その前に単相交流やめろよって話だがw

1-phase
http://www.jeea.or.jp/course/contents/12120/image/dig_04.gif
http://astamuse.com/ja/drawing/JP/2006/042/445/A/000007.png

3-phase
http://www.jeea.or.jp/course/contents/12120/image/dig_06_big.gif
http://astamuse.com/ja/drawing/JP/2006/042/445/A/000005.png