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Up Topic Welding Industry / Technical Discussions / Electrical guru's feel free to take a stab at this one.
- - By Kix (****) Date 12-10-2007 16:08
   I've got a welder that is telling me the wire I've told him to run is junk.  He says it runs like crap, but I haven't had any complaints from anyone else.  I went to investigate the problem without a welding hood so I did not get to jump under the hood to see what was going on.  I did however hear something suspicious.  He is welding with a Miller Deltaweld 452 CV-DC power source and a Miller 60 series dual feeder.  The mode of transfer is spray.  While he was welding I could here a slight hum in the arc almost like it was in spray pulse, but this machine does not have this feature.  It sounded like a 60Hz hum if that means anything to anyone.  I'm thinking the machine is getting sick. Thoughts anyone? 

  Thanks, Ray C.
Parent - - By MDG Custom Weld (***) Date 12-10-2007 16:19
Ray,
Maybe you are right on your thoughts of the power supply. 
Is it maybe a feeding problem where the wire is intermittently slowing down and causing a long arc so you can really hear the arc humming?  Also, is there any tig welding going on at the same time on the same part or table?  We had a problem with a 60 feeder that was touching a table where someone was tig welding and the 60 feeder was going haywire from the high freq.  We moved the table and all of the problems went away.
Mark
Parent - - By Kix (****) Date 12-10-2007 17:01
I think it's something to do with the 3 phase screwing up.  Feeding is not an issue and there is no tig welding in the area.  This particular machine is totally isolated.  I'm in the process of hooking up a new machine to the same power supply off the wall so we'll see what happens. 
Parent - - By ssbn727 (*****) Date 12-11-2007 03:53 Edited 12-11-2007 04:04
Do you have power factor correction in your Deltaweld power source? I ask this because if one of the capacitor cans are leaking just a bit, they could be the cause... If I were you, I would first check the each leg of your 3 phase power supply, then check for proper phase rotation... If you're not a properly licensed electrician or a properly trained electrical technician, do yourself a favor NOT to mess with 3 phase circuits!

The other thought pertains to a feeding problem that could be the result of your spool tension being out of whack - causing the wire to resist from feeding properly into the drive roll mechanism or, the spool is'nt properly seated on the spool holder or, the drive rolls are not aligned properly or you have a smaller diameter wire being used than called for according to the orifice diameters presently found in different locations where the wire is being fed through... Another possibility is the type of contact tip, and it's position in relation to the gas cup??? In other words, make sure all of the components are adjusted properly on the wire feeder with the spool & wire before you start looking towards the power source to be the cause of the problem.
all the Best to you & Happy Holidays!!! :) :) :)

Respectfully,
Henry
Parent - - By PlanB (*) Date 12-11-2007 04:38
I would'nt think it was a incoming power problem. Rotation should not matter on a welder. As long as phase inbalance is not more than 3.5 %, should not be a problem. Dont have the standards in front of me. And if you are checking voltage, do it at the sorce with load on it. Do you have any moe info? Keep us informed. Thanks Troy
Parent - - By DaveBoyer (*****) Date 12-11-2007 05:21
Things I would check are: Voltage and amperage draw of each phase on the incoming power while the guy is welding. Obvious signs of capacitor problems, primary and secondairy circuts. Obvious rectifier/SCR/transistor problems. The obvious problems would be oil leaking from caps, signs of overheating or arcing on the tops of the caps and rectifiers/SCRs?transistors. Failures in any of these items would effectively pulse the output at 60hz. If the voltage is within reason on all the phases but the amperage varries greatly, obviously there is something wrong, You just need to find it.
Parent - - By darren (***) Date 12-11-2007 11:59
it may not be very technical but from my experience as a welder when a machine starts to make a hum through the arc and its not a pulse machine.
"its done shit the bed" she needs a trip to the welder doc
just my 2 bits
darren
Parent - - By Kix (****) Date 12-11-2007 13:34
Well, Darren I think I would definitely agree with you and Dave I think you hit the nail on the head.  I got my man a new power source and it's running sweet as can be.  Now I have to convince maintenance that there is something wrong with the old one.  They will get the machine in the shop and try to weld with it and tell me "it welds what's wrong with it".  Thanks for the excellent advice you guys! I had a hunch that it was something to do with the way the machine was rectifying the 3phase A/C input when I heard that 60Hz hum.  I'm not real familiar with the internals of a welding machine and how it all works unfortunately, but I'm learning from you guys!!!
Parent - - By ssbn727 (*****) Date 12-11-2007 15:32 Edited 12-11-2007 16:29
Just out of curiosity, I looked at the owner's manual for the Miller Deltaweld 452, and I noticed in the troubleshooting section on page 27 (.pdf page 31 of 36) that reads a symptom such as: "Erratic or improper weld output" there are 4 choices to look towards, and they are listed as:
1) "Use proper size and type of weld cable (see section 4-8.)
2) "Clean and tighten all weld connections."
3) "Check wire feeder installation according to owner's manual."
4) "Have Factory Authorized Service Agent check control board PC1 and/or SCR in Main Rectifier

