Voltage Drop is a common problem on elecricity, as high as will drop by 15%, the company I work, voltage will change from 567Vav on weekday. and up 610vac on weekend. this is the fact.
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Actually. all light or Electricity power are turnning On an Off 60 time pre second in Canada,(50 times In Erou), the AC generator are 60Hz and in circular motion., 3 phase cycles 120 degree off from each other. each have on/off cycle on different angle, how ever it happen so fast. humman eye unable to see