TIG Pulsing Q

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so, i see most machines have pulsing ability in the 10-90% PWM range. this range effectively makes it seem you are either pulsing up to the high current, or pulsing down to the low current depending on which side of 50% you are at.do you pulse up or down? can you describe how using each works on the weld. is it different for DC vs AC ?
Reply:the difference is semantics whether it is "up" or "down".  DC Pulsing takes the arc from one amperage to another with a time period of T=1/f, where f=pulse frequency.  Most traditional AC pulsing is the same, so long as you realize what an AC signal consists of in the first place.  There are non-traditional AC pulsing types, but few machines have this and is relatively new. 1st on WeldingWeb to have a scrolling sig! HTP Invertig 400HTP Invertig 221HTP ProPulse 300HTP ProPulse 200 x2HTP ProPulse 220MTSHTP Inverarc 200TLP HTP Microcut 875SC
Reply:Further on this - I always wonder why no-one really seems to talk about amp pulsing with AC. Everyone plays with frequency and balance, but why not frequency, balance _and_ normal (i.e. similar to DC) pulsing? Doesn't it have a place too?
Reply:Pulsing on A/C is nice on thin items. Even with pulsing, I find it easier to run it straight down with no pulse. Dab and move. Frequency control is nice, it makes the arc more precise and controlled. It also helps with tungsten degradation, especially on higher balance levels of DCEP. A/C balance is self expanatory, just moves the arc from DCEP to DCEN.
Reply:Originally Posted by metaljongFurther on this - I always wonder why no-one really seems to talk about amp pulsing with AC. Everyone plays with frequency and balance, but why not frequency, balance _and_ normal (i.e. similar to DC) pulsing? Doesn't it have a place too?
Reply:Originally Posted by OscarI'm sure it does, but my HTP Invertig only does 10pps when on AC, lol.  Dynasty's can go upwards of 500pps depending on how much $$$ you fork out.
Reply:Originally Posted by Oscarthe difference is semantics whether it is "up" or "down".  DC Pulsing takes the arc from one amperage to another with a time period of T=1/f, where f=pulse frequency.  Most traditional AC pulsing is the same, so long as you realize what an AC signal consists of in the first place.  There are non-traditional AC pulsing types, but few machines have this and is relatively new.
Reply:First, you are going to find that welding lingo and electronics lingo do always not match up, so you will get yourself and others confused quickly here.Most pulses in welding refer to pulse amperage or background amperage.  Both are usually the same thing.  Background amperage represents an "drop" in amps compared to the normal welding current.  Pulse amps can refer to the same thing, or represent a "rise" in welding current...But the way most machines are configured, background amps (pulse amps) are represent by a percentage of "welding amps", which are the amps that you set for the high (peak) side.  This means that pulse amps in the situation, are always a value less than welding amps.A pulse setting of 10% yields a pulse  amp value that is 10% of selected welding amps.   A pulse setting of 90% yields an value that is 90% of selected welding amps.  In other words if welding or normal peak current amps is set for 100, and you select 10% then your base amp (low amp) portion of the pulse is 10 amps and your high part of pulse (peak) will be 100 amps.A percentage based pulse works well with foot pedal setups as it means you'll get consistent average amp rise.   Some systems use a true amp value for the pulse, which use a fixed amperage for the pulse amp value.  This usually results in the foot pedal controlling only 1/2 of the pulse value, and can essentially ends up acting as a variable pulse amp control instead of controlling both current values simultaneously.Pulse is simply a tool used to control the heat.  Don't try to over think it.Last edited by lugweld; 05-23-2014 at 11:44 AM.Esab Migmaster 250Lincoln SA 200Lincoln Ranger 8Smith Oxy Fuel setupEverlast PowerPlasma 80Everlast Power iMIG 160Everlast Power iMIG 205 Everlast Power iMIG 140EEverlast PowerARC 300Everlast PowerARC 140STEverlast PowerTIG 255EXT
