Mitsubishi Electric MELSERVO-J3W Series, Instruction Manual

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14. USING A DIRECT DRIVE MOTOR
14 - 61
14.7 Characteristics
14.7.1 Overload protection characteristics
An electronic thermal is built in the servo amplifier to protect the servo amplifier, the direct drive motor, and direct
drive motor power lines from overloads.
Overload 1 alarm (50. ) occurs if overload operation performed is above the electronic thermal protection curve
shown in fig. 14.2. Overload 2 alarm (51. ) 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.
For the system where the unbalanced torque occurs, such as a vertical axis system, it is recommended that the
unbalanced torque of the machine be kept at 70 or less of the motor's rated torque. When mounting MR-J3W-
44B closely, use it with 90 or lower of the effective load ratio.
The MR-J3W 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 115 rated current of the servo amplifier.)
Operat
ion t
im
e [
s]
1000
100
10
1
0.1
0 50 150 200 250 300 100
Servo lock
Operating
(Note) Load ratio [ ]
MR-J3W-44B/MR-J3W-77B/MR-J3W-1010B
Note. If operation that generates torque more than 100 of the rating is performed with an abnormally high frequency in a direct drive motor
stop status (servo-lock status) or in a 30r/min or less low-speed operation status, the servo amplifier may malfunction regardless of
the electronic thermal protection.
Fig. 14.2 Electronic thermal protection characteristics