Okay, first things first. I searched and found nothing.

I've been looking at arc welders lately. I've seen a lot of higher voltages, i.e. 200, 230, 460V welders that are single phase. I thought that the power comes in three phases to the building though. How does single phase high voltage work out?

Also, if there are some welders that can to single and others that do three at the same operating voltage such as 230, what are the upsides to each?

Thanks...and sorry about the n00bish question.

 

not really sure what you mean by " how it works out" but most shops are 3 phase which means each phase is 120 deg out of phase from one another. 3 phase is a more efficent power. 208 or 230 is the same. 460 is acheived by add two 230 volt lines. get a single phase 208 230 welder. and you can take it anywhere.

 

That still doesn't answer my question. I'm very familiar with phase offset. Can you or someone else be particularly verbose here?

Here's another question that might help you to see what I'm asking. If I get a "one phase" 230V welder, how do I use it in a shop with three phase power? If there is a three phase welder, does it have four blades on its plug connected each to their own set of windings on the transformer or something?

Is the difference between one and three phase for a building made at the power company's transformer can?

etc. etc.

 

three phase power has never really be explained very well to me either. so i gave you the short version. it would be rare to have 3 phase power at the plug on the wall. 3 phase welders are usually much much larger in amps and physical size than single phase machines. my shop is 3 phase comming into the breaker box but at the plug i have single phase 220, this shop is 10000 square feet and in an industrial park so its got what most other shops would have. are you just trying to make sure you purchase the correct welder for your phase and voltage?

 

I am not a building electrical expert, but I do know electricity fairly well. I believe a building has to be specifically wired for three phase power delivery. I believe normal houses and smaller businesses are supplied only with 2-phase power. Larger businesses use three phase simply because they don't have to pull as much current for the building and can get the advantages of less power loss from high current lines. The majority of the building uses single phase 115, but they are using different supply lines thus reducing the total current draw on any single supply line.

I'm not sure if this is what you are looking for, but here's how three phase is generated. At the power plant, the generators use three separate induction coils. Each supplying roughly 115V rms. One side of each of these is tied to a neutral line, the other side functions as a supply line. The coils are positioned at 120* phase relations.

208 Vrms is supplied by taking power from two supply lines. 208 doesn't need a neutral, per say, since it is using one supply line as a neutral and the other supply line as a feed.

Three phase, I am not as clear on but I believe the unit uses each of the supply lines and the neutral. Therefore, it would be wired with four wires. All of the internal circuitry is designed to optimize the individual supply lines.

Unless you are doing some really heavy duty welding, I don't see the purpose of using 3 phase power. A good quality 208 Welder should be able to handle anything you would run into in the automotive world.

 

Yes, I was just trying to figure out what I should use. Obviously, for my purposes, single-phase 230V. I checked up on single phase 230, and it's done with two 115 lines coming in 180 degrees out of phase. Just trying to understand other stuff. I don't need more than a 200-300A welder.

Thanks...

Maybe someone should do a write-up and put some info in the FAQ.

 

single phase is 120/240 generally, as said in a previous post this is usually used for small businesses and residential.
3 phase can be alot of combos 120/240, 120/208, 277/480. u can have both 120/240 3 phase and 277/480 in a building. the voltage used in the building is determined by the load the building is goin to be handling. you could bring in a 3 phase 277/480 volt service, take it to a transformer to drop down to 120/240 and feed a second power panel.
the advantages of using 3 phase power are simple. for example a 480 volt motor rated at X amount of HP pulls 15 amps, put that same HP rated motor on 240 volt and it pulls 30 amps.
277/480 volt buildings usually use 277 for lighting loads and the 480 volts for motors and machinery.
the original poster knows a little about 3 phase vs single phase. the amount of voltage as i said earlier is derived from the transformer. how u get the output voltage from the panel goes as so. take 1 leg (A, B or C) of a 3 phase panel and measure it with a voltmeter to ground. say this is a 120/240 volt panel. 1 leg to ground will measure approx 120 volts. now take that same voltmeter and measure the voltage between phase A and phase B, u will register 240 volts. do the same for phase B to phase C= 240, phase A to phase C=240. each A, B and C phase are all goin to register 120 volts though.
theres other voltages such as that 120/208 panel that i dont want to get into so i dont confuse u and the 208volts is a dangerous one.
if theres any more questions feel free to ask. i should be able to answer most of them.

 

just to correct u a bit 99_GS-T. the power companies around here use voltages at around 2170volts. the reason they use high voltages is because u can send high voltage along way b4 it has to be "bumped" due to the voltage drop from traveling long distances. when it reaches a pole b4 it goes to someones house then it is "transformed" down to a workable voltage (ie 120/240) thats why power lines are dangerous, high voltage for a reason.

 

Yeah, I think some of the power sources around here (the Hoover dam) send out like 50kV. I guess I was more reffering to the transformer substations and the transformers on the electrical boxes through out the neighboorhood as being part of the plant. Same difference, but your right.

 

The best thing to do is find out if you have 3 phase available. If you don't have it available, then you don't have to worry about how it works, the advantages, or anything like that...

cause if you don't have it available, you're not going to want to pay the money to get it just for a welding machine.

 

I'll be damn somebody that knows the difference between A welder and a welding machine

 

Heres a little bit about what i know.

3 phase is mostly commerical or industrial, NO HOMES have it, and if they do which is very unlikley it will be a seprate service from the single phase service since it will be 600V and have to be stepped down to 347V.

