On Sun, 2005-09-25 at 09:19 -0700, MrC wrote: > PAUL WILLIAMSON Wrote: > > As for power supply standards, try figuring out why hospitals > > (and a select few other businesses) get 207V. I have > > absolutely no idea why, but they do. > > Most larger businesses run higher 240 voltages, because they use > 3-phase power. 3-phase is far more efficient for large amperage > circuts than the standard 2-phase we all normally use. Also, 3-phase > is a no-brainer for generator motors, due to the 3 poles on such > motors.
I'm no longer working with electrical engineers all the time, but I think MrC has the concept right, but the numbers wrong. Or I could be wrong. I think 240v is standard one phase, two leg power, which most of the US has in their house. Common 120v is one leg, to ground. Dryers and air conditioners use both legs and see 240v. 208v is three phase. And it is way more efficient for motors, etc. Some industrial/commercial lighting is 177v because that is what you get when you tie two of the three phase legs together. Hospitals also use lots of 120v circuits with special and expensive outlets. The key is that they are designed to avoid sparks, which is important since oxygen is everywhere in most hospitals and other explosive gasses (used for anesthesia, etc.) are also common. Audiophiles buy the hospital grade outlets to improve the sound of their systems. Some audiophile vendors take normal $30 hospital outlets and put them in nice boxes and sell them for $100. Nice mark up. -- Pat http://www.pfarrell.com/music/slimserver/slimsoftware.html _______________________________________________ Discuss mailing list Discuss@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/discuss
