Re: pig ballasting
I agree with scott that inductive ballasting is the way to do
it, with a little series R to calm down the inductors a bit. However the
way Scott suggested of doing the variable current limit is a bit inelegant.
The best way to do a simple variable current limit is to wind an inductor to
limit to the least power you think you're gonna need (maybe 5A for a 240V
pig system) with wire to cope with the most your gonna need (maybe 50A for a
240V pig system). Then slot the holes for bolts which hold on the I piece
of the EI core. Now all you have to do to change the current limit between
5 and 50 amps is to loosen the bolts and then move the I piece away from the
E then re-tighten the bolts, not forgetting to pack the core gap to stop it
> Original Poster: "Bunnykiller" <bigfoo39-at-idt-dot-net>
> Tesla List wrote:
> > Original Poster: CTCDW-at-aol-dot-com
> > Hello everyone,
> > I have now heard about resistive ballasting, inductive ballasting, and
> > at the same time.
> Hi Chris..
> I tried both resistive and inductive ballasting and found that inductive
> is the way to go reason why....
> resistive ballasting by itself ( i tried multiple hot water heater
> reduces the amount of voltage going to the pig as you use the resistors
> to limit the current lets say you want to supply the piggie with 15
> amps to do this you need a resistor of 16 ohms ((( 240V/15A =
> 16ohms)) but since the piggie has its own resistance it creates a
> voltage drop across the 16ohms... and the piggie sees less voltage
> inductive ballasting reduces the current but not the voltage ( not by
> much anyway)
> my present setup uses 3 EI cores wound with #10 TTHN solid core copper
> each EI core is modified a bit to produce a different current draw ...
> as you add each EI core into the system the current delivered by each EI
> core increases the current to the piggie there is one drawback to
> this system ... the inductors can cause a surging or bucking between the
> current limiting inductors and the piggie to solve this a low ohm
> resistor ( but hi power ability) is placed into the system to "balance "
> things out
> to find large EI cores look for burned out car battery chargers ( the
> roll around type), old welding machines, or the charging units for those
> huge computer back up systems check the local salvage yards also
> Scot D