Re: Cat's meow and 3-phase question was: Silly question?

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Original poster: "Malcolm Watts by way of Terry Fritz <twftesla-at-qwest-dot-net>" <m.j.watts-at-massey.ac.nz>

Hi David,

On 27 Sep 2001, at 20:26, Tesla list wrote:

<snip>
> Now, I have a question about utility three phase transformer 
> service that is bothering me and I was hoping some of the re- 
> sident engineers could answer it  for me. I've read that a wye/ 
> wye three phase transformer hookup is rarely used by the 
> utility power companies because of harmonics and balancing 
> problems. However, virtually all of the three phase pole pig 
> banks that I see in my local area (Memphis, TN) are hooked 
> up exactly this way (all three phases sharing a common 
> ground return on both the primary and secondary sides of the 
> transformer). I was wondering if anyone could shead light on 
> this for me? 

I can only guess from experience with the local supply here in NZ. 
The basic idea is to hive alternate phases to alternate houses to 
implement a crude form of load balancing with a neutral return.

Regards,
Malcolm