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WIRE and TRANSFORMER

 * Original msg to: Nussbaum-at-silly-dot-com
 * Carbons sent to: usa-tesla-at-usa-dot-net

Quoting Ephraim Nussbaum <nussbaum-at-silly-dot-com>:

> I'm unpotting a neon transformer the way you described. I have
> basically all the tar off except for some dirt that I didn't 
> clean off yet. I have a few questions. 1) what are the shunts 
> and what are they made of? 2) Is the core the heavy metal band
> that surrounds the windings? 

I am going to use your ASCII art as a start for the following
series of diagrams. The simplest, bare (no windings) core is
depicted below. It is made of stamped sections of flat iron 
sheet that are coated with a thin layer of enamel. This laminated
core is made to come apart, which is how the pre-wound primary
and secondary windings are fitted on to it. Usually where will be
a couple of long screws w/nuts or a couple of rivets that may be
drilled out to separate the iron core into two open sections. The
diagram below shows an assembled neon core in it's simplest form.

      _____________________________________________
     |                                             |
     |                                             |
     |     -----------------------------------     | 
     |     |                                 |     |
     |     |     OPEN RECTANGLE IN CORE      |     |
     |     |                                 |     |
     |     -----------------------------------     |
     |            STAMPED IRON SHEET               |
     |_____________________________________________|


The diagram below shows the simplest core above, but with 
the addition of the primary and secondary windings. The
primary winding is in the center, the two secondary windings
are towards the outside. There are two wires leading from the
120 volt primary winding, and one wire each from the outer layer
of the high voltage secondary windings. This gives a total of
four lead wires exiting the transformer. The base wires of the
two secondary windings are grounded to the core laminate.


                        120 VOLTS
          high voltage    v   v     high voltage
             __I__        I   I        __I__
            |  S  |     __I___I__     |  S  |
            |  E  |    |    P    |    |  E  |
     _______|  C  |____|    R    |____|  C  |______
     |      |  O  |    |    I    |    |  O  |      |
     |      |  N  |    |    M    |    |  N  |      |
     |     -|  D  |----|    A    |----|  D  |-     | 
     |     ||  A  |    |    R    |    |  A  ||     |
     |     ||  R  |    |    Y    |    |  R  ||     |
     |     ||__Y__|     ---------     |__Y__||     |
     |     -----------------------------------     |
     |                     CORE                    |
     |_____________________________________________|


Now, in order to limit the amount of energy, in the form of
magnetic field flux, that is exchanged between the primary 
winding and the two secondary windings: magnetic leakage shunts
are placed in the core on either side of the primary winding.
These shunts are nothing more than small blocks of the same
core laminate that makes up the rest core. The diagram below
shows the simplest neon core from the first diagram, without
windings, but now showing the correct placement for the mag-
netic leakage shunts:


      _____________________________________________
     |                                             |
     |                                             |
     |     -----------------------------------     | 
     |     |     |  |               |  |     |     |
     |     |     |  |  < SHUNTS >   |  |     |     |
     |     |     |  |               |  |     |     |
     |     -----------------------------------     |
     |                                             |
     |_____________________________________________|


> 3) You say to take softened polethylene sheet and press it  
> against the core and then take the windings and press them down
> on it. How would the windings pressed down on the sheet when 
> the core is around the windings?

The windings are around the core. When the two pinch bolts (or
rivets) holding the core together are removed, the core may be
disassembled into two sections. Once the core is apart, the 
windings may be slipped on and off. To prevent vibration, the
windings are usually wedged into place. Before reassembly of the
core it may be warmed; polyethylene carefully wrapped around the
laminate; and the windings gently but firmly pressed into place.


 > For a four inch coil what awg should I use.

24 AWG is the smallest wire I would use, 22 AWG works pretty
well.

Richard Quick 


... If all else fails... Throw another megavolt across it!
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