SAE-400 rated duty cycle. Why so low?

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Was just looking at the online operators manual for the SAE-400.  It says the duty cycle is rated at 60% at 400 amps. huh? So basically if I wanted to air arc I cant even use 1/4 carbons without worrying about over heating this big a$$ machine?
Reply:SA 200's have a 60% duty cycle, too. I've welded 15-18 hrs. straight thru, breaking to change rods and an occasional smoke, 7 days a week for weeks at a time and I've never burned one up. I have to admit I used them very little with an Air Arc, tho.
Reply:All Commercial duty ratings on those older machines and many new ones have a rating at either 50 percent or 60 percent duty cycle.  That doesn't mean that at some amperage,usually at only a slightly lower setting, it won't perform at 100 percent duty cycle.  This is absolutely normal.  It allows for changing rods, chipping and readjustment.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 machine should do well with 3/8" carbons. I've heard people worry over that 60% rating for years. The older machines were underrated.The thing is, what kind of duty cycle do you realistically think you need?  If you are gouging, you will need to stop and change positions, move the carbon in the holder, clean up, etc.
Reply:[QUOTE=J Hall;258746]That machine should do well with 3/8" carbons. I've heard people worry over that 60% rating for years. The older machines were underrated.The thing is, what kind of duty cycle do you realistically think you need?  If you are gouging, you will need to stop and change positions, move the carbon in the holder, clean up, etc...................................................  ..................................................  ....................................................................................  ..................................................  ..................................Some of you might NOT understand a "duty cycle".60% means 6 minutes( at 400 amps )  out of each 10 minute time period. Or, you could use 60% of 400 amps , continuously. (or 240 amps. ) For 2or 3 minutes ,( out of each 10 ) you could use maybe 500 amps .[SIZE="5"Yardbird"
Reply:It's safe to say that 60% duty cycle rating wasn't just pulled out of the air my the manufacturers based on the observations stated above thus far.MM200 w/Spoolmatic 1Syncrowave 180SDBobcat 225G Plus - LP/NGMUTT Suitcase WirefeederWC-1S/Spoolmatic 1HF-251D-1PakMaster 100XL '68 Red Face Code #6633 projectStar Jet 21-110Save Second Base!
Reply:Roy, Close but not quite on the duty-cycle.If the machine's duty-cycle is listed as 60% at 400 amps, it does mean that it is rated to run for 6 minutes out of 10 minutes at 400 amps and then is supposed to idle or cool of for the other 4 minutes (out of 10 minutes).And yes, you're right that running at higher amperages shortens the duty-cycle.But the duty-cycle rating on most machines is NOT linear, and the 100% duty-cycle rating is typically NOT arrived at by multiplying the duty-cycle percentage times the amperage at  that duty-cycle to get the 100% duty-cycle.Example: Invertec V205S has a listed duty-cycle of 60% at 190 amps 27.6V (single pahse input power), and a rating of 35% at 230amps at 29V, and a rating of 100% at 155 amps at 26.2V.For the SAE400 with the Perkins diesel engine (Code number 10137 and manual IM-266), the 100% duty-cycle rating is listed as 80% of the nameplate rating.  So that SAE400 is rated at 100% duty-cycle at 320 amps.  The best laid schemes ... Gang oft agley ...
Reply:My main message was to reassure him (Tye's Welding) that he had no worries air-arcing with an appropriate size carbon, if he  used a suitable, safe duty cycle. I used to do (light) air-arcing  with  my SA250 diesel with a 3/16 carbon . to be safe i used max voltage , but one step below max amps. no trouble .[SIZE="5"Yardbird"
Reply:I run 1/4" carbons on my SA-200 and my SA-250 all the time, you ain't gonna hurt that big old mule.Disclaimer; "I am just an a$$hole welder, don't take it personally ."
Reply:3/8 carbons. Look at the gauges. The Amp gauge reads right on 500 amps. The 400 can handle an Airarc. Attached Images
Reply:Nice shots J Hall.  Look like custom add-on gauges.MM200 w/Spoolmatic 1Syncrowave 180SDBobcat 225G Plus - LP/NGMUTT Suitcase WirefeederWC-1S/Spoolmatic 1HF-251D-1PakMaster 100XL '68 Red Face Code #6633 projectStar Jet 21-110Save Second Base!
