What is a Miller Bobcat 225g exactly???

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This probably sounds like a stupid question... But what exactly is a Miller Bobcat 225G?  By this I mean, how does it work?  Is it a generator type machine, similiar to a SA200, or does the gas engine run a generator, which in turn powers a cheap welding machine built in, somewhat like a cheap version of a Vantage or something?  I can't see it having an inverter type welder built in (technology of them is too old, and you can buy them too cheaply), but maybe some sort of transformer welder?The reason for this odd question, is I've had one on my rig for several years.  I originally had one of my SA200's on it, as I will again soon hopefully.  Anyway, when I rigged it up, I built reels for the leads.  I don't know the exact numbers, but I have probably 70' to 80' of 2/0 ground, and 100' or so of I think #1 for the stinger.  My SA200 welded great with this setup, other than the stinger lead would get rather warm if you ran a lot of 3/16" 7010.  I know a SA200 is a far superior DC welding machine than a Bobcat, but still, this is the 2nd bobcat I've had on this truck and they both weld like crap...  I need to buy some parts for both of my SA200's (somebody helped themselves to the carbeurators off both of them, and the idle solenoid off of one...), but I want to get them both fixed back up, and put one on my current rig, and the other on my new rig I'm going to build.My biggest question, is on the Bobcat, is the un-equal leads causing this.  I never thought about it, but seeing the problems Slowhand had with un-balanced leads on the inverter machines made me wonder about this.  I have used a couple of Lincoln Ranger 8's that had much shorter, more equal leads, and they ran a LOT better.  One of them, I welded road bore casing with, and I'm pretty sure I could have tested with that machine.  This Bobcat I have on the truck right now, I'd rather uphill pipe with 7018 because it will run up to 1/8" uphill decent.  It will run 5/32 flat, but won't "stay with it" trying to run uphill.  And it absolutely hates 6010 or 7010 downhill... It is manageable until you get past about 4 o'clock, then it turns into crap fast.  Doesn't matter what you do with the heat, it just won't stay with it...The main reason we have the Bobcat, is to run plastic fusion tools.  Most of my plastic tools are 110 volt, and you can run them off of a 3500 watt honda generator.  But I have an 8" machine, that the carriage, facer and heating iron are all three 220.  It takes between 6500 and 7000 watts to run this machine.  The Bobcat works great to run this.  So we'll probably build a trailer to mount the Bobcat on, and also keep all the plastic tools on it.  But I want REAL welding machines back on my trucks...
Reply:Apples and oranges.  The 200s are a pure DC machine, and will hands down out live both of those bobcats.  The bobcats are an AC alternator, and have diodes to rectify the power to DC for welding.  It will not weld as nice, new, compared to a 30, 40, or 50 year old 200.  As far as the leads, I don't think they are your problem.  I read the post from Slowhand, and my understanding is his problems were from interference from another machine welding right next to him on the same piece.Remember a bobcat is $4000 new.  A new version of an SA200 is $14000.  maybe some of it.Bruce DeLaetHeavy Equipment Mechanic and Welder1948 SA-200 short hood1949 LincWelder 1801963 SA-200 red faceMiller S-32-P
Reply:I think 7A749 and  delaet20 pretty well hit the nail on the head here.  Ive never tried one and the only guy i know that has one is a mechanic. I ask him one time how he likes it and all he said was he needed the aux a/c.I downloaded the schematic and didnt see any IGB's so it aint a chopper i dont believe. And only seen one generator so probably like 7A749 said - a rectified single phase unit. 60hz.  It aint no inverter either cause i dont see the circuity on there for all that business.Without having an electronic dig circuit cable balance isnt as vital (imo).  But it wont hurt either.  Id probably say it would do the best with short cables. I say that because i feel it will drop volts when you crowd it and shorter leads might give it more to begin with.  Just a guess.Good luck manSlowhandLast edited by slowhand; 12-30-2012 at 12:00 PM.
