On Tue, 19 Jul 2016, Paul Koning wrote:
Anything powered by electric motor above 2 hp or so often comes in 3
phase, and when you get to somewhat higher power (5 hp or so) it seems
to be about the only option. Lathes and milling machines are good
examples.
and air compressors in automotive shops, maintaining a large tank of
compressed air.
3-phase comes in "delta" or "Wye"("Y")
some installers don't know the difference!
I experienced TWO misdone installations. One was an auto garage, and
resulted in high voltage to the 110 outlets, damaging a bunch of minor
stuff, such as grinder, space heater, clock, etc.
The other was was a PDP installation. After excessive downtime of third
party disk drive, the community college had sold it to a neighboring
school district, and bought a roomful of PCs. Microsoft PC COBOL and
Fortran were crap, but quite adequate for teaching the languages, and it
was great to have dozens of machines for students to use without fear of
downtime. PG&E (our power company) agreed to buy a new replacement
computer, if those involved would go along with the fiction that it had
been a lightning strike (NOT common here). The bad drive ceased
to be a problem. Everybody was happy, and PG&E got to call it a donation
on their taxes.
