Isn't the 220 just two 'legs' of 110? I have heard this called two phase. I confused what I was saying about the cord with wiring the female side of the plug. So in the cord are the neutral and ground considered the same thing?

 

220 volt with 2 - 120 volt legs would be called single phase. Most all 3 wire cord is produced with a black, white and green wire. To use the cord as a 220 volt cord the black and white will be your 2 - 120 volt legs and the ground will be the green.

 

OK. Thanks for clearing that up for me. I should be the one asking this question instead of trying to answer it

 

I've always heard it called 2 phase too.....

 

I would just stick a coat hanger in the slots.

 

when they talk about "phase" it is the way the power is delivered. ac is alternating curent. that means 1/2 the time the current is flowing one way and 1/2 the time it is flowing the other way. the voltage/current is following a sinewave. it looks like the top chart here.



the up and down of that chart is voltage/current. the sideways is time. the center of that wave is 0volts/current. it goes to something like 169volts above center than it goes below the center line and goes to 169volts in the oposite polarity. on average it is pushing 110volts and that is what you see if you check it with your volt meter.

a 220v single phase circuit looks exactly the same just higher peeks. both of these are what you would see in a house.

a 3phase circuit will have 3 sinewaves all going at the same time but peeking at slightly diferent time and equaly spaced apart. here is a pic, just the top part of this pic.



if you could see the electriciy going into a 3phase motor the 3 waves would look just like that pic. each peeking at diferent times.

i probably didn't explain that very well but if you could look at a picture of the power there is single phase with one sinewave and 3 phase with 3 sinewaves. there is no 2 phase(2 sine waves)

most 220v apliances like that welder do not need a neutral. the only reason to need a neutral is if some of the parts in the welder are 110volts like the controler or feed motor. if there are parts of the welder that do need 120volts then you are suppose to have a 220/110 cord end and a 4 wire cord. that will give you 2 hots, 1 neutral and 1 ground.

they used to use the ground for small 110volt loads like the light in your oven. the oven is 220v but the light is 110volt. it should have a 4 wire cord but they only used a 3 wire wich means they were using the ground wire as the neutral for that light bulb. they dont do that anymore. now they put 4 wire cords on ovens/dryers or figure out a way to feed that light bulb with 220volts.

 

I appreciate you taking the time to explain this to me. I was taught that there are 2 sinewaves if 110 going into your house and you run all your 110v stuff from one leg or the other and the load should be balanced 50% on each leg. I was also taught that the 220v in your house is a result of using the two out of phase legs of 110v together. I'm doing some wiring in my garage right now with the help of an electrician friend (not the one who taught me this stuff^) so this will really help me out.

 

everything you said there is right.

the thing is the two 120volt sine waves are exactly out of phase with each other and if you look at a picture of them measuring between the 2 hots you end up with just one wave but with higher peeks. if i was any good with photoshop i would make a pic but that would take me 2 hours to do.

whats really interesting to me is when you get into 3 phase power. with single phase you have 2 110volt ciruits and between they you end up with 220volts just like you would expect. with 3 phase if you measure between any 2 of the 110volt circuits you end up with 208volts. less than double. it's because the sinewaves are not exactly 180deg out of phase with each other. they are only 120deg out of phase. for example look at the 3 phase pic. look at when the black line peeks. then look at were the red line is at that exact same time. it is on it's way back up all ready. the diference between those two is less than if it were 2 waves exactly 180deg out of phase.

 

 

electricity 101 lol Lots of good info there, just learned a lot more about electricity then I would have thought I would. Thanks for explaining things.