2006-12-09 04:50:23 · 4 answers · asked by senthil v 1 in Science & Mathematics ➔ Engineering
You may be thinking of 110 volt or 220 volt power, but other people may call it 120 volt or 240 volt power. The actual voltage falls within a range and depends on many factors, including the tap that the electric company selects on the transformer outside your building, the load on the transformer (which varies during the day), and the voltage drop in the wiring going to the load. The value chosen for the nominal voltage is somewhat arbitrary, and is what evolved from the early days of electricity when there was no standardization.
I would not say that electrical voltages are multiples of 11. However, there is a very good reason why 220 volt power is a multiple of 110 volt power. That is because power coming into smaller facilities, including your home, is usually two phase. The voltage from one phase to the other phase is the instantaneous sum of the voltage of each phase. Thus, if each phase is 110 volts, the voltage from phase to phase is 220 volts.
This higher voltage is used to reduce the voltage drop in the wiring for high current devices such as the electric stove in your kitchen, your electric clothes dryer, or your air conditioner. With twice the supply voltage, the current drawn by the load is cut in half. For a given size wire, the voltage drop from one end of the wire to the other is also cut in half. Taking into account that the supply voltage is doubled, the percentage of the voltage lost in the wiring is reduced by a factor of 4.
2006-12-09 06:41:33 · answer #1 · answered by Tech Dude 5 · 0⤊ 0⤋
this is rooted in history, and it hasn't been replaced because there's no reason to. yet somewhat nominal voltage is 117 or 118 volts, or two times that, not one hundred ten. Edison spent a lot time determining what voltage to apply for his gentle bulbs. Too extreme a voltage made the bulbs too complicated to fabricate. too low made it complicated to pipe the DC voltage round, because it higher the cord length. he ultimately compromised on one hundred volts. Then he extra 10 volts to allow for line drops to get a generator voltage of one hundred ten volts. .
2016-11-30 08:53:14 · answer #2 · answered by ? 4 · 0⤊ 0⤋
a very logic question that i have never considered......would it really have a reason????
2006-12-09 06:41:14 · answer #3 · answered by ahmose99 1 · 0⤊ 0⤋
They're not.
2006-12-10 01:52:44 · answer #4 · answered by JoeSalsa 2 · 0⤊ 0⤋