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Hi,i'm new to this field,so after a few months working,i have some questions about the welding,any detailed explanation on the issues will be very much appreciated.1.) what's the purpose of the Open Circuit Voltage ( OCV ), what's the meaning behind the increasing/decresing figure in the techical data? the bigger the figure,the better it is?? i saw a statement in the product catalogue and it really beats my mind.."..available with a VRD function - offering lower open-circuit voltage for welding in dangerous environment.". therefore it gives me an impression that the high OCV is not allowed in dangerous environment.2.) Under what circumstances that we are required to use HF ignition instead of contact ignition (TIG)? what are the differences it could make when it comes to welding result?3.) Difference between Rated Power and Loading Capacity?4.) how to calculate the power factor?5.)what's the meaning of power ratio & efficiency at maximum current? and how to make the calculation?6.) in case we knew the thickeness of the material which we are going to weld, is there any formula to know the size of the electrode that we got to use? or vice versa?7. ) The amount of voltage steps  3 ~ 400 V   -  56      - what does the 56 mean and from where we can get this figure?8.) - mains cable/fuse delayed  ( 380 - 415 V ) - 4 x 2.5mm² / 16 A Delayed     - control range - 40 - 420 A / 15 - 37.5 V       i couldn't understand, if the delayed is 16 A, how could the figure in the        control range start from 40 A??9.) Welding power with only 1-knob. what does 1 -knob means?10.) some of the wire feeders are built in AC and some in DC, is there any reason for these two scenarios?11.) why does the CO² cause a lot of spatter?12.) it's pretty often that i see the material thickness measured in 'gauge' eg.       24 gauge. what's to conversion anyway, from gauge to inch,or cm, or       mm?13. ) what are the IGBT modules?Last edited by vincent; 06-26-2007 at 12:41 AM.
Reply:First the earth cooled, then.....Seriously, maybe you should start with a simpler set of questions, such as, I want to build xyzzy, what kind of machine (mig, tig, arc, oxy) would be best suited, given I don't want to spend more than $yyyyy.Not trying to be un-helpful, it just doesn't make sense if you are just thinking about welding to be worried about OCV and what not.- John
Reply:VRD is an option that sets the voltage at the leads to less than 20 or 18 so you don't get knocked on your keyster while working in dangerous enviroments.  Most OCV is in the 60 range.  When welding, the voltage hangs around 27 to 32.  The higher the open circut voltage, the steeper the slope of the welder.  This has to do with control of the arc.  Its called slope.  If the OCV is 60 and welding voltage is 30, then if you drew a line representing volts Vs Amps, it would have a certian angle to it.   If you started with 70 volts, the angle would be diffeent.  The angle of the slope has to do with the window of amps that change while you are welding.  The amps and volts change with a change of the arc length.  Steeper slope gives a smaller change of amps in the "welding widnow" of volts.Where did you get all these questions?DavidReal world weldin.  When I grow up I want to be a tig weldor.
Reply:I think we're doing his homework for him.  I never mind answering questions but theres lots of info at the suppliers sites. Start there and then come and we'll gladly clarify anything for you. Lots of smart people here willing to lend a hand, but you have to be willing to do some on your own too.Latest Toys Miller 180 Mig and Elite Mask!!Wright Welder 225ACShop OutFitters 20/20 Bending SystemHypertherm 380 Plasma30 Years of Sparking (Electrical & Welding)
Reply:Originally Posted by WolfmanJack13I think we're doing his homework for him.
Reply:yep, sounds like homework to me.....  I like the "any DETAILED explanation" part.I'm a Lover, Fighter, Wild horse Rider, and a pretty good welding man......
Reply:And please, "Compare, contrast, and give examples"Ooooh bad memories of school coming back. Don't miss those days.