Miller Deltaweld452 owner's manual:
http://www.millerwelds.com/om/o223aq_mil.pdf

I then decided to look at the schematic, and it sure does make sense that the fourth possibility may be the cause as to why this humming is occurring and your arc characteristics are erratic.

The only other possibility that could be causing this is if the power source has a line voltage compensation circuit (a type of Power factor correction) and it's not working properly. However, this is only a remote possibility if all else fails in the troubleshooting process.

Finally, if you have one of the welding cables connected to one of the two positive connections, (Low and High stabilizer) if one looks and interprets the schematic in the owner's manual, one will notice that both of them are connected to what looks like a "hall effect" transformer? A couple of resistors, and what looks like some capacitors. In other words, check to see if R3, (R7 optional if present) HD1, Z1, CR6, and both C4 & C2 are operating properly. Also check the components on the Negative output circuit such as R6, and C1.

However, I would first and foremost, eliminate any of the other possibilities before getting the power source serviced in order to avoid any unecessary service call that ends up diagnosing the problem's root cause as being any one of the first three possibilities because, a Factory Authorized Service Call can be expensive if the power source is out of warranty, and embarrassing if the problem turns out to be something one could have fixed themselves. In any event, good luck, and I hope it's an SCR instead of a PC motherboard if the power source is out of warranty!!!

Hey Maybe it's one of those smaller, less complex components that are part of your positive, and negative output circuits past the SCR's and Motherboard on the "schemo" :) :) :)

Respectfully,
Henry
Parent - - By Kix (****) Date 12-11-2007 16:54
Hey thanks Henry!! Thats some good info to have in the ol bag of tricks!!!
Parent - - By 357max (***) Date 12-12-2007 03:09
BTW the Deltaweld is a 3 phase ac input/dc weld output. Power factor correction only applies to single phase ac input w/ac (smaw & gtaw) weld output. Its major function is to reduce the primary amp draw.
Line voltage compensation can be found on single or 3 phase input machines & is found on most machines with solid state components and that donut looking "hall" device on the output cable.
Parent - - By ssbn727 (*****) Date 12-12-2007 02:22
Remarkable! It's been awhile since I used to be a factory authorized service tech for Miller back in the eighties but as far as power factor correction is concerned, when I made my first post, I did'nt even look at the manual, and was only going from my memory which is'nt the best way to go so, I did'nt even know if it was included with the deltawelds 452's...

I do know that back in the day, one could order PFC (Power Factor Correction) with the 3 phase units because, I personally installed twenty of the then Miller delta weld 600's, and thirty-two Miller Intelliweld's@ the old GM assembly plant in North Tarrytown, NY!!! I even rebuilt two transformers, and changed many a motherboard, SCR's, hall devices, added Capacitors, PFC banks, and many other components due to how terribly they protected those power sources from hi freq coming from other sources, and yet they did'nt do anything to prevent the hi freq from infiltrating the equipment!!! Go figure!!!

The result would be a disruption of the internal harmonics from an outside source combined with then unconditioned 3 phase primary input power lacking a VAR automatic switching capacitor circuitry for "Active"
PFC as opposed to what we ended up doing as a less efficient solution which was to install "active" PFC for each power source... Talk about Capital Equipment Tax write offs!!!!

Power Factor Correction can be used, and is commonly used in the form of active type power factor correction with localized 3 phase power sources such as a Miller deltaweld 600 or the Deltaweld 452 if ordered as an option from Miller but, it does'nt come standard. Single phase power sources usually use a form of "Passive" PFC which normally consists fo a bank of capacitors and resistors for filtering which will only compensate current fluctuations and are used primarily with single phase primary input.