Reply:When you refer to pulse width, then you are referring to the relative amount of time during one pulse cycle that the unit spends in the high stage of the pulse versus the low amp stage of the pulse.  It can be set up as a 0 point type pulse which 0 is set at a 50/50 ratio setting and a negative/positive integer number line ranging for 0 to 50 or 0 to-50.  But it is almost always referred to the pulse part as a percentage of full on time.   Some refer to it as-Pulse balance-Pulse Time on-Pulse width-Pulse Duty CycleAll refer to essentially the same idea or concept.So a pulse on time of 90% (or 10%...depending upon how it is oriented by the mfgr) represents the pulse staying in the low stage (background amp or base amp stage)  90% of the time during one full pulse cycle.Last edited by lugweld; 05-23-2014 at 11:46 AM.Esab Migmaster 250Lincoln SA 200Lincoln Ranger 8Smith Oxy Fuel setupEverlast PowerPlasma 80Everlast Power iMIG 160Everlast Power iMIG 205 Everlast Power iMIG 140EEverlast PowerARC 300Everlast PowerARC 140STEverlast PowerTIG 255EXT
Reply:Some very good info in this thread. I am new to pulsing and have not had very much experience with it.L-tec Heliarc 306Miller 210Victor O/A rig
Reply:Originally Posted by welding_kidits not semantics. if the PWM maps to high-side current then 10% is really a 90% pulse down, and 80% is really a 20% pulse down. i am wondering what the advantages are to say 10% vs 90%? does most pulsing do a better job when pulsing down in the 10-50% down times?in other words, do you pulse down to take away some heat, or do you pulse up from that puddle amp to make a short blast?
Reply:Originally Posted by OscarI think I see what you're getting at.  You're talking specifically about DUTY CYCLE.  I have a gut feeling that when you say "take away some heat", you are envisioning a peak arc time greater than 50% of the pulse period, and when you say "pulse up from that puddle amp" you are envisioning a peak arc time less than 50% of the pulse period.  (what gave it away was the use of the word "short").  I am right, aren't I?
Reply:What is your background amps set at?  Which unit are you talking about?  Again, MOST units when you adjust the pulse amps, set it as a percent of the main amperage control knob.  This is never expressed as greater than 100%.In the same vein, the actual pulse stage of the cycle ( balance/width/time on) is set as a percent of full width.You are only dealing with one setting, when there are actually 3 additional parts to setting up pulse.Main AmpsPulse AmpsPulse Time On (width/ balance/ duty cycle)Pulse FrequencyEach one of these have significant effect on how it is set, and what it will do for you.These settings "average" the heat.  There is not exact science to it, as adjusting frequency can do something similar to the heat level as adjusting balance...or adjusting pulse amperage.Don't think about adding or subtracting...it's all about averaging.With all things set equally though and only adjusting one feature at a time:Increasing the pulse time on, will increase the time the unit spends in the low stage cycle of the pulse, thereby making it run a cooler puddle.Decreasing the pulse time on will decrease the time the unit spends in the low stage cycle of the pulse, thereby making it run a hotter puddleIncreasing background/pulse amps (as a percent of welding amps) will increase  the overall heat, by decreasing the differential in amps and raising the average amps.Decreasing background/ pulse amps will decrease the overall heat, be increasing the differential in amps and lowering the average amps.Increasing the Frequency of the pulse will compress the time that both the welding amps and the pulse amps stay in their respective part of the cycle as defined by the pulse width/balance and cause the arc to constrict and focus.  This will decrease the overall heat, but also pinpoint the available heat in a more defined area.Decreasing the Frequency of the pulse will expand the time that both the welding amps and the pulse amps stay in their respective part of cycle as defined by the pulse width/balance and cause the arc to broaden, and spread the head over a wider area, which will extend the heat to a wider weld area.  Depending upon the exact settings of the others, low pulse frequencies offer greater control and freezing of the puddle for manual manipulation.  Higher pulse frequencies over 150 Hz really begin to loose their practicality for manual TIG welding.Esab Migmaster 250Lincoln SA 200Lincoln Ranger 8Smith Oxy Fuel setupEverlast PowerPlasma 80Everlast Power iMIG 160Everlast Power iMIG 205 Everlast Power iMIG 140EEverlast PowerARC 300Everlast PowerARC 140STEverlast PowerTIG 255EXT
