Testing Shunt Coils

admin

I have my exciter cage off and was able to get to the leads coming from the shunt coils. I have a digital multimeter and set it to ohms. Its an automatic ranging meter. I set it to the lowest setting since I'm expecting about 40 ohms.I found the leads coming from the 2 oclock shunt coil and probed. Nothing. Same result with the other coil.I started my tests with the two wires going to the shunt coils that were coming from the generator and didn't get a reading. I figured it was bad wires (hoped). I ended up pulling the exciter cage and getting to the shunt coils leads. So no reading means open coils?If that is the case and I have to replace the shunt coils how difficult is the process?I read that they are pressed in. What about the other coils that are in the generator? Are they pressed in as well or are they easy to get out?http://www.facebook.com/groups/sa200weldersCurrent machines:Hobart G600 Powered by 1967 Chrysler LH-318 (Project)Hobart GF-250(Traded)68 Redface81 Blackface
Reply:Originally Posted by shanghydI have my exciter cage off and was able to get to the leads coming from the shunt coils. I have a digital multimeter and set it to ohms. Its an automatic ranging meter. I set it to the lowest setting since I'm expecting about 40 ohms.I found the leads coming from the 2 oclock shunt coil and probed. Nothing. Same result with the other coil.I started my tests with the two wires going to the shunt coils that were coming from the generator and didn't get a reading. I figured it was bad wires (hoped). I ended up pulling the exciter cage and getting to the shunt coils leads. So no reading means open coils?If that is the case and I have to replace the shunt coils how difficult is the process?I read that they are pressed in. What about the other coils that are in the generator? Are they pressed in as well or are they easy to get out?
Reply:Originally Posted by shanghyd............................... I have a digital multimeter and set it to ohms. Its an automatic ranging meter. I set it to the lowest setting since I'm expecting about 40 ohms..............................
Reply:Yes the coils are pressed in. They are pushed towards the engine direction after the stator is removed. Aways push it the same direction, Push in the wrong direction and they may lock in place. You need a large press to do the job. plus custom pushers as the end of the press is to large. Must miss the other coils.You should have a near 0 reading on your ohm meter. You may find an open connection after you remove the stator assembly from the engine. The coils are spliced together and One of the splices at the engine end could be open or one of the coils has blown open.
Reply:I haven't taken the generator off yet but I had a closer look at the coils. I can see the dovetail slot that the shunt coils are pressed into. Shouldn't be a problem having them pressed in or out.As for the other coils how are they removed? Once I get the generator out will they come out easily?http://www.facebook.com/groups/sa200weldersCurrent machines:Hobart G600 Powered by 1967 Chrysler LH-318 (Project)Hobart GF-250(Traded)68 Redface81 Blackface
Reply:Yes, you should get a 46ohm +/- reading thru the main generator shunt coils hooked in series as they are when installed (VOM set on 200 scale).  An open reading means one (both is unusual) coil has an open, the series connection is open or there's a break in one of the two coil/leads connections.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:Only take the one that is confirmed bad The other coils are left in place. That is what the adapter will allow you to do. The splice in the center of the two coils is known to fail. If you have time pull the generator first and inspect. You might be able to fix it with out parts. If you do not have one. contact lincoln electric and give them your code number and ask for the diagrams for your welder. They will be happy to fax or e-mail them to you. Get them be e-mail they are much cleaner and you can print them up nice and big.
Reply:I found a broken wire from the 7 oclock shunt coil. The wires are brittle. This thing must have been sitting at the bottom of a lake or something.I guess I'll pull the generator and have a better look at everything.http://www.facebook.com/groups/sa200weldersCurrent machines:Hobart G600 Powered by 1967 Chrysler LH-318 (Project)Hobart GF-250(Traded)68 Redface81 Blackface
Reply:In case anyone wants to see pictures of the mess I'm working with I have uploaded some to photobucket. Not sure if you have to login to see them. The link below is to one picture but you should be able to select "Next Picture" or some other link to see all the pictures. Pictures are pretty massive in size.http://s724.photobucket.com/albums/w...rent=coil2.jpghttp://www.facebook.com/groups/sa200weldersCurrent machines:Hobart G600 Powered by 1967 Chrysler LH-318 (Project)Hobart GF-250(Traded)68 Redface81 Blackface
Reply:Cool V8 keep us posted.1990 SA 200Miller 225  Rip Miller302Miller 135Lincoln 200 MigHypertherm 600 PlasmaPlasma Cam Cutting TableMikita Cold SawJL Welding Tx . com
Reply:Anyone ever wound some shunt coils by hand?If so, does anyone know the gauge of the wire and the number of turns?http://www.facebook.com/groups/sa200weldersCurrent machines:Hobart G600 Powered by 1967 Chrysler LH-318 (Project)Hobart GF-250(Traded)68 Redface81 Blackface
Reply:Hmmm....I ‘spose you could try to reverse engineer the old ones.A slow turning fixture with a counter would probably be helpful in making  tightly packed bundles with the correct number of turns.Good Luck
Reply:I emailed a website that sells custom rewound shunt coils and asked if they could give me the information I needed to rewind my own coils. Hopefully I can get the information. If not I guess I count the turns as the wire comes off the bobbin and go from there.http://www.facebook.com/groups/sa200weldersCurrent machines:Hobart G600 Powered by 1967 Chrysler LH-318 (Project)Hobart GF-250(Traded)68 Redface81 Blackface
Reply:Any members ever pressed these shunt coils out of the generator? I'm thinking maybe an H frame will work to press them out.http://www.facebook.com/groups/sa200weldersCurrent machines:Hobart G600 Powered by 1967 Chrysler LH-318 (Project)Hobart GF-250(Traded)68 Redface81 Blackface
Reply:We have an H frame hydraulic press. We made a adapter that just fits the slot and the end of the coils. It allows  the press to push through with out touching the other coils.Make it to fit the end of your press ram. With out slipping off. push the coil through toward the engine end. Push the new or repaired one in the same direction.Be careful not to catch any of the other wires.
Reply:I bought an H Frame press today. I still have to pick it up. Do you have a picture of the adapter that you use?http://www.facebook.com/groups/sa200weldersCurrent machines:Hobart G600 Powered by 1967 Chrysler LH-318 (Project)Hobart GF-250(Traded)68 Redface81 Blackface
Reply:I will have to find it. it is stored some where. I will try to post it Wednesday night.we don't do this very often .
Reply:Its cool, I got the shunt coils out. I used a slim piece of steel that fit between the housing and in the dovetail slot.I have pictures on www.sa200.org/repair.htmlMy next step is to count the number of turns of wire as they come off the bobbin and try to rewind these shunt coils. $245 is a good price for replacement coils but I want to try to rewind some.http://www.facebook.com/groups/sa200weldersCurrent machines:Hobart G600 Powered by 1967 Chrysler LH-318 (Project)Hobart GF-250(Traded)68 Redface81 Blackface
Reply:Great project so far.  I'll be interested to see how this all turns out."The reason we are here is that we are not all there"SA 200Idealarc TM 300 300MM 200MM 25130a SpoolgunPrecision Tig 375Invertec V350 ProSC-32 CS 12 Wire FeederOxweld/Purox O/AArcAirHypertherm Powermax 85LN25
Reply:After you wind them. you will want to lock the wires in place with some motor lacquer.You do not want the wires to move around and heat up then break again.
Reply:$245 is cheap, i paid $400 for mine but they are made in the u.s.a. and carry a 5yr warrenty, got them from www.weldmart.com in texas. i cant afford to have these things go out, when my sa doesn't run we dont make money!
Reply:Hypriweld.com sells them for 245 and all copper