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Why is a 240 volt welder better than a 120 volt welder?I understand enough about electricity to know that a drop in voltage will increase amps output, and more amps are needed to run larger, deeper penetrating rods. Is it because there are more volts to start with or the way that 240 voltage works? I get the feeling that 240 not needing a neutral wire has something to do with it.Any help is appreciated.
Reply:Most 130-140 amp class 110v machines want 20 amps of 115v power if not more. Most 230v machines in the 180-200 amp class will draw 24-28 amps at 230v at rated output. You have almost 4 times the amount of power available. Don't really need to look much farther than that. It's simply a matter of having more input power, thus you get more output power..No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:I understand enough about electricity to know that a drop in voltage will increase amps output
Reply:the main point that everyone is trying to say is that you have more power available. Volts x Amps = Power. The greater either the voltage or amperage is, the more power you have available, plain and simple.
Reply:The greater either the voltage or amperage is, the more power you have available, plain and simple.
Reply:I've used a MM135 and I own a MM175. Used both at the settings for solid .023 wire for 1/8". Difference between daylight and dark in weld quality. I'll take the 175 anytime. MikeOl' Stonebreaker "Experience is the name everyone gives to their mistakes"Hobart G-213 portableMiller 175 migMiller thunderbolt ac/dc stick Victor O/A setupMakita chop saw
Reply:The formula above technically applies only to a DC circuit.
Reply:As others have mentioned there are some capacity differences... but I assume you are curious as to why a 240v machine typically produces a smoother weld than a 110v machine on like settings. It has to do with how DC power is made from AC. AC it distributed as a 60Hz (or 50Hz) sine wave (hence the name alternating current). 120v is neutral to phase, one sine wave. 240v is phase to phase with two complementary sine waves. Because you have less time without voltage in a 240v circuit the DC power you produce will have less distortion resulting in cleaner power. Likewise a 3-phase machine will often produce even cleaner power yet. While this holds true for transformer machines... inverter machines have become very smooth... even off 110v power as many have large capacitors to store and release smooth power. This is why engine driven welders produce DC natively... no loss to frequency.
Reply:Originally Posted by forhire... 120v is neutral to phase, one sine wave. 240v is phase to phase with two complementary sine waves...
Reply:"forhire" I have problems with several of your statements, but I did not intend to attempt to teach basic electricity on the forum."Burnt09", Well if you want to get into welder design, inverter advantages (and disadvantages), the effects of capacitive and inductive reactance, power factor, chopper circuits,etc., we can do that, but that was not the point of my post. The OP seemed to be confused as to why a 240V welder was "better" than a 120V welder and seemed to think that the lower voltage would produce "more amps". I was trying to give him a basic understanding that he was on the wrong path about voltage and amperage. By the way, there are a lot of AC circuits where the reactance is negligable and can be disregarded from a design standpoint, incandescant light circuits for instance.
Reply:Originally Posted by davido30093By the way, there are a lot of AC circuits where the reactance is negligable and can be disregarded from a design standpoint, incandescant light circuits for instance.
Reply:davido30093:Let me explain my statement about lower voltage equalling more amps. Please correct this understanding if I am wrong in my understanding.In high tension power transmission lines, amperage goes down as voltage goes up. Conversely, you drop the voltage and the amps go back up. a welder takes a higher voltage and lowers it in such a fashion that more amperage is produced. The voltage is the force that is used to push the amperage, which is the load. DSW and forhire, between the two of them, answered my question: More power in equals more power out, and there are two sources of electricity for the machine to use to get the amperage to the rod in a 240 v cirucit where there is only one in a 120 volt machine: one hot in a 120 volt and two hots in a 240. There are fewer gaps in the power supply when using 240 volt vs 120 volt and having fewer gaps means a smoother flow of current, which means a better arc, which means a better weld, and so on.I in no way, shape, or form dispute that there is a lot of high powered math and calculations involved with electricity and the design of electrical devices but what I was trying to understand was the differences in operating principles between 120 volts and 240 volts. DSW and forhire, between the two of them, answered my question.
Reply:Power transmission lines run a high voltage to reduce power loss due to resistance and to save money by allowing smaller gauge wire.Say you want to send 12KW to your shop using a 120V circuit. to do that you'd need to push 100A. Actually, more, since you'd lose some power to the voltage drop due to the fixed resistance in the wire. Lets say that power loss is 1000W. So you need to send 13KW to get 12KW to the shop.Now send that at 240V. You need half the current so you have half the losses so 12.5KW to get 12KWKeep doing this and you can get to the voltages used by the power transmission lines.This principle is exactly why Westinghouse's alternating current eventually won out over Edison's direct current power systems.MillerMatic 252, HTP 221 w/cooler, Hypertherm PM45, Lincoln IdealArc 250 AC/DC"I'd like to believe as many true things and as few false things as possible"
Reply:Originally Posted by jarheaddocIn high tension power transmission lines, amperage goes down as voltage goes up. Conversely, you drop the voltage and the amps go back up. a welder takes a higher voltage and lowers it in such a fashion that more amperage is produced. The voltage is the force that is used to push the amperage, which is the load.
Reply:Originally Posted by jarheaddocdavido30093: ... More power in equals more power out, and there are two sources of electricity for the machine to use to get the amperage to the rod in a 240 v circuit where there is only one in a 120 volt machine: one hot in a 120 volt and two hots in a 240. There are fewer gaps in the power supply when using 240 volt vs 120 volt and having fewer gaps means a smoother flow of current...
Reply:Sweet reading this thread reminds me of electrical class.Will Supports Autism Awareness My ToysBobCat 225 PLusMillermatic 130Miller Spectrum 300 CutmateEverlast Power Tig 185 Micro April is Autism Month .
