As part of the gear hobbing project, I need to pick up a pulse rate generated by the hob axis. I have a Universal Magnetics Inc DC servo motor which I think came from an 8" floppy disk drive many years ago. (Nowadays if I had such a drive, I'd hang on to it like gold dust!).
It appears to have some form of tacho or encoder firmly affixed to the rear end, but with no sign of being able to open it to examine to see whether it is a tacho or an opto.
Any clues?