Overload Protection Characteristics - Mitsubishi Electric Melservo-J3 Series MR-J3-B Instruction Manual

13. SERVO AMPLIFIERS WITH A LARGE CAPACITY (30k TO 55kW)
13.8 Characteristics

13.8.1 Overload protection characteristics

An electronic thermal relay is built in the converter unit and drive unit to protect the servo motor, converter unit
and drive unit from overloads.
Overload 1 alarm (50) occurs if overload operation performed is above the electronic thermal relay protection
curve shown below. Overload 2 alarm (51) occurs if the maximum current flew continuously for several
seconds due to machine collision, etc. Use the equipment on the left-hand side area of the continuous or
broken line in the graph.
It is recommended to use the machine which generates unbalanced torque, e.g. a vertical lift application, so
that the unbalanced torque is not more than 70% of the rated torque.
10000
1000
100
10
1
0
Note 1. If operation that generates torque more than 100% of the rating is performed with an abnormally high frequency in a servo motor
stop status (servo lock status) or in a 30r/min or less low-speed operation status, the drive unit may fail even when the electronic
thermal relay protection is not activated.
2. Load ratio 100% indicates the rated output of each converter unit and drive unit. Refer to section 13.1.4 for rated output.
During rotation
(Note 2)
100 200
Load ratio [%]
Converter unit
Fig. 13.1 Overload protection characteristics
10000
1000
100
10
1
250 0
13 - 65
During rotation
During servo lock
(Note 2)
100
(Note 1) Load ratio [%]
Drive unit
200 250