Reply:Has anyone used a bobcat 225 and a Lincoln Ranger 8?  I always thought the bobcat was the miller version of a ranger 8...  Never used a miller but had 2 RangersTiger Sales:  AHP Distributor    www.tigersalesco.comAHP200x; AHP 160ST; MM350P,  Spoolmatic 30A; Everlast PowerTig 185; Thermal Dynamics 60i plasma.  For Sale:  Cobra Mig 250 w/ Push-pull gun.  Lincoln Wirematic 250
Reply:The circuit diagram for the 225g shows what is essentially a 220a engine driven buzz box.The output would be a choppy DC, without the purity of a DC generator.
Reply:Originally Posted by soutthpawHas anyone used a bobcat 225 and a Lincoln Ranger 8?  I always thought the bobcat was the miller version of a ranger 8...  Never used a miller but had 2 Rangers
Reply:Originally Posted by 7A749Every Bobcat I have run welded like crap. The Trailblazer is a marked improvement over the Bobcat for sure.Now, I have never had trouble with different length leads, but that's with a TB machine too. The Bobcats I ran all had similar length leads. Still, the arc wasn't anywhere near what it is on my TB. I have 300' of pos & 200' of neg, still stick welds very nice.Basically, being an AC alternator, you're not getting the benefit of true generated DC power & even the TB machines all produce their own separate weld current which is three phase, four pole rectified DC.I don't have anywhere near the experience with engine drive machines many here do, but I can say that Bobcat machines in general just can't even compete with their more advanced counterparts or DC generator machines. I can say from talking to a LOT of pipe guys that a lot of firing line jobs won't even let you test if you show up with one in the back of your truck.Too, the fact you have run a real DC machine then a Bobcat, you can clearly see the difference. I honestly don't think the leads are the biggest part of the problem. Inverter & chopper based machines like the Vantage are often sensitive to outside electrical interference. The Bobcat is neither, just a low cost mass produced engine drive welding machine.Maybe somebody else will have a better explanation.IMHO of course
Reply:Originally Posted by slowhandI think 7A749 and  delaet20 pretty well hit the nail on the head here.  Ive never tried one and the only guy i know that has one is a mechanic. I ask him one time how he likes it and all he said was he needed the aux a/c.I downloaded the schematic and didnt see any IGB's so it aint a chopper i dont believe. And only seen one generator so probably like 7A749 said - a rectified single phase unit. 60hz.  It aint no inverter either cause i dont see the circuity on there for all that business.Without having an electronic dig circuit cable balance isnt as vital (imo).  But it wont hurt either.  Id probably say it would do the best with short cables. I say that because i feel it will drop volts when you crowd it and shorter leads might give it more to begin with.  Just a guess.Good luck manSlowhand
Reply:As the day goes by things heat up... If im right and it has a step-down transformer then that is probably what you feel. Not that its bad, just not ment for such abuse. Lol.  Whats the rated duty cycle on it?  With a 3/16" capping rod 8010g your looking at 125-145 amps @ 26 volts. On a firing line it better be rated @ 100%. Haha. At least most of them ive been on anyway. LolFilling with a 3 is  about 175 or so amps and 28 volts (give or take).  So between those is like 160 amps at 27 volts.Last edited by slowhand; 12-30-2012 at 03:19 PM.
Reply:Haha. What it is - is crowding that rod dropping the voltage.  Then its up on the amps. Yea. It'll fry. How hot does that transformer get?We weld with KW. Lets say i need 4000 watts and my machine has the guts to give me 30 volts. 4000 ÷ 30 = 133, so i need 133 amps.  But lets say it can only put out 19 volts.... 4000 ÷ 19 = 210. Now i must have 210 amps. No the arc doesnt feel the same, nor will i like it, but thats all i'll get in that case.  A real good SA200 will put out 145 amps @26 volts and the heat was perfect. But on my XMT i use 125 amps  @30 volts and its perfect. Why? 145x26=3770, and 125x30=3750. See, KW.If that transformer, or the leads, get hot then the volts are going to drop. They have no choice. Lol. Then we are going to need more amps.  Put that on 60hertz and good luck man. It'll be a rough arc. That has no choice either.Last edited by slowhand; 12-30-2012 at 03:52 PM.
