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HD
07-13-2004, 08:34 PM
My friend gave me a stick welder that he said didn't work. So I took it back to my shop and plugged it up, and it wasn't striking an ark. I started to take it apart to see what was up, and that is when I saw that it needed 220VAC single phase. Does any on know how I need to wire my house to get this? My 220 outlet is 2 phase (4 wires 2 hot at 120 VAC 1 neutral and 1 ground, right?).

I have two wires going into the house, and here is a picture of my 220 outlet:

http://ourlongfamily.com/K5/outlet.jpg

mofugly13
07-13-2004, 08:47 PM
You need a different receptacle. You only need the two hots, and ground for your welder, no neut. The two hot wires coming to your house have 220 volts across them. So, you need a two pole breaker for your panel, and take those two hot's from the breaker and a ground to your receptacle, and you should be good to go. If you have any more ???'s or need specifics, ask up. /forums/images/graemlins/thumb.gif

surpip
07-13-2004, 08:50 PM
hey im going to need to do the same setup, so there is 4 wires on that plug? how do i know wich 3 to use? its my buddys house so i dont want to mess annything up

HD
07-13-2004, 08:53 PM
Thanks for the help! /forums/images/graemlins/thumb.gif It's just weird that it would have a reguler house 120 plug on it. I will try what you said, I just may have to rest the breaker a few times. /forums/images/graemlins/whistling.gif

beater74
07-13-2004, 08:53 PM
[ QUOTE ]
My 220 outlet is 2 phase (4 wires 2 hot at 120 VAC 1 neutral and 1 ground, right?).


[/ QUOTE ] NOPE your power is single phase. all residential power is single phase.

the easyiest way to make your welder work is to buy a plug that matches the outlet.
you are correct your outlet is 2 hots with a neurtal and a ground but what you need is 2 hots and a neutral the ground is not needed.
so if you buy a matching plug you just have no ground to hook up.
but be sure to check your amperage on the welder and make sure thet that outlet will handle it by check your breaker for the amount it will handle amperage.

but you should be fine most 220 welders a 30 amp machines and most 220 residential outlets are 20-50 amps

wasted wages
07-13-2004, 09:03 PM
[ QUOTE ]
My 220 outlet is 2 phase

[/ QUOTE ] /forums/images/graemlins/dunno.gif /forums/images/graemlins/dunno.gif /forums/images/graemlins/dunno.gif /forums/images/graemlins/dunno.gif /forums/images/graemlins/dunno.gif2 phase?????






NOT!!!!!

74beater
07-13-2004, 09:31 PM
If that is a picture of your dryer recp. it is 30 amp 240v
Go to Home Boys and ask for a dryer pigtail(it's a 4 wire replacement cord with a male plug on one end and ring or fork terminals on the other)

HD
07-13-2004, 09:48 PM
[ QUOTE ]
[ QUOTE ]
My 220 outlet is 2 phase

[/ QUOTE ] /forums/images/graemlins/dunno.gif /forums/images/graemlins/dunno.gif /forums/images/graemlins/dunno.gif /forums/images/graemlins/dunno.gif /forums/images/graemlins/dunno.gif2 phase?????






NOT!!!!!

[/ QUOTE ]

Okay, well in the Navy everything on the ship is 2 phase.

mofugly13
07-13-2004, 10:13 PM
[ QUOTE ]
.... the easyiest way to make your welder work is to buy a plug that matches the outlet.
you are correct your outlet is 2 hots with a neurtal and a ground but what you need is 2 hots and a neutral the ground is not needed .
so if you buy a matching plug you just have no ground to hook up.
but be sure to check your amperage on the welder and make sure thet that outlet will handle it by check your breaker for the amount it will handle amperage.

but you should be fine most 220 welders a 30 amp machines and most 220 residential outlets are 20-50 amps

[/ QUOTE ]

Dude, I hope you meant to say that the neutral is not needed. It's a BAD idea not to ground anything electrical, especially a welder. That's your safety net. Anyway, like someone said, the easiest thing to do would be to buy a dryer pigtail at home depot. Then, swap that to your machine, just don't hook up the white wire. If you change out the receptacle, the groun ALWAYS lands on the green screw.

mofugly13
07-13-2004, 10:20 PM
surpip. See that picture of the receptacle in the first post. The hots are on either side, the neutral is on the bottom and the ground on top. If you are going to be putting in the correct receptacle for your buddy, just hook the hots in the box to their two terminals, and put the ground under the green screw. Cap off the white (neutral) and tuck it back into the box. Good luck. /forums/images/graemlins/thumb.gif

84_Chevy_K10
07-13-2004, 10:40 PM
[ QUOTE ]
Dude, I hope you meant to say that the neutral is not needed. It's a BAD idea not to ground anything electrical, especially a welder. That's your safety net. Anyway, like someone said, the easiest thing to do would be to buy a dryer pigtail at home depot. Then, swap that to your machine, just don't hook up the white wire. If you change out the receptacle, the groun ALWAYS lands on the green screw.