Reply:They replaced the original gauges, which were $$$$$$
Reply:if anyone is interested, arcair told me one time, that to use any of their rods for gouging, or scarfing, you take the maximum amps the machine will safely supply, inotherwords, this sae 400 which would be in the range of 575 amps, DEDUCT take away 100 amps from maximum, and use the correct size rod for the amperage your using 400-450 amps. for tyes machine, the size would be 1/4" or 5/16" rods.this, what i just said above comes straight from the horses mouth (arcair), because I went through the samething last year, with my 300D perkins. I can SAFELY run 3/16 @ 250 amps, 100 amps less for my machine is 350 amps max. airair also warned that using these engine drives, at maximum amperage, WILLburn up the bearings in a very short time. thermal load.
Reply:I am bad I see,1/2 arcair with 2/o cables,throw quick connectors in 5 gallon pails of water,sae400 perkins,almost got engine temp to 185 on hot day,have a set of 4/o cables also,ground clamp burns off once in a while,it has an oversize bearing in the shaft
Reply:I saw some posts on the AWS site some time ago, and Kaye Sellon of Bill Welder repair said you should absolutely not aire arc with and SA 200. To me they have the power to do light air arc but there must be a reason she is against it. They do work on a lot of machines. Anybody know why you can or cannot. I would like too but after reading that I haven't tried it."Si Vis Pacem Para Bellum"Lincoln Idealarc 250 AC/DCMillermatic 251   Syncrowave 300   30A spoolgunLincoln MP210Hypertherm 45(2) LN 25(2) Lincoln Weldanpower 225 CV(4) SA200   1 short hood    SA250    SAM 400
Reply:Originally Posted by mike r". . .comes straight from the horses mouth (arcair),. . ."  ". . .airair also warned that using these engine drives, at maximum amperage, WILL burn up the bearings in a very short time. thermal load.
Reply:On the surface, the  bearing damage issue may not seem to make sense, but, there may be something to this. If you've ever watched a motor-generator while it's burning carbon, you know that the armature definitely takes (or gives?) a pounding.  Sometimes the balking machine practically seems like it could "walk" off the job. Granted, the beating never seemed to hurt the motor-generators, at least not for a very very long time, and an SA is basically of the same design. Right?But... while an engine-drive SA may be taking the same pounding as the above mentioned motor-generator, between the machine's engine noise and extra bulk, the beating may not be so noticeable, so all seems well. However, if you think about an engine drive's construction, with its armature supported by a single bearing and a coupler, I can see where the heavy "pounding" of carbon work could be destructive to the machine.That'd be my take on why to avoid heavy carbon work, it'd be interesting to know the repair folk's specific reasons.Good LuckLast edited by denrep; 12-04-2010 at 02:07 PM.
Reply:I've been hitting my 300d with 3/8 for a while but not all that often.The back of my truck hops when I hit it. I never used to care but now that I've read about it here I will move down to some 5/16 or smaller. For what it's worth she burns 3/8 very well but I don't want to kill my machine. Although I do love the sound of that diesel working hard I would think an SA- 400 would handle 3/8 but who am I to know.
Reply:I've been hitting my 300d with 3/8 for a while but not all that often.The back of my truck hops when I hit it. I never used to care but now that I've read about it here I will move down to some 5/16 or smaller. For what it's worth she burns 3/8 very well but I don't want to kill my machine. Plus I love the sound of that diesel working hard I would think a sa- 400 would handle 3/8 but who am I to know.
Reply:denrep, Your observations are acknowledged and noted  and it brings us right back to the original duty cycle issue that's based on the output and time relationship.  Would you (and Alfred) agree?MM200 w/Spoolmatic 1Syncrowave 180SDBobcat 225G Plus - LP/NGMUTT Suitcase WirefeederWC-1S/Spoolmatic 1HF-251D-1PakMaster 100XL '68 Red Face Code #6633 projectStar Jet 21-110Save Second Base!
Reply:Might not be alot but,   IF the shaft heats  up much from the heavy amp draw,  I can see where that could be a factor,  On the bearing lube,  just a thought,  Eric