Re: Ballasting a Pole Pig (Revisited)

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: Yurtle Turtle <yurtle_t@xxxxxxxxx>

FWIW,

I got 42.4 ohms on the HV side and .1 ohms on the LV
side. Mine's a 240/14.4 kV 25 kVA pig with aluminum
windings.

Adam

--- Tesla list <tesla@xxxxxxxxxx> wrote:

> Original poster: "J. Aaron Holmes"
> <jaholmes@xxxxxxxxxxxxxxxxxx>
>
> If you haven't already done so, you might try simply
> measuring the resistance of the pig windings, both
> the
> HV and LV.  Off hand, I can't think of what
> resistances would be "normal" for a pig the size of
> yours, and it probably varies quite a bit, even for
> pigs of the same rating.  Still, you should
> definitely
> *not* see a dead short or and open circuit on the HV
> side.  LV side may appear very close to a dead
> short,
> even if it is fine, however if you have a very
> accurate DMM then you may be able to measure the two
> 120V windings in turn (they should be the same) and
> then observe that the 240V lugs present double the
> resistance of the 120V lugs.
>
> Have you popped the lid on the pig to see if there
> are
> any signs of internal arcing?  Murky oil would
> definitely be a bad sign.  If, with the HV side
> unconnected, you cannot supply power to the LV side
> without tripping a breaker (even with no ballast)
> then
> something is definitely wrong.
>
> Another thing to be mindful of with pigs is that
> sometimes one of the LV lugs is not connected to
> anything inside the can.  This would be the case if
> the pig was used as part of a three-pack of
> transformers used to supply 208V three-phase power.
> In such an application, the two 120V windings are
> configured in parallel rather than series.  A look
> inside the can should make it obvious if this is the
> case.  If it is, then you may inadvertently be
> putting
> 240V into what should be a 120V winding, or you may
> effectively have one lead connected to nothing
> (though
> the latter would certainly not explain the breaker
> blowing!).
>
> aaron
>
> --- Tesla list <tesla@xxxxxxxxxx> wrote:
>
>  > Original poster: "C. Sibley" <a37chevy@xxxxxxxxx>
>  >
>  > I am unable to get any arc from the pig, at any
>  > power
>  > setting...
>  >
>  >
>  > --- Tesla list <tesla@xxxxxxxxxx> wrote:
>  >
>  >  > Original poster: "Gerry  Reynolds"
>  >  > <gerryreynolds@xxxxxxxxxxxxx>
>  >  >
>  >  > Hi Curt,
>  >  >
>  >  > Is the low voltage at the input of the pig
> with
>  > the
>  >  > JL arcing??  If
>  >  > so, the pig output is essentially shorted and
>  > will
>  >  > reflect to the
>  >  > input as a near short.   Open the JL so no
> arcing
>  >  > (no load on the PIG
>  >  > output) and see if the input voltage is at the
>  >  > variac output.    You
>  >  > can also remove the pig and drive just the
> welder
>  >  > with the variac and
>  >  > measure its primary current with various
> output
>  >  > current settings.  I
>  >  > bet with the welder set to max current, it
> will
>  >  > easily trip a 15A
>  >  > circuit breaker.  My welder draws 30 amps at
> its
>  > max
>  >  > setting (iirc)
>  >  >
>  >  > Gerry R.
>  >  >
>  >  > >Original poster: "C. Sibley"
>  > <a37chevy@xxxxxxxxx>
>  >  > >
>  >  > >David,
>  >  > >
>  >  > >I only have a 15A 220V circuit to play with,
> and
>  > am
>  >  > in
>  >  > >the process of getting the electrical
> upgraded.
>  > I
>  >  > can
>  >  > >run the setup for longer periods with the
> welder
>  >  > set
>  >  > >to a lower current.  But at the lower
> currents
>  > the
>  >  > >voltage to the pig is essentially zero.  I
> have
>  >  > >verified and cleaned all of the hookups.
>  >  > >
>  >  > >I'll try one of the other ballast methods and
>  > let
>  >  > the
>  >  > >list know what I find.
>  >  > >
>  >  > >Curt.
>  >  >
>  >  >
>  >  >