Thank you for the lessons in electricity! I take it I should be installing
"4-wire" outlets if I'm
planning to purchase new 220v tools from Delta or Grizzly, correct?

I've done a bit of reading, so I'm not as naive as I was a week ago, but I
was surprised to learn:

"240V is generated by tapping from a transformer at such points that one
leg is 180-deg out of phase (in time) w/ the other so when one leg is at
the positive sine peak the other is at it's negative max. The RMS
difference between these is then the 240V your voltmeter sees while each
(being AC) measures 120V to a neutral.

I have also learned about 3-phase power and the correspondance to induction
motors so this makes sense to
me in that context--expecially in that the hot lines to coils in the motor
will be hooked up in parallel rather than in series as in 120v
(that is the most sophisticated statement I can make about this matter at
this point and I offer it only as an indication of my level of preparedness
which is weak due to limited experience. I expect I can do this project if
I proceed cautiously).

I probably should examine a book (on setting up/modifying new existing
lines). Any suggestions regarding a book? I recall seeing a few books on
wiring at the BORGs.

Thank you,
Bill





"dpb" wrote in message
...
Delbert Freeman wrote:
...

You are right about the 240v being, essentially, two 120v lines. Unlike
120V, which has a Hot, Common and Ground, the 240 has (or can run on) 2
Hot and a Ground/Common. ...

To clarify for OP what could be misinterpreted given it appears little or
no familiarity exists...240V has _only_ two 120V 'hots' and an associated
ground, _no_ neutral.

Three wire appliance outlets (no longer NEC Code-compliant, now need four)
utilized the ground conductor as the 120V neutral as well for the 120V
(components like motor, light, etc.) but the 240V heater coil is tied
directly across the two hot and isn't anywhere connected to a "neutral".
Ditto for 240V motors; there's a third wire but it's ground, not neutral
and the motor doesn't care whether it's there or not.

To go on for OP who seemed surprised to learn what 240V comprises, the
240V is generated by tapping from a transformer at such points that one
leg is 180-deg out of phase (in time) w/ the other so when one leg is at
the positive sine peak the other is at it's negative max. The RMS
difference between these is then the 240V your voltmeter sees while each
(being AC) measures 120V to a neutral. While these are commonly called
"phases", the phase there is the time shift within a single one of the
three phase generation phases from the powerco. It's still single-phase
power.

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