Reply:allow me to clarify here that i'm not a student and i won't be getting any exam paper in my job,i report directly to my director but he's just too busy to guide me on these,and the technicians always engage on their jobs. i'm totally new to welding and i did do my homework,but the information at the web site seems abstruse for me..i just wish there's someone out there who is willing to help me in a simpler way..it's ok if there isn't any.i will work it out myself
Reply:I think what everyone is saying is the answers to your questions are too long to type. Ask one question at a time and youll have more luck with us. If your new to welding I wouldn't worry about the ocv- unless you are planning to weld in a puddle with jumpercables on your nipples, while huffing the argon from your tig torch. lol just a joke no offence. You only need to be 2% smarter than what you are working on.Lincoln pm140hacksawa big hammer
Reply:Ok I'll answer 2 of the questions.Here is a metal gauge/thickness chart:http://www.sheetmetalguy.com/sheet_m...auge_chart.htmWhat are IGBT? http://www.powerdesigners.com/InfoWe...BTs/igbts.shtmIGBT is integrated gate bipolar transistor. It is an electronic component inside the welder; why you would need to know this for welding is beyond me.- John
Reply:Guys, I want to say this without sounding paranoid, but who is this vincent guy?  I've been a flight instructor for over twenty years.  The guys who flew into the twin towers gleaned most of their information from good natured AMERICAN people willing to share their knowledge.  All of you seemed to sense something wrong with his questions anyway.  The combination of detailed question into electrical theory and his strange sentence structure makes me wonder.
Reply:If he's in this job and needs to know this information, without knowing it and without knowing how to look it up, it sounds like he's in over his head. John -  fabricator extraordinaire, car nut!-  bleeding Miller blue! http://www.weldfabzone.com
Reply:FYI - I ran an IP trace and this guy is in Singapore. Maybe he's just trying to figure out how welders work?John -  fabricator extraordinaire, car nut!-  bleeding Miller blue! http://www.weldfabzone.com
Reply:Well if he was asking the the cockpit layout of a jumbo jet or something like that I wouldn't answer him but I don't think that he's planning to attack us with a squadron of 3 phase welders. Even if he was I could out run him until he ran out of lead.Last edited by tresi; 06-26-2007 at 07:40 PM.
Reply:If we shoot one down, can we keep it?
Reply:#2 when ever you don't want the tungston to get contaminated.#9 means just what it says, only 1 knob has to adjusted to set the welding current.
Reply:Originally Posted by MAC702If we shoot one down, can we keep it?
Reply:Miller DVI2Lincoln Precision Tig 225Thermodynamics Cutmaster 38Everything else needed.
Reply:Originally Posted by tresiOne would think that but normally when we, the USA, shoot up an attacker we end up rebuilding it and giving it back.
Reply:Wow...looks like I stepped into this thread a little late. I better go put my boots on before it gets much deeper.  - Paulhttp://all-a-cart.comWelding Cart Kits and accessories
Reply:Originally Posted by tresiWell if he was asking the the cockpit layout of a jumbo jet or something like that I wouldn't answer him but I don't think that he's planning to attack us with a squadron of 3 phase welders. Even if he was I could out run him until he ran out of lead.
Reply:Saw this thread and decided to wait a little (saw what was starting and wanted to stay away for a day or two, as well as give someone a little less... pedantic... a chance  )So here's a stab at a few... Originally Posted by vincent1.) what's the purpose of the Open Circuit Voltage ( OCV ), what's the meaning behind the increasing/decresing figure in the techical data? the bigger the figure,the better it is?? i saw a statement in the product catalogue and it really beats my mind.."..available with a VRD function - offering lower open-circuit voltage for welding in dangerous environment.". therefore it gives me an impression that the high OCV is not allowed in dangerous environment.
