
run is a good indication of pushing the limits, plus Terry's
MMCCalc tells you what temp change you can expect.  Beautiful work.
What I wonder....
  If I'm ballasting this with inductive ballast, chances are I'll
get "inductive kick" going into it.  Does inductive kick increase
just the current, or the voltage as well?  I can deal with 50-100
extra mA, but if it increases the voltage, there's a problem.  I'd
have to figure the max voltage the inductive kick would put into
the tranny, and build the caps accordingly, as they're already run
way beyond their rating for this useage.  At 200:1 ratio, it's even
more important, 'cause a 100v spike means a 2kv spike on the
caps...some vague importance like "overvoltage" comes to mind.....
  Could a guru or two (or more, or non-guru) please shed some light
on this for me?    As it is, I'm planning on using a MOT for
ballast, and running as much PFC as I can to get what I need.  I
feel I should be prepared and know what I'm dealing with before I
drag these home to take up space in an already crowded garage

  I'm taking my meter with me if/when I go to get them (though I'll
already own them by then), to check a few things.  what I want...
(primary=120v side)
   low resistance between the primary leads
   low resistance between the secondary leads
   high resistance between either primary and secondary leads
   ideally, high resistance between secondary leads and case, but
can live with low resistance)
    high resistance between primary leads and case.

  That'll mean the primary is isolated from the case (and most
likely secondary), and even if the secondary is grounded to the
case, it's not much hassle to ground the case to the RF ground to
prevent it from floating up to some high voltage and zapping
whatever fool gets too close.  Is hooking the tranny to the RF
ground a Bad Thing(tm)?  I figure if I'm getting RF kickback on the
tranny feeds to the tank circuit, then the ground would carry those
RF spikes away, so the house ground is not a good place for them.
For the control panel, yes, but not the tranny.  Right? Wrong?
Indifferent?


Thanks for your time, and for reading this long post :)  With the
help from the list, I've gone from ignorant simpleton to ignorant
simpleton with an idea and a spark to learn (no pun intended).  I
love these things, and despite neighbors and lack of time, enjoy
watchin' the sparks fly as the sun sets.  I love the smell of ozone
in the evening ;)
                                                            Caio!
                                                              Shad