It comes in the form of 600V, some machines or lights use power this way, i know large shears, and big compressions run from 600volt. Then you run it though a large transformer and it jumps down to 347Volt, 347 is used for highbay lights.. (which can also be wired for 120) 347 is much more efficent. Just say you wanted to run 12 lights. Now 400W highbay lights, if you ran them off 120 you could only put 4 on a circuit, if you ran them off 347 you could put 12 on a ciruit because they use less of a load on 347V.. 347volt is 3 lines, black,red,blue. If you need 120V you take the black, if you need 220V you take the black and red, if you need 347 you take all 3. If you need 600V you take the power before the transformer.

Now Single Phase. It comes in as a 2 lines. Black and red. You cannot operate things requiring 600volt of 347volts. You only have 120 volt and 220 volt. For 120 you use black, for 220 you use black and red. Most welders and tools are 220. Only large machines run from 347 or 600V

Now if its 120/220 V you need a 3 wire for the 120, if its just 220 you only need a 2 wire because it dosent require a neutral.

Theres 220/120 which means you need a 3 wire, because you have to have a neutral, if its just 220 then you just need a 2 wire with no neutral.. This is SINGLE phase.

How do you run a 220V welder on 3 phase? Simple same way you would on single phase. Grab the black and red from the 347V pannel

single phase you have... 120V and 220V
3 phase you have... 120V, 220V, 347V, and 600V (before the transformer)

If you want to know what you have see how many lines you have comming in (not incluidng the white) and see if you have 3 bus bars running up the middle of the pannel.

Thats the difference

And i dont know where you people are getting this 480V stuff.. Ive been an aprentice for 3 years and never heard of 480V... Someone please educate me? Or educate yourself.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by HamiltonRex &raquo;</TD></TR><TR><TD CLASS="quote">Heres a little bit about what i know.

3 phase is mostly commerical or industrial, NO HOMES have it, and if they do which is very unlikley it will be a seprate service from the single phase service since it will be 600V and have to be stepped down to 347V.

It comes in the form of 600V, some machines or lights use power this way, i know large shears, and big compressions run from 600volt. Then you run it though a large transformer and it jumps down to 347Volt, 347 is used for highbay lights.. (which can also be wired for 120) 347 is much more efficent. Just say you wanted to run 12 lights. Now 400W highbay lights, if you ran them off 120 you could only put 4 on a circuit, if you ran them off 347 you could put 12 on a ciruit because they use less of a load on 347V.. 347volt is 3 lines, black,red,blue. If you need 120V you take the black, if you need 220V you take the black and red, if you need 347 you take all 3. If you need 600V you take the power before the transformer.

Now Single Phase. It comes in as a 2 lines. Black and red. You cannot operate things requiring 600volt of 347volts. You only have 120 volt and 220 volt. For 120 you use black, for 220 you use black and red. Most welders and tools are 220. Only large machines run from 347 or 600V

Now if its 120/220 V you need a 3 wire for the 120, if its just 220 you only need a 2 wire because it dosent require a neutral.

Theres 220/120 which means you need a 3 wire, because you have to have a neutral, if its just 220 then you just need a 2 wire with no neutral.. This is SINGLE phase.

How do you run a 220V welder on 3 phase? Simple same way you would on single phase. Grab the black and red from the 347V pannel

single phase you have... 120V and 220V
3 phase you have... 120V, 220V, 347V, and 600V (before the transformer)

If you want to know what you have see how many lines you have comming in (not incluidng the white) and see if you have 3 bus bars running up the middle of the pannel.

Thats the difference

And i dont know where you people are getting this 480V stuff.. Ive been an aprentice for 3 years and never heard of 480V... Someone please educate me? Or educate yourself.</TD></TR></TABLE>

How many terms of school have you done? I'm in my 4th year now and the buildings I'm working on is the first I've seen to use 277/480. It's for the heater coils in the concrete.

 

I havent done any schooling yet..

Ive been doing it part time for over 4 years now. My dads a master electrician, i plan to start as soon as possible.

Got any links to devices that use this type of power?

 

we just did a hospital remodel and we use 277 also for heat tape underneath the sidewalks to prevent them from freezing.
277 is generally a lighting load voltage.
480 can be used for just about anything. lights, motors, welders, anything industrial basically.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by RMF &raquo;</TD></TR><TR><TD CLASS="quote">I'll be damn somebody that knows the difference between A welder and a welding machine</TD></TR></TABLE>

haha!!! That's kinda a little thing that gets to me at times... but it's so common that I rarely say so.

Welder = person that welds for a living or is at least good enough to (not a person that CAN weld...I can count, but I'm no accountant.)

Welding machine = a machine used for welding....not a human.


Another thing that gets me... when somebody says they have a welding HELMET. It's a HOOD or possibly a shield!!! A helmet is made to protect your head, not your face.

 

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 1 2 NV &raquo;</TD></TR><TR><TD CLASS="quote">we just did a hospital remodel and we use 277 also for heat tape underneath the sidewalks to prevent them from freezing.
277 is generally a lighting load voltage.
480 can be used for just about anything. lights, motors, welders, anything industrial basically.</TD></TR></TABLE>

I asked my dad he said '277 and 480 is yankee power'

He said the only time it gets used in canada is for really old machines, and then even it has its own seperate transformer from 600V.

He said 99% of the stuff we have up here is 600, 347,220,208,120

 

yeah 277/480 is less efficient as ur guys 347/600. either way they were both designed to do the same stuff i would imagine.
our standard voltages are 120/208/240/277/480. then our service lines b4 the transformers are 4170 i believe. from what i understand my old highschool is fed with 12000+ volts.