Reply:yup, lugweld is absolutely correct.  What distinguishes your scenario is that in one, 90A is the weld-current in one scenario, and in the other 90A is the base (lower) current.  Those are obviously two completely different scenarios because one has 90A on the LOW end, and the other has 90A on the HIGH end.  It makes no sense to compare those two settings----one could be describing the welding of say, exhaust tubing (where 90A is the max), and the other could be welding 1/8" steel plate/whatever where the lowest the current would go is 90A.  Therefore the question of "should i be welding at..... cannot be answered until you actually specifically state what it is that you will be welding.  Just as you said, one causes the average of the heat input to decrease, and the other causes the average of the heat input to increase.  Therefore the natural question to ask you is:  Do you need to increase the average heat input into the weld joint?  Or do you need to decrease it?Last edited by Oscar; 05-23-2014 at 05:55 PM. 1st on WeldingWeb to have a scrolling sig! HTP Invertig 400HTP Invertig 221HTP ProPulse 300HTP ProPulse 200 x2HTP ProPulse 220MTSHTP Inverarc 200TLP HTP Microcut 875SC
Reply:Originally Posted by lugweldWith all things set equally though and only adjusting one feature at a time:Increasing the pulse time on, will increase the time the unit spends in the low stage cycle of the pulse, thereby making it run a cooler puddle.Decreasing the pulse time on will decrease the time the unit spends in the low stage cycle of the pulse, thereby making it run a hotter puddle
Reply:Originally Posted by Oscaryup, lugweld is absolutely correct.  What distinguishes your scenario is that in one, 90A is the weld-current in one scenario, and in the other 90A is the base (lower) current.  Those are obviously two completely different scenarios because one has 90A on the LOW end, and the other has 90A on the HIGH end.  It makes no sense to compare those two settings----one could be describing the welding of say, exhaust tubing (where 90A is the max), and the other could be welding 1/8" steel plate/whatever where the lowest the current would go is 90A.  Therefore the question of "should i be welding at..... cannot be answered until you actually specifically state what it is that you will be welding.  Just as you said, one causes the average of the heat input to decrease, and the other causes the average of the heat input to increase.  Therefore the natural question to ask you is:  Do you need to increase the average heat input into the weld joint?  Or do you need to decrease it?
Reply:welding_kid, my experience with the PWM technology is limited to VFD's and other motor controls some using PLC modules to set the changes in pulse width to obtain the torque curve needed for best performance of the motor/pump experimenting dynamic loads.In that experience I would contrast it to the Miller Dynasty 300 DX control circuit configurations, The Miller Dynasty 300 DX is a fixed square wave control that has only one variable while welding- amplitude or amperage.  I wanted you to have a reference of how that company does the 'pulsed arc'.  First there is no PWM in the Miller scheme, there is no dynamic changes to the 'set' frequency or the set square wave; thus no (dynamic) Modulation so no PWM; its just a square wave generator with variable amplitude. The settings are fixed/set by the operator by setting values on the front panel and the values are, as has been mentioned. Miller labels the Freq as PPS, their term is Pulses Per Second which is the total time to repeat the uniform, not dynamic surge of amperage.  So, unlike PWM in a motor control the "on cycle, up state" is not 'width modulated' during the run time.The next setting is the "Peak t", where the percent of the time interval (PPS in seconds) is "t". In Miller's method of controlling the amperage surges, this percent of the freq/PPS means if the PPS are 1.0 (one pulse per second)  and the Peak t is 50; the amperage will stay at the high value (foot pedal, slider control circuit value) for 1/2 second and revert to the background amperage for the remainder of the time.Slope of this timer's slew rate between high&low is not controllable on this series welder.  I have not put a scope on the output to see how spiked, or square cornered these waves are.  If the output is at 250 PPS regardless of the Peak t I suspect the wave is 'not so square' so I can't remark about the readings that may happen in real welding, just the front panel controls as I adjust them and the effect on my welding bead.The last 'pulser' control is the Background A control. This is percentage of the Main Amperage Value or that which is output during the Peak t interval  If this control is at 50 and the pedal/slider/control circuit is at 100A then the background is 50A.  