Three phase power has three "hot" wires, 120 degrees out of
	phase with each other.  These are usually used for large motors
	because it is more "efficient", provides a bit more starting torque,
	and because the motors are simpler and hence cheaper.

	You're most likely to encounter a 3 phase circuit that shows
	110 volts between any hot and ground, and 208 volts between
	any two hots.  The latter shows the difference between a normal
	220V/110V common neutral circuit, which is 240 volts between the
	two hots.  There are 3 phase circuits with different voltages.

	Bringing in a 3 phase feed to your house is usually
	ridiculously expensive, or impossible.  If the equipment you
	want to run has a standard motor mount, it is *MUCH* cheaper to
	buy a new 110V or 220V motor for it.  In some cases it is
	possible to run 3 phase equipment on ordinary power if you have
	a "capacitor start" unit, or use a larger motor as a
	(auto-)generator.  These are tricky, but are a good solution if
	the motor is non-standard size, or too expensive or too big to
	replace.  The Taunton Press book ``The Small Shop'' has an
	article on how to do this if you must.

	Note that you lose any possible electrical efficiency by using
	such a converter.  The laws of thermodynamics guarantee that.


User Contributions:
Dev
Dec 21, 2011 @ 12:00 am
In a fire protection circuit, circuts are shown witha no example 6,8,4etc. what it mean?these circuits are connected between smode detector,junction box etc
kevin
Dec 24, 2011 @ 12:12 pm
My daughter dropped a small necklace behind her dresser. The necklace crossed a plug terminal and shorted the receptacle.

I bought a new receptacle and installed the same. I still have no power  I suspect there could be a bigger problem,this is aluminum wiring.

I've killed the breaker and call an electrician but am curious as to what happened.P.s. there is a dimmer switch on the same circuit.
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