[/ QUOTE ]

Uh....glad you're not wiring anything in my house.

Ground is your safety net, like you said. That means that current should flow from the hots, through the load, and to the neutral. Whether the machine is grounded or not is a moot point, the main point I am making here is that having current flow to ground is unacceptable unless there is a wiring emergency.

220 is two hots + a neutral

Although I do not have a lot of experience with 220, I do know that having current flow down the ground is an unacceptable (and in most places, illegal) way of wiring things.

Does it work? Yep. /forums/images/graemlins/rotfl.gif

HarryH3
07-13-2004, 10:49 PM
Post deleted by HarryH3

Xtreme Off-Road
07-13-2004, 10:54 PM
Most welders do not use the neutral. They use the 2 hot and ground. The neutral is only required if the appliance/equipment needs 120V. If you look at most mig, tig or buzz box plugs, they look like a big version of your standard wall plug. The big difference is that the 2 flat blades are hot and as in all plugs the "U" shaped one is ground.

84_Chevy_K10
07-13-2004, 11:01 PM
[ QUOTE ]
The point is that the case of the welder should be connected to ground. If one of the hot wires should touch the case, and the case is not grounded back through the ground connector, then the first person that touches the case while also touching anything that is grounded will complete the circuit. /forums/images/graemlins/yikes.gif

If the case IS grounded and a hot wire touches it, then the circuit breaker back at the panel (or the GFI breaker, if it's set up with one) should blow rather than shocking the pi$$ out of the operator. /forums/images/graemlins/eek.gif

[/ QUOTE ]

I agree with you 100%. The case should be grounded.

However....

I have nearly 2,000 pages of electrical code here in my dad's book, and I have NEVER heard of wiring something to have current flowing down the ground line all the time and not using the neutral. That is electrially unacceptable in my opinion.

Bruiser
07-13-2004, 11:09 PM
Actually you are partial correct, but some fans use 120 in welders so the nuetral is need, just like in your stove, it is 220 but uses 120 for the lights and timers. The correct way to do this is if you have a 4 wire receptacle to put in a 4 wire plug and remove the grounding strap that will between your nuetral and ground where the plug connects. That is the difference between a 3 wire and a 4 wire, is a little strap that jumpers the nuetral to your ground. If you do not remove this it creates a parallel circuit and can cause everything in your house that is grounded to have current on it. If you are not comfortable with this contact your local Electrician or send me a private message and will try to explain better and find you some pictures.

2nd Year Electrical Apprectice

Another note if you have a 4 prong receptacle as you do it is against the National Electrical Code(NEC) to change it to a 3 wire receptacle, you must change the cord on the equipment to a 4 wire cord.

Xtreme Off-Road
07-13-2004, 11:12 PM
The Welder does not flow any current down the ground. Ground is only connected to the steel body. The welder gets its power from the 2 hot leads. Each lead is 120V to neutral, but they are 180 degrees out of phase from each other. So if you measure from one hot to the other you will see 240V. The neutral is not needed and no current will flow to the ground.

m j
07-13-2004, 11:15 PM
[ QUOTE ]
you are correct your outlet is 2 hots with a neurtal and a ground but what you need is 2 hots and a neutral the ground is not needed.