Like the upper value which is output during the Peak t period, the pedal or slider and the Main A control set this value.There is no dynamic value changes during the welding process except the main amperage controlled by the pedal or slider circuit, so this is not the PWM of motor control where the switching and dynamic Peak t event is modulated to simulate the ideal wave to carry the load of a motor in changing loads.This function on the Miller is simply a variable timer with preset ratio of the square wave's lower amplitude value as a percentage of the Main A control circuit, the only dynamic is the amplitude of the output or weld current. My primary use is to 'over drive' a weld; that is to weld with lots more amperage than I could sustain without the pulse arc control. I set the ratio of background and frequency to suit the weld, then I use 150%-200% or more percent of a 'regular' weld to perform the weld.I weld aluminum, using a semi automatic, cold wire feed TIG gun, more than other metals and I use the PPS at 125 PPS to give more 'upslope wetting' to the AC puddle.  I find that the upslope of the AC current surge 'wets' out the parent metal faster than standard fixed amperage output. So, to increase travel speed, I use the higher PPS to increase 'wetting the leading edge' allowing faster deposit with less duration therefore less contraction from less expansion.I also use the Peak t at 40-60% so that higher amperage is present about half the time while I'm getting 125 surges per second.  Last by limiting the Background A to 40% of the higher Peak t weld amperage; the overall higher heat is very controllable even while welding in 1/8 or 3/16" 5086 at 300 A peak using .035" fill wire and 1/8" or 5/32" tungsten I get good MIG-like travel speeds. Instead lowering the Main A of the weld, you can simply drop the Background A to a lower % of the Main, and the RMS drops while the many bursts of very high voltage can remain well above what would be possible with a fixed amperage control circuit. Since the averaging that was mentioned above is the RMS function of the net BTU introduced to the parent metal; the benefit of the pulsed weld to my TIG work is to burst a very large current into the parent metal with some filler, allowing a much deeper melt by that burst of amperage, then instantly, before the parent metal fails by over heating, the power supplies 'background A' drops back for the remainder of the Freq/PPS duration and then surges again.By adjusting the rates of this process you can benefit from much higher amperage and penetration without suffering the result of that higher current being carried for the entire weld.  By drawing an RMS function of the square wave, you can see Miller's thinking of how to provide these controls just using the three values listed above and the overriding main welding current output as the only variable- while welding.So from a motor control stand point, there is no modulation of the pulse's (intervals, square wave Freq) width during a weld, only the amplitude; which of course raises or lowers the RMS net input of the BTU to the parent metal.By combining the AC Freq control, which narrows the arc cone as the Freq increases, and the PPS at high rates with a relatively low background to control the RMS net amperage input, AC TIG can be done with narrow fast beads, two to three times deeper than 60Hz transformer power supplies and at travel rates faster than I can move my old carcass.I was somewhat confused by some of the terms in the discussion above so I've tried to make sure I didn't use a term without defining it as I was using that word, even it that lead to a longer post.Cheers,Kevin Morin
Reply:Originally Posted by welding_kidyou described pulsing-down, or in other terms, the PWM maps to the low current setting.not really, no matter the freq, 50% PWM means 50%high & 50%low, or 80% PWM means 20%high & 80%low, the total times for each over any given period is exactly the same for any given PWM & frequency. as example 50% PWM at say 10Hz should yield the same heat as 50% PWM at 100Hz, but perhaps due to the arc shape at varying freq the weld is different?thanks for the info.
Reply:Originally Posted by welding_kidwhat does the welding do when say i am at 90%PWM, this will give a 10% pulse "up", etc.
Reply:Originally Posted by lugweldYou are confusing the effect of frequency with pulse width.  It is not the same.  Frequency controls how long the total time of each pulse cycle lasts. Pulse width controls how long each component of the pulse cycle lasts within that single pulse cycle.  Let's say one hertz, means the pulse lasts one second.  IF you have the pulse width (balance) set, at %, the drop in the pulse will last .25 seconds, and the spike in amperage will last .75 seconds.   With the same width setting, but the frequency tuned to 2 hertz, the drop will last for .5 second and the spike in amperage will last for 1.5 seconds.  For those who don't know: Frequency = number of full pulse cycles (low amp stage to high amp stage and back to the beginning of the low) per second= Hz.