Reply:link failLast edited by Snuffy; 11-14-2012 at 01:29 PM.
Reply:Originally Posted by OldendumNo, it's one phase, one wave. There is one transformer with a center tap providing the service.
Reply:Originally Posted by KelvinThink of transmission wires (or wires in your shop) like a pipe.Voltage is analogous to PRESSURE. The higher the pressure, the more water you can get through a given size pipe in a given amount of time. The same goes for wires: The higher the voltage, the more energy (i.e., kilowatt-hours) you can push through a given size wire in a given amount of time.If you have two pipes, both running at the same pressure, and the pipes are of different diameters, you can get more water in a given amount of time through the pipe of a larger diameter. In the same way, if you have two wires running at the same voltage, you can get more energy in a given amount of time through the wire of a greater diameter (or ampacity).So voltage is akin to pressure.Ampacity is akin to "pipe diameter" or "wire diameter."(Water pressure) x (pipe diameter) = gallons per minuteVoltage x Amperage = watts = kiloWatt-hours per hour = [unit of work or unit of energy]/time = PowerThe analogy doesn't work in EVERY respect (for example, the movement of liquid through pipes is subject to the laws of fluid dynamics, unlike electrons through wire) but in many respects it does work.
Reply:If you are satisfied, I won't try to confuse you but this statement:there are two sources of electricity for the machine to use to get the amperage to the rod in a 240 v cirucit where there is only one in a 120 volt machine: one hot in a 120 volt and two hots in a 240. There are fewer gaps in the power supply when using 240 volt vs 120 volt and having fewer gaps means a smoother flow of current, which means a better arc, which means a better weld, and so on.
Reply:theoretically, you could have a 120v machine that has the equivalent output to a 240v machine. You would need to draw at least twice as much current from the 120v line to get the same output from the welder which makes them unusable to pretty much any residential consumer. 240v is much more economical and user friendly from the stand point that most people have 240v with adequate capacity to run a reasonably sized machine.
Reply:Originally Posted by davido30093The reason that a three phase welder has a "smoother" arc is primarily because of the more favorable waveshape of the three phase input power and therefore a "better" output waveshape.
Reply:This link has some good info for youhttp://www.millerwelds.com/resources/basicelec/Ed Conleyhttp://www.screamingbroccoli.com/MM252MM211 (Sold)Passport Plus & Spool gunLincoln SP135 Plus- (Gone to a good home)Klutch 120v Plasma cutterSO 2020 benderBeer in the fridge
Reply:Originally Posted by forhireI'm still vague on the center-tapped single phase waveform.
Reply:forhireYou are on the right track. Look at the waveform that you posted and you will see that, in a given period of time, the three phase waveform has a higher average voltage than the single phase wave form. In order to really understand it, you need to take a look at the basics of electricity and how a power supply works. After all, a welder is a power supply. How the current gets from the supply at the electrical panel to the output of the welder is not terribly complicated, but it can be difficult to grasp without a knowledge of basic electricity. I would suggest a good book, or a good website, and start there. Then take a look at how welders work. Understanding how inverter welders work requires a knowledge of how ac and dc circuits work as well as an understanding of solid state electronics. Most people give up long before they get that far. If you are really interested, get a good book or two and dig in. I will be happy to answer any specific questions if you get stuck on something. If it is just idle curosity, give it up. You will get boared long before you grasp enough to really be useful.http://www.millerwelds.com/pdf/Basic.pdf
Reply:There's some good info here about the 120/240 "split-phase" power. http://www.allaboutcircuits.com/vol_2/chpt_10/1.htmlOne fellow had this to add to the info in the link above:If you connected a dual trace oscope's probes' gnds to the Neutral (center tapped wire) and put one probe on phase A and the other on phase B the waveforms would be 180 degrees out of phase. When A peaks positive B peaks negative. So how is it that the A-Neutral and B-Neutral voltages are said to be "in phase"? [Of course, it makes no sense to ask about the phasing of A-B - any voltage is always in phase with itself.]The author explains that instead of supplying your house from the grounded center tapped transformer ("split phase") secondary you could substitue two series connected 120 vac single phase generators (synchronized and in phase ) and ground their tie point and have exactly the same system. They must be sychronized in phase since if they were otherwise their voltages would buck or cancel (a little like connecting batteries in series but opposite directions). Yet, if you choose the tie point (where gen 1 connects to gen2) as a measurement reference for your oscope, the other two leads supplying phases A and B in your panel would display waveforms 180 degrees out of phase, just like before. This out of phase characteristic is nothing more than the result of your choice of reference for the waveforms - you are measuring "from" the mid-point "out toward" the two opposite polarities of the winding.The bottom line is this: electrically speaking (vs. some arbitrary place we may choose for a measurement reference) the voltages across the two secondary portions are in phase. They don't buck or cancel but are series aiding - their voltages add directly with no phase angle to contend with. This is just the result of tapping a single winding right in its center point. Nothing mysterious happens. So you have a single phase (vs. some other multi-phase system like a closed delta three phase, etc.), split phase system (the secondary single phase winding is split in two, but still connected, parts by center tapping it).It's a bit like connecting two 12 Volt batteries in series. You can measure from one end to the middle and have +12V then to the far end and have +24V. Or you can put your ground lead in the middle and measure +12V and -12V at the ends. It's a matter of your measurement reference point."USMCPOP" First-born son: KIA Iraq 1/26/05Syncrowave 250 w/ Coolmate 3Dialarc 250, Idealarc 250SP-175 +Firepower TIG 160S (gave the TA 161 STL to the son)Lincwelder AC180C (1952)Victor & Smith O/A torchesMiller spot welder |
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发表于 2021-8-31 23:40:53