Reply:enlpck:You answered a bunch of vincent's questions.I have to take issue with your answer #4.Power factor is the ratio of real (watts) to apparent (volt-amps) power.You showed it reversed. (watts / volt-amps should be 1 or less)John-----------------------------------|Craftsman 230/140 amp AC/DC BuzzboxSynchrowave 250
Reply:Originally Posted by PwrTurtleenlpck:You answered a bunch of vincent's questions.I have to take issue with your answer #4.Power factor is the ratio of real (watts) to apparent (volt-amps) power.You showed it reversed. (watts / volt-amps should be 1 or less)
Reply:My guess for #7 was 400volt 3 phase input. 400 volt 3 phase is common in Singapore. I'm stumped about the 56. According to my reference Singapore has 50 cycle power. I was wondering if the 56 was some misprint of 50/60 cycle.i sure am glad u typed out all that i think my fingers would have fallen off (poor little index fingers of mine) peck ,,,peck,,,peck,,,lol63' Lincoln SA200 2008 miller trailblazer 302fibre-metal pipelinermiller camo BWEand all the guns and ammo a growin boy needs
Reply:Thanks David,actually i compiled the questions myself,because sometimes when my superior is not available, i got to explain the features/technical data to the customers in the shipyards. FYI, my question is from the Kemppi Minarc 150.Where did you get all these questions?David[/QUOTE]
Reply:Thanks enlpck and others, you guys have been very helpful..yes enlpck, it's the input power/ connection voltage. for example the wire (feeder ) 400 Kempoweld is using AC 30V, while the MF29 FastMig Basic is using DC 24 V, so i do not know to way to explain in case the customers want to make the comparison.The average power cycle here is about 55,and it's variable depends on situation. as for the voltage steps, FYI tresi, i got it in the technical data for Kempoweld, as stated above, yes, 3 is stand for 3 phrase and 400V is pretty common for commercial usage, the only thing that i don't understand is the figure 56, but i think i can get a rough picture from enlpck's explanation. enlpck, i have got a clearer picture now,thanks to your understanding n patience as well s the effort to answer my questions, perhaps i need to put more effort at my welding job in the future.
Reply:Originally Posted by mcgirrtGuys, I want to say this without sounding paranoid, but who is this vincent guy?  I've been a flight instructor for over twenty years.  The guys who flew into the twin towers gleaned most of their information from good natured AMERICAN people willing to share their knowledge.  All of you seemed to sense something wrong with his questions anyway.  The combination of detailed question into electrical theory and his strange sentence structure makes me wonder.
Reply:Originally Posted by vincentThanks enlpck and others, you guys have been very helpful..yes enlpck, it's the input power/ connection voltage. for example the wire (feeder ) 400 Kempoweld is using AC 30V, while the MF29 FastMig Basic is using DC 24 V, so i do not know to way to explain in case the customers want to make the comparison.The average power cycle here is about 55,and it's variable depends on situation. as for the voltage steps, FYI tresi, i got it in the technical data for Kempoweld, as stated above, yes, 3 is stand for 3 phrase and 400V is pretty common for commercial usage, the only thing that i don't understand is the figure 56, but i think i can get a rough picture from enlpck's explanation. enlpck, i have got a clearer picture now,thanks to your understanding n patience as well s the effort to answer my questions, perhaps i need to put more effort at my welding job in the future.
Reply:I know 60 Hz here is about as close to gospel as anything.  Even 60.1 Hz is considered out of bounds and something better get fixed pronto.
Reply:i'm not sure because this's what the technician told me, he said 50-60 Hz is the standard frequency used nowadays..he also added 50 is too weak to gain a good welding result..i will check with him again over this matter.
Reply:50 or 60 Hz is standard in every place I've ever been, which is quite a bit.  But you shouldn't expect it to vary within a wide range in any particular place.50 Hz. is fine for welding.  Why wouldn't it be?  DC welding is actually 0 Hz, in a way.  What it does do though is make your transformer work a little harder and warmer so you'll have a lower duty cycle.  Or are we talking about AC GTAW?
Reply:I agree with Mac702 on this. My reference shows Sinapore having 50 Hz. Could the technician be trying to say that this machine could run on either 50 or 60 hz?
Reply:My answer to #7) was based on the word 'steps' in the phrase 'the amount of voltage steps', and presuming it refered to output. Several other more likely options have been ventured, as well. Another that comes to mind is that it was intended to be ' 400Volt, 56Amp', which would be in the ballpark for a larger industrial source.BTW: My IEEE handbook lists NO utility power suppliers in the world at a frequency other than 25Hz (still some, but I think the last in north america is shutdown or about to), 30Hz (very few, maybe all gone now), 50Hz, or 60Hz. The standard spec in the US is 60Hz, with a permissible variation maxing at 0.1Hz, a limitation on the duration of a particular frequancy excursion, and requirements for average frequency over a time period (held over from the days of mechnical clocks, where synchronous motors drove them, but still useful for synchronizing certain electronic devices). Most places in the world have similar specifications, and AFAIK, all industrialized nations do.Power from a local source may vary significantly more than that (such as from a diesel plant for a factory or a small town), often up to 5% or more averge, and even more short term under a large load change. Most gear can handle 5% variation without significant issues, but I wouldn't count on much more.