I think this idea works in theory???

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I think this would work in theory but could it actually work? A company I uesd to work for has a early 90's ackland 250 tiger cat welder sitting in the shead. It's bean sitting in there for about 3 years since we blew the egine in it and the owner decided to replace it instead of repair it. I tried to buy it from him then thinking I would fix it but for what ever reason he never really got back to me on weather or not he wanted to sell it. I forgot about the idea so there it sat and still sits 3 years later.Anyways I have to go there one day this week for some stuff so I figure I would see if I can pick it up for dirt cheap. I know the owner wants to clean the shead out. I don't want it as a project but rather for the Idle control module but that got me thinking. Since the engine is toast and half taken apart for the last couple of years and I want to take parts from that end anyways that would leave me with the complete generator. I for got to mention not that it matters reallt but its 250 amp ac/dc cc/cv machine.Now for the part that I think works in theory. Could I remove the entire engine assembly and replace it with an electic motor? Is this completely crazy or could this work. I realise It wouldn't be as good as buying a welder but if I end up having it laying around anyways heck why not. And before anyone tellls me to just by a welder I am not looking to buy one. Ok thats a lie I'm just not allowed to by anymore right know something about how many do I really need  But if I build one from spare parts then I didn't buy another one right? And this one I am trying to buy for parts I'm not buying a welder I'm buying parts for a welder. I might need you guys to back me on that one if she doesn't see it that way. But how could she notSo what do you all think? Is it possible or would it require to big of an electric motor? If it's stupid and impossible please don't burn me to bad for askingThanks for any thoughts you have on the idea,Josh
Reply:What you're wanting to build is called a motor-generator machine, where an electric motor is used to drive a DC generator, not to be confused with an engine-driven welder. Many of the very early industrial welders used this method before they were almost entirely replaced by the much more efficient and cheaper transformer-rectifier type machines (which are, in turn, getting largely supplanted by even more efficient inverter machines). .Because you are converting electrical energy to mechanical energy (the drive motor) and then mechanical energy back into electrical energy (the generator) you will be dealing with some serious efficiency losses. You will have to use a motor that will require much more power to run the machine that would be required by even an inefficient 250 amp transformer machine.In the end you'll just end up with a big heavy machine that has all the noise and inefficiency of an engine-driven welder, but without the advantage of portability.Visit Tensaiteki.com
Reply:Josh - Can it be done?  Sure.  But you'd need 3-phase power as it's going to take a decent size motor (I'm guessing 15-20hp minimum) and would be a little more trouble than it's worth IMO.Personally, it's just an engine - fix it.  If you ask me - I guess you did  - a 250A AC/DC CC/CV portable machine is a whole lot more useful than the same as a 3-phase electric drive.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:You said that the motor blew, is the block cracked?If not, rebuild it.  If you don't know how, bring it to your local highschool small engines class along with some donuts for the teacher.Small engines are pretty quick & easy to rebuild.Buy American, or don't whine when you end up on the bread line.
Reply:Originally Posted by duaneb55Josh - Can it be done?  Sure.  But you'd need 3-phase power as it's going to take a decent size motor (I'm guessing 15-20hp minimum) and would be a little more trouble than it's worth IMO.Personally, it's just an engine - fix it.  If you ask me - I guess you did  - a 250A AC/DC CC/CV portable machine is a whole lot more useful than the same as a 3-phase electric drive.
Reply:What's the model on the onan.  I'm guessing it's around 20HP.  The engine on the AEAD-200 is rated at 18HP I think.  18HP on a 200A machine so I'm guessing you'd need 22HP or so on a 250A machine.  Too small of an engine and it'll probably still be usable.  You'd just bog the engine at max output.  How often do you use 250A?  Too large of an engine and you'll be fine, but you'll just burn a little more fuel.  Setting the governer may be a pain.  Modifying the high/low idle for a different engine will probably be more of a pain.  You might just set the high idle by hand and leave it there.Last edited by AndyA; 01-17-2011 at 03:29 PM.Dynasty200DX w/coolmate1MM210MM VintageESAB miniarc161ltsLincoln AC225Victor O/A, Smith AW1ACutmaster 81IR 2475N7.5FPRage3Jancy USA1019" SBAEAD-200LE
Reply:I've heard that parts for the onans are expensive especially when doing a full rebuild. I don't recall exactly what was wrong with it I think it blew a piston or rod something like that.
Reply:Where are you located? I have some 4cyl diesel Onan motors that are available.
Reply:A thrown rod is the most common failure and an easy fix.  Contact member onanparts.com (TJ) http://onanparts.com/ and he can help you determine what it will cost to get it back together and running.There's also lots of Onan parts and complete engines available on eBay as well.  If the current engine is a total loss due to a broken block (rare), an eBay engine may require changing out the crankshaft for the original to allow coupling up to the welder rotor.If you can get the Tiger Cat a song - or for just hauling it off - it would be well worth putting that Onan back together.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:Well if thats the case then I shall see what I can do. I haven't had a chance to swing buy and talk to the owner yet but will try to stop in one morning before I go to work and see if I can swing a deal. I'm sure he won't give it to me for free because hes really cheap that way. So if I gotta pay a bit how much do you think it's worth? What I really should be asking is what price is starting to become not a great deal? I know I haven't done a very good job of providing any info on it so just your best guess is all I'm after. I tend to get tunnel vision when it comes to things I want so it's a good idea for me to come up with a walk away price before hand.Thanks for any help,Josh
Reply:Can't add much to what Steve said.  If he seems insulted by an offer of $50 point out that you're the one taking the gamble as you don't even know if it still welds/generates.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!