Re: Pole Pig Simulation

[Tesla729-at-cs-dot-com (by way of Terry Fritz <twftesla-at-uswest-dot-net>)]

In a message dated 9/6/00 7:16:31 PM Pacific Daylight Time, tesla-at-pupman-dot-com 
writes:

<< 
 Again, a ballast really makes a mess of this. As L-Ballast is increased,
 the phase angle increases and it also limits current (therefore, any
 current or voltage reading past the ballast cannot be used for identifying
 a PF based on Volt-Amps or Watts). If the method decribed above will
 perform the same function, then I've got some interesting info about
 ballast PF correction, but if not I could sure use some ideas.  >>


Hi Bart, all,

All of the complex mathematics of these PFC calcs really gets over
my head, but I will say that w/ my "medusa" system, I use a 10 KVA,
14.4 KV pig fed by up to 280 volts from my variac and ballasted by a
Lincoln 225 amp arc welder in series w/ the pig's LV inputs. Of couse 
the welder's output leads are kept shorted and I usually keep the wel-
der's amperage selector on 175 or 200 (225 is the max). Having said
all of this, when the variac is turned all the way up, my pig only draws
~ 45 amps -at- about 250 volts, according to my panel meters. Of course,
the coil is spewing out almost constant white hot arcs to the walls and 
the floor in my little 12x20 ft shop -at- this level, so I don't ever run it for
more than a few seconds at a time this level, as it may start a fire! I'm
not sure how I would actually determine the "true" wattage drawn at 
this level, but it seems to me that there is not much of a power factor
problem at all as I'm only drawing around 11 KVA from the pig -at- max
power, according to my panel meters. I can see where the extra L added
by the ballast would cause a real nightmare in calcing the PFCs for a pig
or PT setup, though. As I stated earlier to this list, it seems that most
pig coilers don't worry too much about PFC anyway, since there is ob-
viously plenty of power to spare from even a 5KVA pole pig, and since 
a system this large will usually have a dedicated 240 volt/50 amp circuit. 
It seems to me that 45 amps max is not a bad current draw for a system 
of this magnitude, though IMHO.

My $.02,
David R.

ps-- I suppose the load of the pig drops the input voltage to the 250-255
volt range from the variac -at- max position although the open circuit volt-
age would be 280 volts.