[/ QUOTE ]

Ground is ALWAYS needed

m j
07-13-2004, 11:19 PM
[ QUOTE ]
220 is two hots + a neutral

[/ QUOTE ]

nope
220 is just 2 hots
the Neutral is needed only if you want to run a 110/120 whatever in the same machine, like a fan or timer as was mentioned above
if the device is entirely 220 no Neutral is needed and the ground is merely to give a 'short' a path other then you for safety

Bruiser
07-13-2004, 11:21 PM
It is true you may not need it but it is still hooked up, the 3 wires in a 3 prong is 2 hots and a nuetral. The ground is jumpered to the nuetral where the cord connects to the machine. Older homes did not have a groundingsystem hence, only a 3 wire system. There was no ground.

m j
07-13-2004, 11:28 PM
ground - Neutral gets fuzzy as they do end up in the same place

but I have never seen a 220 device that had a 3 prong and split into 120
3 prong to my knowledge is a straight 220 appliance with no Neutral
WTF do I know, I am scared of 'tricity and fire and sharp things

surpip
07-13-2004, 11:32 PM
[ QUOTE ]
[ QUOTE ]
[ QUOTE ]
My 220 outlet is 2 phase

[/ QUOTE ] /forums/images/graemlins/dunno.gif /forums/images/graemlins/dunno.gif /forums/images/graemlins/dunno.gif /forums/images/graemlins/dunno.gif /forums/images/graemlins/dunno.gif2 phase?????






NOT!!!!!

[/ QUOTE ]

Okay, well in the Navy everything on the ship is 2 phase.

[/ QUOTE ] not everything on the boat the power outlets for the jets are 3 phase

m j
07-13-2004, 11:37 PM
oh, and just how old do you have to go to have no ground in a house? 1930s?

Bruiser
07-13-2004, 11:53 PM
I live in a rural area that most of the houses were built in the 50's and don't have a grounding systems.They didn't even start making equipment with 3 prong plugs until late 50's and it was much later will it actually took off and was required. Don't know exact year I let someone borrow my school notes to study for is E.J-test. I even went to one house a while back to help my plumber friend and it still had the old knob & wire but wasn't in use anymore they had switched to a newer type panel. I still have screw in fuses in my current house. 3 Subpanels, one with screw in fuses for a dryer (3 prong no ground) and 2 that have actually breakers one for a electrical heater and other for a water heater. Last house I lived in had a panel with breakers but still no ground system.

Found it 1975 was first year new houses were required to have 3 prong receptacles with ground system. /forums/images/graemlins/eek.gif

Xtreme Off-Road
07-14-2004, 12:27 AM
Go to this site, http://www.leviton.com/sections/techsupp/diagrams1.htm
Leviton may know a thing or 2 about plugs.
My welders, as most large welders do, uses a 6-50R.
No neutral and electrical code compliant.

JK5
07-14-2004, 06:46 AM
You guys AREN'T GOING NEAR MY HOUSE!!! LOL /forums/images/graemlins/tongue.gif

Before you get started....
Check wire size...breaker size...etc..
also make sure you use a outlet that is rated for the amperage pulled by the welder..

There's a little more to it then changing a plug..
I'd be carefull..you don't need any fires!!! /forums/images/graemlins/whistling.gif

m j
07-14-2004, 07:56 AM
[ QUOTE ]
for a dryer (3 prong no ground)

[/ QUOTE ]

so what part of the dryer uses 120 power?
the 3 prongs are 120 / 120 / ground
unless you say the timers run on 120v using the third wire as a Neutral you arent convincing me
2 prong 120v doesnt mean there is no ground system
I also lived in an old house with the glass insolators and wires strung by twisting them to the glass

mofugly13
07-14-2004, 08:12 AM
My casa was built in 1949 with knob and tube wiring. None of the receptacles in the house were grounded EXCEPT the ones in the kitchen, bathroom, and garage, and this was done by taking a bare copper wire from the grounded receptacle and soldering the other end to the closest watr pipe. It's how they used to do it.

Tim, a STRAIGHT 220v circiut is just two hots and a ground. As someone mentioned, the hots are 180 degrees out of phase, so the current comes out on one hot and goes back on the other, but since were talkin AC it the current actually changes direction 60 times a minute, hence 60 hertz (cycles per second). Not all circuits require a neutral. I hook up electrical all day, 5 days a week. I did a 5 year apprenticeship, and I've been a JW for four years now. So I have nine years in the trade. So, along the way, I learned a little bit about electricity.

Also like someone mentioned, it's not as simple as just swapping out a receptacle. Breaker size and wire size are critical to a safe install. Since he is changing out a 30 amp dryer receptacle, he'll prolly be alright. My 175 amp mig requires a 50 amp receptacle, tho.


Electricians do it 'till it Hz!

Bruiser
07-14-2004, 08:16 AM
[ QUOTE ]
Go to this site, http://www.leviton.com/sections/techsupp/diagrams1.htm
Leviton may know a thing or 2 about plugs.
My welders, as most large welders do, uses a 6-50R.
No neutral and electrical code compliant.