Reply:I don't think you understand welding at this point.  Your question is a moot one, because you've excluded other variables.But you don't even understand the basics of what is going on in the pulse.  You are confusing terms and really complicating something that is fairly simple.  Stop over thinking it.  You are letting electronic jargon confuse the situation rather than simplify it.  WHAT controls the visibility of the pulse is the frequency.  You can no more see 100Hz at 10% or 90% than you can see a fluorescent bulb oscillating 60 times a second. It will not look brighter if that is what you are asking...It will at 100Hz, more or less look like a steady stream. But something at 1 hertz, you can see.  Up to about 30 hertz, your eye can differentiate a little, but over that, your eye gradually looses perspective and you can't see it no matter how far the  "half" cyles of the pulse itself is skewed in HIgh versus low amp settings.   If you say otherwise, you are proving you really don't understand it and are ignoring what people have told you.It is harder to teach someone who thinks they know something about welding than a complete noob who walked into a welding booth the first time off the street.  Clear your mind of what you think you know and start over.Last edited by lugweld; 05-24-2014 at 11:08 PM.Esab Migmaster 250Lincoln SA 200Lincoln Ranger 8Smith Oxy Fuel setupEverlast PowerPlasma 80Everlast Power iMIG 160Everlast Power iMIG 205 Everlast Power iMIG 140EEverlast PowerARC 300Everlast PowerARC 140STEverlast PowerTIG 255EXT
Reply:brightness and freq are two totally different things. @100Hz the PWM will determine the "brightness" at the eye. you are missing my point to my original Q.and yes, at the lower freq one can see a quick pulse down or up, say 3Hz @ 10% PWM, it looks like a blip. 50% it looks even. my 100Hz example was a tad off, i understand that 100Hz is a tad too fast for the eye.......... the example was to say pulsing "up" vs "down", etc.can anyone show some tig beads w/o filler say at 50Hz @ 10%PWM and then again @ 90%PWM, say on 1/4" steel with low amps @50 and high amps @100.and btw, i have been welding for almost 20yrs.Last edited by welding_kid; 05-27-2014 at 12:51 AM.
Reply:hey lugweld,do you have any pics of pulsing with TIG, say w/o filler just to show what the pulses do, maybe 6 welding settings, 10/50/90% @10Hz, and then 10/50/90% @100Hz. i suspect with all your welding experience you might have some readily available?
Reply:Most  I know of don't stop to take pictures of their welds unless there is a specific point to it.  I am one of those.  I prefer taking pictures of the completed project.   But I think what you might like to see is one of the first welding videos Jody of weldingtipsandtricks.com did several years ago with pulse as he was getting wrapped around the concept.Here is the first part (part 4) where he begins to discuss TIG pulse.  Look for the other links (part 5 and 6). He also deals later with practical applications in some videos.  I think this does about as good of job demonstrating what you are wanting to know as anything out there, and done in a controlled environment to take out any "human" factor.  He explains each adjustment on the effect on the weld.Esab Migmaster 250Lincoln SA 200Lincoln Ranger 8Smith Oxy Fuel setupEverlast PowerPlasma 80Everlast Power iMIG 160Everlast Power iMIG 205 Everlast Power iMIG 140EEverlast PowerARC 300Everlast PowerARC 140STEverlast PowerTIG 255EXT
Reply:that's Jodi's videos. i saw those moons ago. but i dont see him making the adjustments across 10-90% PWM using the gamut of freq's.but hey, thanks for posting it.and then look at the machine freq knob, it goes to 500Hz ???? wasnt there a post in this thread that says anything above 150Hz is kinda useless? if so then why does his machine go to 500Hz?he also says the pulse % is how much time it runs on the "high" side, thus his %PWM is mapped to the high side current (his max current setting). thus, his 51-90% PWM will run more time on the high side than low side, and his 10-49% will run more time on the low side than high side.he doesnt show anything with changing the %PWM, he only changes the 1st two knobs. my guess is he made video using 50%PWMLast edited by welding_kid; 05-29-2014 at 02:53 PM.Again, watch the other videos as he covers it.  Also read the information on his site under TIG pulse.  As you see, the unit does go up to 500 hz, but it is more difficult to take advantage of manually...as you see he is on a steady machine.  The greatest benefit is achieved  manually with the most dramatic effect is with 0-150 hertz .  http://www.weldingtipsandtricks.com/...ent-pulse.htmlEsab Migmaster 250Lincoln SA 200Lincoln Ranger 8Smith Oxy Fuel setupEverlast PowerPlasma 80Everlast Power iMIG 160Everlast Power iMIG 205 Everlast Power iMIG 140EEverlast PowerARC 300Everlast PowerARC 140STEverlast PowerTIG 255EXT
