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Re: Pig questions

Subject: 
        Re: Pig questions
  Date: 
        Fri, 4 Apr 1997 13:14:40 -0700 (MST)
  From: 
        Chip Atkinson <chip-at-xig-dot-com>
    To: 
        Tesla List <tesla-at-pupman-dot-com>


Greetings,

As a fellow pig handler, I thought I'd add my experiences.  

As has been stated, the arc welder is put in series with the pole pig.
This means that one side of the power line goes into the welder, then
out
of the welder, and finally into the pig.

The most important bit of experience that I have is when connecting the
variacs, welder, and pig all together.  I originally had the welder
between the pig and variac, but since I also had the center tap of the
pole pig connected to the house neutral (center tap of the neighborhood
supply transofrmer), the breakers would trip even when the variac was
turned down all the way.  Here's why:

1-------------- W -----------
       3\         CT  ______ 3
     V 3 \           /       3 PP
       3  \________ /________3
2------            /
------------------/

W -- Welder
V -- Variac
3 -- Windings of a transformer
PP -- Pole Pig
CT -- Center Tap (Neutral)

Note that the \'s which represent the movable part of the variac
effectively short out the ends of the pole pig.  The problem arises
when the current comes in on line 1, bypasses the welder W, and goes
between the CT and the hot line 1.

I am now rewiring my power cabinet to place the welder before the
variac on the common line of the variac.  This will allow me to
connect the center tap of the PP.  This is not electrically
important to my knowledge, but I just don't like the idea that I
can't connect a wire up that's not supposed to have any effect and
cause a short.  I also have to re-meter the thing anyway since my
voltmeter basically blew up, and my ammeter is not working
correctly, and I want to put in a variac for the rotary gap, and I
like tinkering with this stuff... whew.

Oh, BTW, I took the volt meter off the panel it was mounted to and
found that it had blown a pin hole through the 16ga steel that it
was mounted on.

Chip


On Sat, 29 Mar 1997, Tesla List wrote:

> Subject: 
>         Re: Pig questions
>   Date: 
>         Sat, 29 Mar 1997 12:19:13 -0500
>   From: 
>         "Lord Talimar" <lordtali-at-mill.tds-dot-net>
>     To: 
>         "Tesla List" <tesla-at-pupman-dot-com>
> 
> 
> how does one use an arc welder for a current limiter?
> 
> LT
> 
> 
> ----------