Power Factor Correction compensates current fluctuations that were notorious (less than a factor of one) in certain parts of NY state and especially in the greater NYC metro area.
here's wikipedia's explanation in order to clarify what 357max meant:
http://en.wikipedia.org/wiki/Power_factor_correction
Here's more to read on PFC:
http://www.ibiblio.org/obp/electricCircuits/AC/AC_11.html#xtocid88953
http://www1.eere.energy.gov/industry/bestpractices/pdfs/mc60405.pdf
http://www.onsemi.com/pub/Collateral/HBD853-D.PDF
http://freeenergynews.com/Directory/PowerFactorCorrection/index.html
http://www.dansdata.com/gz028.htm
http://www.fairchildsemi.com/an/AN/AN-42047.pdf
http://www.endpcnoise.com/cgi-bin/e/pfc.html

LineVoltage Compensation is sort of another form of power factor correction that compensates for fluctuations in line voltage which makes it different than normal known Power Factor Correction circuits. Nonetheless, if your line voltage is'nt compensated in a sufficient amount of time, your power factor can become less than one which would then require one to have PFC in the first place... This can be achieved by installing what is known as a an "Active" Power Factor Correction circuit.

Having both types of circuits installed locally such as part of the power source itself is extremely beneficial in locations throughout the country where there are known conditions whereby at certain times of the workday, both Line Voltage Compensation, and Power Factor Correction or better known as "Active" PFC is required, and must be installed locally in order to keep the factories, and shops humming like a symphony as opposed to sounding like having the harmonics of a Heavy Metal Rock band due to the fluctuations of Line voltage, and current changes. The power companies use both as the customers locate further, and further from the substations.

So I respectfully disagree that power factor correction is only limited to single phase power sources because, it all depends on what type of PFC is being used which for single phase usually means a passive form of PFC.

Respectfully,
Henry... You know - like the unit of electrical measurement!!! :) :) :)
Parent - - By 357max (***) Date 12-14-2007 20:25
BTW ..."When ac voltage and current are in phase, the power factor is said to be unity or 1; thus with unity power factor, kilowatts (kW) equals kilovolt-amperes (kVA).
The power factor of an industrial user company is rarely unity, however, since most electrical equipment in a factory generally consists of motors that tend to cause the volts and amperes to become out of phase. A single phase ac transformer welding machine has an inductive electrical load. This causes the current curve of the alternating cycle to lag the voltage curve by a number of degrees. This creates lagging power factor. The electrical utility company monitors industrial customers and establishes a power factor for the company. This is entered into a formula so that the factory will pay a penalty when the power factor is less than unity. The power factor of an industrial plant can be improved or moved toward unity by correction devices such as power factor-correcting capacitors. In the case of a single-phase transformer welding machine, a power factor-correcting capacitor can be built into the machine to provide a correction factor, bringing the power factor close to unity, and is normally recommended." Modern Welding Technology fifth edition Howard B. Cary.
Miller's catalogue shows the Dialarc 250P AC/DC, and Syncrowave 250 & 350 as having power factor correction or as a field installed option. The Deltawelds do not have it as an option. There are lots of their machines that have line voltage compensation as standard and not as an option. The Syncrowave 250 & 350 have as standard, line voltage compensation (..."compensates for power fluctuation without changing your welding parameters. Line Voltage Compensation works on fluctuating power + / - 10%" ) and as a field installed option the power factor correction. ..."Reduces primary amperage draw by approximately 25% allowing the use of smaller breakers/fuses and smaller primary cord. Power Factor does not reduce the power consumption/electrical bill." Miller's Syncrowave literature sheet.
It's possible that solid state contactors were installed in deltawelds in the 80s to replace the electro/magnetic contactor switches.
Parent - - By DaveBoyer (*****) Date 12-15-2007 06:13
I don't understand Miller's statment that power factor doesn't affect the electric bill, unless it has something to do with how the meeter reads the power usage. With power factor corection the rated load amperage does go down, but the idle current goes up quite a bit. My 360 A B/P draws 40 amps idling, and 30amps while welding with a 1/8" rod. If I was going to use this machine for stick welding I would unhook the power factor corection caps.
Parent - - By 357max (***) Date 12-19-2007 16:44
We pay the electric utility for the kiloWatts used. Power Factor Correction Capacitors changes the kW used very little. It is the penalty charges that the electric utility levies on users because of poor power factor. And the penalty may be about 5-7 cents plus the regular 8-11 cents kW charge in some areas. It is levied on the entire electrical use or bill. Not just for a particular machine's usage. So unhooking the Power Factor Correction Capacitors will not decrease the electrical consumption. The idle current is used to charge the capacitors.
During the 50's & early 60's AC "buzz" boxes were sold with the Power Factor Correction for farm and ranch use. These users were REA (REC) Rural Electric single phase 208 or 240 VAC consumers. And to provide a stable utility power to each and every location "on the line"; REA required Power Factor Correction on the welding machines. You may notice the need for Power Factor Correction if an AC arc is struck and the lights go dim in your garage.
Power Factor Capacitors may be used on ac transformers or transformer rectifier welding machines. Wikipedia - "Power Factor Correction attempts to adjust the power factor of an AC load (ie. AC weld output)..."
Line Voltage Compensation is found on Solid State (printed circuit boards) Controlled welding machines. Line Voltage Compensation compensates for fluctuating primary line voltage. Power Factor Capacitors may be added to AC weld output single phase solid state controlled machines.
Parent - By DaveBoyer (*****) Date 12-20-2007 06:55
357: The PF caps do make the idle current go up considerably on the Miller 360 A B/P. This is not a buz box, it is a 600 amp transformer rectifier. In the tig mode there is no appreciable idle time, as the primary contactor is closed and an arc is initiated. When used as a stick machine the contactor stays closed and the 40 amp idle current keeps the electric meeter spinning. At rated load machines of this type draw about 25% less amperage when they have the PF caps, as You mentioned in Your earlier post. There is some point where the tradeoff would actually save KWH of power usage, but I can tell You I don't see the day coming where I use this machine above 50% of rated power. I had a friends Dialarc 250 HF in the shop years ago. It did not have the PF caps. It worked fine in spite of probably throwing the power factor of Our rual service out of wack. Line voltage compensation is a newer invention than any of the machines in My shop.
Parent - - By ssbn727 (*****) Date 12-16-2007 09:36 Edited 12-16-2007 09:38
I don't know about you but, any customer can "special order" what they want from Miller, Lincoln, ESAB (In the eighties the company was Linde/Union Carbide/LTec before being bought out by ESAB) so long as they pay a premium for it without having the feature listed in the company catalogue as an option especially if they purchase the equipment direct!!! The deltawelds were designed differently back then as were the "intelliwelds" also!!