Reply:It's kinda funny, people will see my rig somewhere, and ask if I'm working on a pipeline around there... I'm like... "really??? Look at that piece of $hit machine... Do you REALLY think I'm welding on a pipeline with that???"  Yeah, the truck IS rigged up for it, but NOT with that machine... No WAY.  Not even if I could BS my way into a test somewhere with it...  I may be crazy, but I'm not stupid...  If you could make it work out, it would be a constant battle all day every day.  Until you burned it up anyway...I have run a carbon arc with this machine.  You can't use very big carbons, but it will work.  I probably SHOULDN'T do it, but I think in the back of my mind, well, if it smokes, more motivation to get one of my real machines back on the truck...LOL...Another thing, I don't know if all of these machines do this, but this thing DRINKS the gas.  Uphill 7018, welding a trackhoe bucket back together or something of that nature, it'll drink 10gallons in 7 or 8 hours.  Which, it only idles down when it wants to.  Some days idler works right, sometimes it won't idle down for weeks.
Reply:heres a pic of my truck when I first rigged it up.  This is before I put the torches and all on it, and had a honda generator for auxilary power.  The honda generator got stolen from the Dodge dealership while I had it in having some work done to it. Attached Images
Reply:These are more recent pics of it... Attached Images
Reply:Stolen at the dealership?  I hope they paid for it, or being a dodge, took it of the bill for the tranny rebuild.Bruce DeLaetHeavy Equipment Mechanic and Welder1948 SA-200 short hood1949 LincWelder 1801963 SA-200 red faceMiller S-32-P
Reply:Originally Posted by delaet20Stolen at the dealership?  I hope they paid for it, or being a dodge, took it of the bill for the tranny rebuild.
Reply:Amazing.  I think I would have tried to sue them.  Honda generators are not cheep."It had close to 100,000 miles on it when that happened. I've got close to 450 horsepower to the wheels, maybe more than that with the Mack turbo I've got on it now."I tend to be a fan of keeping it close to stock.  They last longer that way.Bruce DeLaetHeavy Equipment Mechanic and Welder1948 SA-200 short hood1949 LincWelder 1801963 SA-200 red faceMiller S-32-P
Reply:I would keep both on the truck SA-200 for pipe and the Miller for power . Today you are better off with the gas 200 runs cheaper than a Vantage or DC-250. Upgrade to a alternator , big battery and inverter on the 200 for AC power.
Reply:My old S.A.200 used about 9.5 gallons a day. Today thats about $32.  My 200d Perkins or my vantage 300 Kubota will use under 4 gals. That's less than $16.   That's an average 10 hour day on a firing line keeping busy.
Reply:Bobcats are good for what they were designed for, aux power and a welder that a mechanic could stick things back together with.  I have owned two and one lincoln 250.  I liked the millers better than the 250 but again just as a mechanic.  When we went to HF or weld on Grouser bars I went to a lot bigger machine. I have owned 2 miller big 40s and one big 20.  I still prefer the sa 200s or the 3's.  The 200's do a great job but I prefer the dual continuous control machines.  My current SA300 will burn about 1.5 gals an hour unless I am really pushing it.  The 40 was a little more but the best is still the 1938 lincoln.  It uses about 4 gals a day at 600 amps, but it also weighs about 6200# and takes up all of the back of the service truck.  Of all the smaller machines I believe the TB is the best tho I have never owned one.  They guys a I talk to really like theirs.1938 Lincoln SA 600 1973 Lincoln SAE 3001984 Lincoln Sa 250DF800 Ford with 10 ton craneVictor and Harris torches.Rolair compressorSouthbend 13" latheAtlas Mill