What it is and what it does
The Mitsubishi MR-J4-500TM-EIP is a servo amplifier from the MELSERVO-J4 series, rated for 5 kW motor output. It is the drive stage that receives motion commands from a controller and powers a compatible servo motor, closing the position/speed/torque loop. This is the part that sits in the cabinet between the motion controller and the motor — no controller, no motor, just the amplifier.