Re: Single-bushing 14.7kV pigs. Thoughts?

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: Bart Anderson <classi6-at-classictesla-dot-com> 

Hi Aaron,

There's no downside if your just using one unit. The only thing different 
is with a double bushing unit, you have the ability to float the output. I 
have a double bushing unit, however, I connect one bushing to RF ground 
simply to prevent floating the outputs (I want the inner primary and bottom 
secondary at the same potential). I'm effectively turning my double bushing 
unit into a single bushing unit.

Take care,
Bart

Tesla list wrote:

>Original poster: "J. Aaron Holmes" <jaholmes-at-silicon-arcana-dot-com>
>After months of searching and drooling over
>hopelessly-expensive 5kVA units on eBay, I finally
>found a cheap local source for used pigs (in Seattle).
>  The price was $100 for a 14,760V 15kVA unit, the
>smallest unit they had.  I was so ecstatic, I bought
>two for twice the price :)  Never hurts to have a
>spare, after all.
>
>Trouble is, they're the single-bushing sort.
>
>Now, this may or may not be a big deal; I've been a
>long-time lurker on this list, but I've never gotten a
>good feeling for exactly what the downside is to
>having only a single HV bushing.  If I wire up the
>outer two bushings on the LV side and ground the case,
>can't I just treat the case like the other HV bushing?
>
>Sounds like most people with single-bushing units have
>the 7200V variety, so series-phasing them makes sense
>for several reasons.  I'm not sure what good it does
>me, though.
>
>If this has been dealt with a million times, feel free
>to scorch me.  I deserve it :)
>
>Regards,
>Aaron
>
>
>
>