Reply:[QUOTE=Kevin Morin;4212981]welding_kid, my experience with the PWM technology is limited to VFD's and other motor controls some using PLC modules to set the changes in pulse width to obtain the torque curve needed for best performance of the motor/pump experimenting dynamic loads.Kevin,Thanks for the best, easiest description of Miller technology I have seen.Jerry30+ yrs Army Infantry & Field Artillery, 25 yrs agoMiller 350LX Tig Runner TA 210, spool gunLincoln 250/250 IdealArcESAB PCM 500i PlasmaKazoo 30"  vert BSKazoo 9x16 horiz BSClausing 12x24 lathe20T Air Press
Reply:Storeman, glad it helped.Cheers,Kevin MorinKenai, AK
Reply:Any progress with this?L-tec Heliarc 306Miller 210Victor O/A rig
Reply:Originally Posted by arqangel67Any progress with this?
Reply:Originally Posted by arqangel67Some very good info in this thread. I am new to pulsing and have not had very much experience with it.
Reply:Originally Posted by docweldergood 411 for sure although every-time i think i'm starting to understand the concept behind pulse along come all these other terms like pulse balance,width, time, ect- ect. i'm new to tig and the bells and whistles that come with it are making my head spin. and now pulse up and down. wtf?!
Reply:Originally Posted by docweldergood 411 for sure although every-time i think i'm starting to understand the concept behind pulse along come all these other terms like pulse balance,width, time, ect- ect. i'm new to tig and the bells and whistles that come with it are making my head spin. and now pulse up and down. wtf?!
Reply:Originally Posted by docweldergood 411 for sure although every-time i think i'm starting to understand the concept behind pulse along come all these other terms like pulse balance,width, time, ect- ect. i'm new to tig and the bells and whistles that come with it are making my head spin. and now pulse up and down. wtf?!
Reply:i think i'm starting to get it. as for high school physics, that ship has sailed too long ago and i'm lucky if i can to do long division. my ta 186 didn't come with a foot pedal. i ordered one and it should be here today so between this and other thread's plus jody's t&t's i have a good start.i.u.o.e. # 15queens, ny and sunny fla
Reply:I'll add a comment relative to the question of high frequency.  I've heard the comment about frequencies greater than 150Hz being useless.  I think this is probably true for manual welding.  BUT those miller power supplies that are capable of even higher frequencies, up to 500 Hz, might have applications for mechanized TIG welding.  A person can move at travel speeds below; perhaps 10 inches per minute.  I don't think anyone can TIG weld and control filler metal additions, torch angles, and direction of travel when moving at speeds greater than about 10 inches per minute.But a machine can move and react much faster.  Maybe Someone with more experience with hot- or cold-wire orbital TIG for pipe welding; or some other mechanized TIG welding rig, could comment.  But I would hazard a guess that at high travel speeds, the higher pulse frequencies are useful.  If the weld pulsing were being used to control wetting of the puddle, bead size, or ripple shape, then at high travel speeds a high pulse frequency might be needed.Benson's Mobile Welding - Dayton, OH metro area - AWS Certified Welding Inspector
Reply:the welding trade has added terms like "background" and "pulse" to pulsing. its nothing more than PWM of the electrons flow coming out of the device. PWM is nothing more than duty cycle & frequency (albeit freq is technically independent from duty cycle). what amps are at high and low are variables, and what you call the "pulse" can be the high side or low side of the current.the std nomenclature for "pulse" in PWM is tied to the high side as shown in this pic.Last edited by welding_kid; 07-09-2014 at 10:12 AM.
