Maine farmer Posted March 28, 2011 Report Posted March 28, 2011 Back in college, I had to take an electrical engineering class, ELE 215, and I got through without much trouble and a B average, but even though I never fully uderstood how three phase power worked, and I have yet to find an explanation that gives me that "Aha!" moment. Getting the right answer from solving equations does not give me the understanding that I want. Anyone got any suggestions or explanations? One thing I have noticed is that three phase motors cost less to purchase than single phase. Why? Quote
joekgamer Posted March 28, 2011 Report Posted March 28, 2011 At the power station, an electrical generator converts mechanical power into a set of three alternating electric currents, one from each coil (a.k.a. "winding") of the generator. The windings are arranged such that the currents vary sinusoidally at the same frequency but with the peaks and troughs of their wave forms offset to provide three complementary currents with a phase separation of one-third cycle (120° or 2π/3 radians). The generator frequency is typically 50 or 60 Hz, varying by country. (See Mains power systems for more detail.) Large power generators provide an electric current at a potential which can be a few hundred volts or up to about 30 kV. At the power station, transformers step this voltage up to one suitable for transmission. After numerous further conversions in the transmission and distribution network, the power is finally transformed to the standard utilization voltage for lighting and equipment. Single-phase loads are connected from one phase to neutral or between two phases. Three-phase loads such as larger motors must be connected to all three phases of the supply. Hope this helps! link: http://en.wikipedia.org/wiki/Three-phase_electric_power Quote
Maine farmer Posted April 1, 2011 Author Report Posted April 1, 2011 Hope this helps! link: http://en.wikipedia.org/wiki/Three-phase_electric_powerThanks, your reply is somewhat helpful, though I haven't gone to the link you provided just yet. The trouble with college was that it was so easy trying to get the answers that I didn't always take the time to understand the answers. Quote
athinker Posted April 23, 2011 Report Posted April 23, 2011 Thanks, your reply is somewhat helpful, though I haven't gone to the link you provided just yet. The trouble with college was that it was so easy trying to get the answers that I didn't always take the time to understand the answers. Here's an analogy that may help you understand. Consider a hacksaw with teeth 1/8 inch apart. Big teeth. The blade is 1/16 inch thick. If you make the teeth only 1/32 inch apart then you can make the blade 1/64 inch thick. You will still have the same tooth contact area per inch as the thicker blade. But with a thinner blade you will use less material for the blade. You be removing less material from the cut, less waste. you will be cutting smoother with the pressure on 4 teeth rather than one per eigth inch, And you will be cutting faster through the cut because wou will be removing the same amount of material as the thicker blade from a thinner slot. Less power for the cut too. Hope that helps. Maine farmer 1 Quote
Maine farmer Posted April 25, 2011 Author Report Posted April 25, 2011 Very helpful, athinker, thank you. That is probably the best analogy I've seen. Especially hepful to me as I tend to be a visual thinker. Quote
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