Mitsubishi Electric MELSERVO-J4 MR-J4 TM Instruction Manual page 455

15. USING A DIRECT DRIVE MOTOR
15.4 Characteristics
15.4.1 Overload protection characteristics
An electronic thermal relay is built in the servo amplifier to protect the servo amplifier, the direct drive motor,
and direct drive motor power wires from overloads.
[AL. 50 Overload 1] occurs if overload operation performed is above the electronic thermal relay protection
curve shown in Fig. 15.2 [AL. 51 Overload 2] occurs if the maximum current is applied continuously for
several seconds due to machine collision, etc. Use the equipment on the left-side area of the continuous or
broken line in the graph.
When unbalanced torque is generated, such as in a vertical lift machine, the unbalanced torque of the
machine should be kept at 70% or lower of the motor's rated torque.
This servo amplifier has solid-state direct drive motor overload protection for each axis. (The direct drive
motor overload current (full load current) is set on the basis of 120% rated current of the servo amplifier.)
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