Reply:Originally Posted by welding_kidthe welding trade has added terms like "background" and "pulse" to pulsing. its nothing more than PWM of the electrons flow coming out of the device. PWM is nothing more than duty cycle & frequency (albeit freq is technically independent from duty cycle). what amps are at high and low are variables, and what you call the "pulse" can be the high side or low side of the current.the std nomenclature for "pulse" in PWM is tied to the high side as shown in this pic.
Reply:Originally Posted by A_DAB_will_doI'll add a comment relative to the question of high frequency.  I've heard the comment about frequencies greater than 150Hz being useless.  I think this is probably true for manual welding.  BUT those miller power supplies that are capable of even higher frequencies, up to 500 Hz, might have applications for mechanized TIG welding . . . (snip) . . .I would hazard a guess that at high travel speeds, the higher pulse frequencies are useful.  If the weld pulsing were being used to control wetting of the puddle, bead size, or ripple shape, then at high travel speeds a high pulse frequency might be needed.
Reply:Originally Posted by Kevin Morinwelding_kid: First there is no PWM in the Miller scheme, there is no dynamic changes to the 'set' frequency or the set square wave; thus no (dynamic) Modulation so no PWM; its just a square wave generator with variable amplitude. Cheers,Kevin Morin
Reply:Originally Posted by 4sfedHowever, the electrical engineers that designed the machines have decided to use terms more descriptive of the welding process, and apparently the welding engineers have found that varying current (via the pedal) is more useful to the process than changing the width of the pulse . . . so let's not argue the definition of pulse for this discussion.
Reply:Originally Posted by Kevin Morinwelding_kid: First there is no PWM in the Miller scheme, there is no dynamic changes to the 'set' frequency or the set square wave; thus no (dynamic) Modulation so no PWM; its just a square wave generator with variable amplitude.Cheers,Kevin Morin
Reply:welding_kid, you've posted a NON-PWM diagram! There is no modulation (Dynamic Change) in any of the diagrams!  Each line shows an instance of one single period- hence- by the definition in English- and all control language: there is NO (none, nada, zero, null set, not any) Modulation of the period/pulse's "width".https://en.wikipedia.org/wiki/Modulation  the concept in this word is change- not fixed or set values. (am I missing something?)Your diagrams do not illustrate Pulse Width Modulation; your post of diagrams all illustrate Fixed Width Pulses.https://en.wikipedia.org/wiki/Pulse-width_modulation, here is a little diagram showing a modulating, (ie. =changing 'width) and note that you've posted FIXED width pulses? I'm not sure if you're being serious?  Is this just some spam and troll routine you have to run on folks here?A pulse is only width modulated when there is a change in the period/pulse-width DURING the continuous operation of the device subject to that control method: your use of terms is so illogical as to appear intentionally disruptive?Is this just a late April Fools? Could you take time to remark why are all the words you use so off-point and outside accepted wave form terminology definitions?  Is English your second language?  (If so, I apologize that I'm being impatient with your demonstrable ignorance of English language technical terms.)If you're being serious, then why to you keep ignoring the others' clearly uniform use of terminology and continue with your Laurel and Hardie inspired "Who's on First?" routine?You have not demonstrated any knowledge of the terminology used for welding circuit controls, nor for that matter industrial controls overall, why did you ask the question if you won't accept the information correcting your erroneous understandings?sort of confused by the thread.Cheers,Kevin MorinKenai, AK
Reply:Originally Posted by welding_kidyikes, if its a square wave then it inherently has duty cycle and frequency = PWM, no way around it. not adjustable is a Miller flaw.
