Re: Ballasting the secondary side of transformers

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Gerry  Reynolds" <gerryreynolds@xxxxxxxxxxxxx>

Hi Bart,

Ballasting on either side should be equally effective at limiting the 
current.  Of course, on the HV side, the inductance value needs to be 
the turns_ratio (n) squared times larger because it has n times the 
voltage to deal with and needs to limit the current to 1/n times the 
current on the primary.  This assumes an ideal transformer between 
the LV and HV ballast points.

LV ballasting:      + smaller inductance needed, lower voltage stresses.
                          - larger current means larger guage.
                          - core is needed to get the inductance and 
saturation needs to be considered.

HV ballasting:      + smaller current.
                          - HV insulation needs to be considered.
                          - inductance needs to be n^2 larger.
                          - core is needed to get this larger 
inductance and saturation needs to be considered.

These are all of the plusses and minuses that I could think of.  If 
others, maybe someone else could chime in and comment on what is said.

Gerry R.


> Original poster: "Barton B. Anderson" <bartb@xxxxxxxxxxxxxxxx>
>
> Can someone please tell me why we are still ballasting on the LV 
> side of Pigs and PT's? This should be easy enough to do for a fixed 
> current limit. The costs associated with a LV ballast almost demands 
> we do this. The LV side is starting to appear very silly to me at 
> the moment. Granted, there are HV concerns, but is it really a big 
> deal? I get the feeling LV ballasting is simply convenient. However, 
> it is also expensive (unless one builds a ferrite ballast).
>
> Just curious is anyone else has contemplated a high side ballast.
>
> Take care,
> Bart
>
> Tesla list wrote: