Mitsubishi servo amplifier MR-J4-70A The Mitsubishi MELSERVO-J4 series MR-J4-70A is a high-performance servo amplifier designed for precise motor control. It can handle a fuse current rating of 20A and a fuse voltage rating of 300VAC for its main circuit power supply. With an instantaneous maximum output power rating of 2625W and an instantaneous power failure tolerance rating of 1150W, it ensures reliable performance. The MR-J4-70A servo amplifier has a built-in regenerative resistance rating of 20W and an inverse efficiency rating of 85%.