We are looking for someone to true up the commutator in our GP-9. Emd made a tool that replaced a brusholder and was used for this purpose. Does anyone know of a company providing this service or know of where we can rent the commutator truing tool. Thank you in advance for any leads.

Mike Tillger
Preservation Specialist
Steamtown National Historic Site
michael_tillger AT nps.gov
please replace the word AT with the appropriate symbol, no spaces

Mike,

You guys need to try and contact Jack Wheelihan who lives in the Chicago, Ill area. Jack is our local in-house railfan, Mr. EMD everything! I do not know if Jack hangs out here on RYPN but I do know that he hangs out on Trainorders in the Steam Discussions, you could try and page him there.

If that does not work, try contacting me direct and I will run down a number for Jack. I do not have one at my finger tips, but with-in a few calls I could run it down.

Best of luck,

This does not have to specifically be a tool for only emd generators. This type of tool is used in the generator industry. I have turned commutators on generators in place on fishing boats. It is fairly easy to do. Finding a tool for EMD would be great but if not try a generator repair business who does field work.

Mike,
See if this will help you.
http://www.idealindustries.com/products ... /index.jsp
Leverett Fernald
Downeast Scenic Railroad

Mike, when you say "turning tool" it implies removing a fair bit of material. This is usually done in a lathe with a carbide or diamond (which gives a finer finish) tool bit.

Anything EMD provided that replaced the brushes was probably like a very stiff rubber eraser with grit in it. This will remove surface oxidation, BUT if the surface is out of round it will just follow this out of round surface and give you a nice shiny out of round surface.

It may be possible to "turn" the commutator in-place by using a small (and very rigid) linear slide with a fine thread leadscrew to translate a cutting tool across the surface and "turn" it back into a nice round shape. This followed by one of the "rubber eraser's" in the brush holder can (if done carefully) give you a nice round oxidation free shiny surface.

It's important to remember that most of the material removed will be copper (chips and or dust) and will be conductive. Will probably work best with a good strong vacuum cleaner nozzle as close as possible to the active "turning" surface to get as much of this "junk" out of the area as you can. This will reduce cleanup and arcing/pitting after you return the unit to service.

Depending on how bad the surface is, you could try the "eraser" method first. But if the commutator is badly out of round the brushes will bounce and then arcing and pitting will occur, which will mean you have to do the job again sooner than otherwise necessary.

Hope this helps, Kevin