[/ QUOTE ]

Have you actually opened up one in the back? You will find that there is a bond strap from nuetral to ground. If there is any 120 volt usage (which on a dryer or a stove there will be for lights and timers) it will go back to the panel on this wire. They may simplify it and say it is a ground but IT CAN AND IN SIME INSTANCES WILL HAVE CURRENT ON IT so you must be carefull since saying it is a ground wire is misleading.

84_Chevy_K10
07-14-2004, 08:40 AM
[ QUOTE ]
Tim, a STRAIGHT 220v circiut is just two hots and a ground. As someone mentioned, the hots are 180 degrees out of phase, so the current comes out on one hot and goes back on the other, but since were talkin AC it the current actually changes direction 60 times a minute, hence 60 hertz (cycles per second).

[/ QUOTE ]

Yep, further research agrees with you. Having worked with so many electronic circuits I never think of things that way. /forums/images/graemlins/rotfl.gif But yes, you're correct, no neutal is required because current does not need a path back to the source with the other hot 180* out of phase with it.

And, of course, grounding the case is necessary for safety.

I understand now completely.

Having current purposely flow down a ground line is certainly an unacceptable practice, but if the wire has two hots and a ground, unless there is a problem with the operation, it should never flow down the ground.

justinf
07-14-2004, 09:03 AM
Okay, the first thing to do is check out the welder and see if it is a 3 wire or 4 wire equipment. If the cord does not have the required number of conductors, replace it with a properly sized cord with the correct plug on it. Replace the receptacle with a receptacle that matches the plug. Check breaker sizes and ratings of the cord, circuit conductors and plug receptacles to ensure they are properly sized and protected.

Now, if it is a 3 wire, and third wire is bonded to the metal case of the welder, this should be a ground, newer welders should not use this as a neutral. Neutral and ground are not the same. Older welders may do this, but it is not an ideal situation.

Answer this for me, if you are using the ground, that is bonded to the metal case for a neutral for a 120V circuit, there will be some current on that ground/neutral, including the case. Wouldn't this cause the case to be energized, thereby shocking someone who touches it?

yes, this can happen, I've seen instances where a neutral was incorrectly bonded to ground out in a circuit, this backfed current through the ground system, and the person's kitchen sink was live, they got shocked everytime they touched it.

I believe the idea on dryers using 120 to run the timer is false, If I remember correctly, there is a stepdown transformer, 240VAC to 12 or 24VDC. I will have to look at my dryer a little closer to be sure.

When I am preparing plans for projects, if I am feeding a 240V load, it gets 2 hots and a ground, not a neutral. If it is 240V, with 120V control, it either gets 2 hots, a neutral and ground, or it gets 2 hots and a ground, and the 120V control is fed by a separate circuit with 1 hot, neutral, and a ground (the ground may be shared between the 240V circuit and 120V circuit only if the circuit conductors are ran in the same conduit or multiconductor cable.

Any questions, please ask away. If you need help sizing conductors, breakers, etc. let me know, I'll give you a hand.

HD
07-14-2004, 09:55 AM
Thank you everyone for the help. My welder is just a small ark welder that pulls 25 amps. So my 30 amp plug will be fine. My washer and dryer is a stackable unit, so the washer gets its 120 from the 220 plug. So yes the neutral is needed for my washer and dryer.

The reason that I thought that my power was two phase is because I know that one leg is 180* out of phase with the other. I guess I need to look a little into some basic AC theory.

diesel4me
07-14-2004, 10:30 AM
I put a plug on my welder that matches the one on our clothes dryer--and made a long extension cord out of 10 gauge romex cable to reach the welder--this works well up to about 100 amps,if I turn it up higher than that the breaker will trip,since its a 30 amp curcuit to the dryer,but I have welded everything I needed to,even heavier metal like frames,etc,without needing much more then 75 amps.I dont use it a lot,or everyday,so this was a way for me to avoid running a whole new outlet and breaker to the garage--my friend used his electric stove outlet the same way--his is a 50 amp outlet for the stove,so he can use his welder at higher amp setting with no problems--I get by with mine no problems--except when someone wants to dry the laundry. /forums/images/graemlins/rotfl.gifI never realized how many different 220v outlets and plugs there are till I went to hook up the welder! /forums/images/graemlins/eek.gif /forums/images/graemlins/yikes.gif--I would say its best to consult an electrician if your not sure about the wiring--your house insurance may not cover any damage caused by improper wiring installed by a non licenced person!.