The current power sources are much more efficient today than back then so please, do'nt even try to compare! besides, Miller does'nt own the power factor correction market, and is not exclusive to, welding power sources so, before you start referencing Miller electric with quotes that do NOT make sense to the topic at hand, get your facts straight!!

No disrespect to the late, great Howard B. Cary but, he was'nt an electrical engineer!!!
Now I do'nt know about you but I did go to Miller electric's welding equipment repairperson's factory authorized warranty repair course in 1983, and I "aced" that course!!! I also did more repairs in the field than most other service techs because I knew how to cut through the BS and properly troubleshoot, and diagnose problems in not only Miller but, all major brands of welding and cutting equipment in the Greater New York, New Jersey,Long Island, Conn. metro area . So I know my way around electro-mechanical, and solid state electronics for quite some time!!!

I'm very familiar with PFC & LVC in welding power sources!!! I mean, did you even bother to read any of my own post or are you someone that only reads bits, and pieces and suddenly shout to themselves "THAT'S WRONG!" then posts a reply that does'nt make sense? Go back and read some of the websites I posted in my previous reply, then show me some respect son!!

Respectfully,
Henry
Parent - - By 357max (***) Date 12-18-2007 15:12
Having not heard of, nor seeing the explanation for three phase arc welding machine's need for a Power Factor Correction in your post about a Miller Deltaweld. I respectfully question if the power factor capacitors you reference is the Output Filter Capacitors. Which when they fail produce a single phase arc. And possibly the funny arc sound Kix is querying about. Checking early '80s Deltaweld Tech Manuals shows no reference to Power Factor Correction Capacitors (standard or option), only the Output Filter Capacitors. The '80s Deltawelds internally, schematically look alot like today's machines. I might have missed something in my early 90's Miller's Service Tech program but I do remember the "Single Phase" failed Output Filter Capacitor troubleshooting bug they put in the Deltaweld.
I have installed a number of Power Factor Correction field kits in the single phase Syncrowaves though. This Power Factor Correction for ac weld output's application on single phase arc welding machines I understand. Power Factor Correction for electric motors I understand. On three phase transformer rectifier arc welding machines; I don't. Please explain.
Parent - By DaveBoyer (*****) Date 12-19-2007 03:57
Max, I can't give the explanation You want because I only understand this stuff half assed Myself, BUT: It seems there is something inherently less efficient in a transformer power suply with a drooping volt amper curve when compaired to a CV unit. Amperage draw on a single phase power suply of a given output is high because all of the power is coming from 1 phase. The combination of these makes a single phase CC unit the worst case for power factor problems, and I suspect the reason these units have PF corection available. The 3 phase transformer is an inductive load, so to My limited understanding won't have a unity power factor. PF capacitor banks are at times placed on the electrical service in industrial plants to compensate for the lack of PF corection in the equipment being powered. As You point out the schematic for that Deltaweld doesn't show any caps on the primary side.
Up Topic Welding Industry / Technical Discussions / Electrical guru's feel free to take a stab at this one.

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