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Power is calculated by multiplying the voltage times the current. When you switch from a 120 to a 240v circuit you double the voltage and half the current. But the power consumption is the same. 120v X 10A= 1200watts change to 240v and you have 240v X 5A=1200watts....Same thing. The benefit is you can use smaller wire with a 240v circuit. Smaller wire is cheaper. But NO this has nothing to do with power factor or apparent power. Power factor and apparent power has to do with highly inductive loads drawing loads of current. It is AC theroy and does not conform to DC theroy. Big factories that have high current draw using motors etc need to have a "power correction" circuit. The power company usually does this by using capacitors to cancel the inductive reactance. AC also conforms to ohms law to an extent but the term for resistance in AC theroy is impedance. If you look at the formulas when a frequency of an AC voltage is applied you can see where the power factor comes in. DC follows a straight line and in AC you have vectors involved. So at some point in AC the straight line lifts about the axis and follows the hypotenuse of a triangle which is usually a higher value than along a straight line.
Thank you. My reply was more to enforce the idea that one will be charged the same no matter if it's 1p/110v/13a or 2p/220v/6.5a and that the wire will be smaller. The electrical usage is still the same...
... it was plumbed by Ray Charles and his helper Stevie Wonder
I am not trying to argue with any one, IMO there is little reason to change it, will it hurt any thing NO, will it help any thing, it may some but I really doubt that the difference will really be noticeable unless your have a serious under wiring of the shop or the supply to the shop,
and voltage drop does not nessarly have to be in the house or shop in a city system that can have many houses on the same transformer, the transformer may be under size, the drop wires to the meter (provide by the power company may be under sized), and so on, (the block that our church building we go to was seriously under transformed and the wire the town had in there system and what they provided for a drop to the building was seriously under sized, I needed to run power conditioners on the sound equipment and computers, as the power could vary more than 30 volts in seconds, (this last fall after burning up a number of things in the building do to low voltage, they sat new transformer for the church building it self), like I said if that is the problem then possibly changing to 220/240 volts my benefit one, So Bob I am not disagreeing with you, but my guess is if you electric range, well pump, and AC, (most all that runs on 220 all ready) your internal wiring is most likely not the problem of your power drops, on start up, and my guess is your new saw motor is more start up efficient,
totally off subject, but one year when we were with out power, and were using a 3400 watt powered by an 8 hp gas motor generator. to power the place, my mother wanted to try the washing machine, (the generator was starting and running a 2 HP sub pump easely, it would seem logical it should easily run a 1/2 hp 120volt washing machine motor, we got it set up and she turned on the washing machine and that 1/2 hp motor killed that generator like some one threw a shaft in a spoked wheel, just killed it dead, (big differences on some motor construction and how much they pull for start up), My guess is your new saw has a better starting motor at lower amps,
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if you have a 110 volt, 15 amp circuit that means it's a 15 amp single pole circuit, right?
if you convert to 220 volts it halves the amps, to 7.5 amps on 2 poles, right?
is this where we get into power factors and apparent power and what the elec co is going to charge?
No,I think you are confusing poles with phases. We are talking about single phase power, even though there are two poles, it is still just single phase. The current is not divided between the two. Aside from the equiptment ground wire, there are just two wires going to the motor that delivers 240v. (No white grounded wire)
The wattage is the same no matter what (although it would run more efficiently if it was 3 phase)
Single phase found in residental homes is called a "split phase" because it grounds one phase in the middle of the single phase winding (escentially a tap that divides the 240v voltage into two 120v line to neutral)
PS; Qroking had a good post on power factor. In simplist terms; Apparent power is what you think it draws, and True power is what it really draws.