Bruiser
07-14-2004, 11:22 AM
Really all you need to do is put a 4 wire plug on your welder, we can discuss theory and "what has been done before" forever. Yes they still make 3 prong receptacles and they are still in use but new installations in "residential wiring" they must be of 4 prong type. You can not put a 3 prong reptacle where there was a 4 prong without breaking code compliance (therefore voiding your fire insurance with most companys).

The thing I was trying to get at when I got sucked into this discussion , is , if there is a bonding strap on the back of the welder that bonds the nuetral to ground then this must be removed (or creates a parallel circuit halving resistance along wire and if there is any current it will split between the two paths which can be bad , this is ohms law and fact)

A lot of appliance installers forget to do this(or don't know too) and it can cause other issues.

On 3 prong instillation the ground wire goes straight back to the panel and is bonded to the nuetral so it is not a issue.

justinf
07-14-2004, 11:41 AM
I agree with what you are saying except that it's not an issue since the ground and neutral go back to the same place. The ground and neutral do terminate on the same bus in the panel, however they serve different purposes in the circuit, so one wire can not and should not serve as both neutral and ground, it will work, but it's not properly grounded, and the potential for getting shocked or starting a fire is increased.

HD
07-14-2004, 04:59 PM
I got the dryer cord from Home Depot today. 2 hots and ground and it worked great. Thanks for all your help! /forums/images/graemlins/thumb.gif

Now I just need to practice /forums/images/graemlins/weld.gif

mofugly13
07-14-2004, 06:54 PM
[ QUOTE ]
Having current purposely flow down a ground line is certainly an unacceptable practice, but if the wire has two hots and a ground, unless there is a problem with the operation, it should never flow down the ground.



[/ QUOTE ]


/forums/images/graemlins/thumb.gifRIGHT! /forums/images/graemlins/thumb.gif

MR4WD
07-14-2004, 07:43 PM
[ QUOTE ]
[ QUOTE ]
Tim, a STRAIGHT 220v circiut is just two hots and a ground. As someone mentioned, the hots are 180 degrees out of phase, so the current comes out on one hot and goes back on the other, but since were talkin AC it the current actually changes direction 60 times a minute, hence 60 hertz (cycles per second).

[/ QUOTE ]

Yep, further research agrees with you. Having worked with so many electronic circuits I never think of things that way. /forums/images/graemlins/rotfl.gif But yes, you're correct, no neutal is required because current does not need a path back to the source with the other hot 180* out of phase with it.

And, of course, grounding the case is necessary for safety.

I understand now completely.

Having current purposely flow down a ground line is certainly an unacceptable practice, but if the wire has two hots and a ground, unless there is a problem with the operation, it should never flow down the ground.

[/ QUOTE ]

So, you're agreeing then that phasing is 180 out?

Physically impossible. Check your phasing at the tranny. Depending on where you live it may be anything from 44-4.16kv to 120.

It may be 3 phase or single phase, but either way (208-120 or 240-120). You can take two legs from that and have 240. Just because you have two hots, a neutral and a ground don't assume the phases are 180 out. A, B and C are all 120 degrees apart, therefore if you have a bug with 22.9/13.8 on the primary, you'll have 600/347 for example on the seconday. Unless it's delta (and you have an unestablished ground) it'll be 600 to ground.

It's impossible to plug a single primary phase into a can and get 2 or more phases out of it. You may have 6 legs for example, depending on how the transformer is tapped (2 hots and a neutral is common) but you will only have 6 single phases coming out.

Somewhere in philly and somewhere in cincinatti there are generators pumping out dual phase, but that's very old and obsolete. All consumer grade power in north America is 3 phase.

If you drop a phase because of a bird, or lightning for example your motors won't work but your lights may. That's still called single phasing, because in order for the delta triangle to be complete you need 3 points. 3 lines between the points. If you drop 1 point, you drop 2 lines and there for are back to single phase...

Also, for the dude that said something about wires being twisted to his house, that's called "mauling". I can do that with primary or secondary voltages to this day. Although, it's much easier to use a preform, service grip or bethea.

Is there anything else you would like to know about power transformation and distribution?

