MTFCA Forum

What is the casting number on the late mag ring, used until the end of production?

T-4389 is the factory number for the last version of the cast iron frame that had a starter notch and used 3/16" copper. It first appeared in April 1921 and was used to the end of production.

Thanks, R. V. . I'm looking at a mag ring from a Canadian engine. It has the starter cut out and single stack coils but I don't know the original wire thickness. As best I can make out, the casting number looks to be T 5932 B . Any Canadian T owners: are canadian T casting numbers THAT far off from USA numbers. I may not be reading the casting number correctly; number is hard to read.

As far as I have been able to tell from having rewound many thousands of field coils, all mag frames that have "Made in Canada" cast into them used the 3/16" copper. Further, on all of them, the height of the poles is considerably shorter than on US-made frames, so in rebuilding one of those you have got to be extra careful as there is very little leeway available to you in the finished height of the individual windings.