Controlling a Motor for test bench
You probably need a motor-run capacitor to make the AC induction motor work properly. It does say 8uF on the label.

Also, I really, really doubt the first motor is a stepper motor. It states 100V, 50/60 hz. 100V is the Japanese line voltage standard, and I have never seen a stepper motor with a specification in hz.

Edit Ok, the first motor is a 4IK25RGN-A. This is a 1/30th horsepower AC induction motor. 



Realistically, neither of these motors are appropriate at all for a servo system. They both look to be fractional HP induction motors. 

You can control speed of an AC motor with a variable-frequency drive. However, VFDs (and induction motors in general) do not have much 0 RPM torque, and don't provide  control of the actual motor position, just the motor RPM. 

Really, you need a brushed servo-motor, or a brushless AC servo-motor (or even stepper motors). All of these use a different mechanism to generate motion then an induction motor, which is actually a rotating transformer.