3-phase power; was: cctalk Digest, Vol 88, Issue 2

[Grant Taylor]

On 1/4/22 4:46 PM, Chuck Guzis via cctalk wrote:
> In fact, in my neighborhood, each house has a big green disconnect 
> box on the street fed by 3-phase 11KV.   Every so often, the utility 
> sends out a notice that they'll be "re-balancing" the distribution. 
> I imagine that that involves nothing more than changing one phase 
> wire in the big green box.

I'm used to 1-4 houses being on a common transformer where I grew up. 
They were usually installed on polls / pads at the corner of one of the 
properties on the back property line and feed the four touching properties.

> He advised that I should put some distance between the transformer 
> and myself, as it wasn't unusual for these things to turn into 
> pyrotechnic displays.

Ya.  I've seen some spectacular videos.  The higher the voltage, the 
more spectacular.

> When I worked in heavy industry, it was eye-opening to see the range 
> of voltages, phasings and *frequencies* entailed in the operation 
> (we had 25 Hz, 60 Hz and DC). And, of course, the mistakes made by 
> the electricians in installing various equipment.

I knew about 50 and 60 Hz and DC growing up.  I learned about 400 (?) Hz 
being used in military applications about a decade ago.  25 Hz was a 
surprise to me over the last year or so.  I read some interesting 
things, much of it related to Niagara Falls and other power systems 
modeled after it.

Voltages around the world through the last century was also interesting 
to read about.  As was single, two (90°), and three (120°) phases.



-- 
Grant. . . .
unix || die