take the 2 screws out of the yellow cap, and look inside...its either got a pulsecoder (most likely) or a resolver and tach.
I'm not at all familiar with AB controls, dunno if they need a tach. Fanuc didnt have a tach if they had a pulse coder- they used a frequency:voltage converter on their control to emulate the tach back to their drives, either 3.5 or 7 volts per thousand RPM was set via jumpers on the drive/controller. if you need a tach, this could be a issue.
Pulse coders came in only 2000/2500/3000 line resolutions- should be a tag under the yellow cap, or if the original tag on the motor is intact, the last digit says what encoder...-B001=2000, -B002= 2500, -B003=3000...any numbers in the tens or hundreds positions indicate other hardware, like a
-B201= a 2000 ppr encoder and a brake... encoders were A-B quadrature with Z marker, all complimentary outputs
are you using the 6047 Fanuc drive, or trying to control it with a A-B amp?