84_Chevy_K10
07-14-2004, 08:26 PM
[ QUOTE ]
Physically impossible. Check your phasing at the tranny. Depending on where you live it may be anything from 44-4.16kv to 120.

It may be 3 phase or single phase, but either way (208-120 or 240-120). You can take two legs from that and have 240. Just because you have two hots, a neutral and a ground don't assume the phases are 180 out.

It's impossible to plug a single primary phase into a can
and get 2 or more phases out of it. You may have 6 legs for example, depending on how the transformer is tapped (2 hots and a neutral is common) but you will only have 6 single phases coming out.

[/ QUOTE ]

180* or 120* is a moot point in my opinion. Point is that the voltages are out of phase with each other.

As to the 2nd point, you're absolutely correct. No way to create two phases of power from one. That makes no sense to even think such a thing in my opinion. If there is a way, I've certainly never heard of it.

Xtreme Off-Road
07-15-2004, 12:03 AM
[ QUOTE ]
It's impossible to plug a single primary phase into a can and get 2 or more phases out of it. You may have 6 legs for example, depending on how the transformer is tapped (2 hots and a neutral is common) but you will only have 6 single phases coming out.

[/ QUOTE ]

You may want to do a little more research. Like maybe at www.howstuffworks.com (http://www.howstuffworks.com)
Single phase consumer power is line A and line B 180* out of phase. And it is generated by a single line fed into a tansformer that hangs on the pole outside your house.
Read this..... http://science.howstuffworks.com/power9.htm

84_Chevy_K10
07-15-2004, 12:08 AM
I hope he is quoting RMS figures anyyway. I've been racking my brain trying to figure out how you can get 240 volts RMS from two phases 120* from each other.

As to that site you linked to, it still does not explain how a transformer creates two phases. It also states that some distribution boxes have two phases right there.

Considering there is no way to speed up or slow down the flow of electricity, how can you create two phases from one with a transformer?

Xtreme Off-Road
07-15-2004, 12:15 AM
If you look at the page again, you will see the transformer diagram. It is just a matter of windind the 2 coils on the secondary side in the opposite directions. Yes this is still a single phase output, but they are 180* out of phase from each other. Commonly refered to as line A and line B.

MR4WD
07-15-2004, 03:12 AM
[ QUOTE ]
If you look at the page again, you will see the transformer diagram. It is just a matter of windind the 2 coils on the secondary side in the opposite directions. Yes this is still a single phase output, but they are 180* out of phase from each other. Commonly refered to as line A and line B.

[/ QUOTE ]

I'm afraid you misunderstand. It's impossible to have anything 180 degrees apart when you apply 3 phase to it. It is however possible, to create a short (and derive power from it) across two seperate windings in the can.

THAT will make you think you have 180 degree phase seperation.

Edit- it's not line A and B, it's X1, X2 X3 and X0, or just X1 and X2.

tim, multiply 120 by (I think) 1.67 and then by two to get the peak voltage of 240. I'll check tomorrow when I'm way more soberer.

84_Chevy_K10
07-15-2004, 07:51 AM
Um, no. When referring to AC you never quote peak power. If we're talking about 240 volts running into a house, that is RMS, not peak.

justinf
07-15-2004, 08:34 AM
[ QUOTE ]
It may be 3 phase or single phase, but either way (208-120 or 240-120). You can take two legs from that and have 240.

[/ QUOTE ]

Two legs from a 120/208, 3 phase system does not give you 240V, it gives 208, because the phases are 120* out of phase with one another.

A single phase transformer uses two legs of the primary line. The coil is wound such that you get 240V across the coil, then the coil is center grounded, this is the neutral that runs into your house.

The two phases in a typical house are 180* out of phase, because of grounding the center. If you plot the waveforms, they have to be in order for the voltage to be 240V. The voltage waveform on both phase conductors is the same, a sine wave, with the same peak values. So, since the voltage between two points is the difference in potential at those points, the phases must be 180* apart. I will double check my points above later today, but off the top of my head, this is what is happening. Transformers do cause phase shifting which will cause the two primary phases which are 120* apart to shift to 180* apart.

Like I said, I will double check my points and post up later. /forums/images/graemlins/thinking.gif

84_Chevy_K10
07-15-2004, 08:40 AM
[ QUOTE ]
Two legs from a 120/208, 3 phase system does not give you 240V, it gives 208, because the phases are 120* out of phase with one another.

[/ QUOTE ]

Thank you. /forums/images/graemlins/bow.gif