Reply:Originally Posted by Kevin MorinWell for the others that statement clearly shows you're not using the same definitions.  Duty cycle and frequency are not equal to PWM, by the electronic definition of the words.Pulse- some regulated shift in a fixed output value; thereby creating an amplitude or wave form instead of fixed output DC/ACWidth- a period (of time) of the wave form, a fixed value unless there is a real time modulation of this value.Modulation- change in value of a wave form's properties while the wave form is being used to do work. (comm/power/weld)[It does appear you're able to grasp that the pedal/pot/remote amperage circuit is able to modulate the amperage peak value? But the ratio of max amperage to background or low cycle amperage is not adjustable while welding, just the peak value the background ratio, exactly like the fixed period is not adjustable while welding, so both the period/pulse width, and the amplitude variation is only set/adjusted/manipulated between welds.]Of course the Miller Power supplies do provide all the wave form controls needed to changed any fixed wave form properties, between welds, as you'd have realized if you'd read what was posted above.  What is not done in the Miller, or any other power supply that I'm aware, or has been posted here; is to change the period/pulse width while welding: Nope! not a single Pulse Width Modulating welding power supply on earth.Wave form controls that do not change the Pulse's Width while welding are not PWM- by definition. " yikes! "   Yes a way and a long, long way around your failure to use the language as it is defined for the 'rest of us'. But sail on, you don't have to be bothered by that kind of limit; just make up your own terms and have it, clearly you have to this point, why stop your fun and silliness now?Cheers,Kevin Morin
Reply:Originally Posted by welding_kidyikes again, my old farty esab 161 changes frequency when i am in AC mode and i step on the pedal. thus, when i step on the pedal i am changing amperage and frequency.
Reply:SqWave 200Millermatic 190Airco 200 ACHypertherm PM45Boice-Crane Band SawVictor O/A
Reply:i am still not sure why this is hard to understand."Pulse-width modulation (PWM) is a modulation technique that controls the width of the pulse."whats so hard to understand "WIDTH OF PULSE". the width of pulse is directly related to frequency and DUTY CYCLE %, which in std nomenclature is a % on the high side. the PWM does not need to vary (but it can in fancy modulation schemes), in welding machines the PWM (freq, duty cycle, max amps, min amps) is usually fixed by a user turning some knobs or set in a program used in automation (aka, "the technique that controls"), and then welds. if you are concerned about "modulation" meaning the changing of the signal, then in fact the electrons flow is changing, its not one set current 100% of the time.and yes, sorry, some machines have dynamic freq change when using the pedal. to be more accurate though, on my machine when on AC TIG the freq is based on amps and not pedal position. i can AC weld w/o pedal and when i twist the current knob the freq will change, but when on pedal the freq changes down as i add more amps. sorry that you didnt know some machines do this. not sure why you are looking for manual, i am telling you this is what my machine does.did you read the manual??Code:The AC frequency is not locked to main frequencysee http://edgewh.esabna.com/literature/...e_15-655-E.pdfand as i mentioned earlier, PWM (fixed or varying) has at minimum two components, duty cycle (related to "pulse width") and frequency. when freq=0 the signal is not varying.and yes, some will say "pulse width is the actual time during high side of pulse", very true, but "duty cycle" is a better way to relate the items together because it decouples frequency, thus 50%duty is half on half off no matter what frequency, and, the actual time used in pulse width can be derived from frequency and duty cycle.Last edited by welding_kid; 07-10-2014 at 10:12 AM.
Reply:Originally Posted by welding_kidand as i mentioned earlier, PWM (fixed or varying) has at minimum two components, duty cycle (aka "pulse width") and frequency. when freq=0 the signal is not varying.and yes, some will say "pulse width is the actual time during high side of pulse", very true, but "duty cycle" is a better way to relate the items together because it decouples frequency, thus 50%duty is half on half off no matter what frequency, and, the actual time used in pulse width can be derived from frequency and duty cycle.
Reply:Originally Posted by MinnesotaDaveI'll take a shot at this discussion...Why are you not framing your terms the same as the welding manufacturers?  Seems I missed something.All of the terms you use likely make perfect sense when working with electronics, but deviating from normed welding industry terms while discussing tig pulse for welding just serves to confuse the issue.