Mitsubishi Electric Melservo-Jet MR-JET G-N1 Series, User Manual

Page: 49 / 140

5 CHARACTERISTICS
5.1 Overload protection characteristics
47
5
5
CHARACTERISTICS
5.1
Overload protection characteristics
An electronic thermal is built in the servo amplifier to protect the servo motor, servo amplifier and servo motor power wires
from overloads.
The actual overload protection level is lower than the electronic thermal protection curve of the servo amplifier and servo
motor used.
[AL. 050 Overload 1] occurs if overload operation performed is above the electronic thermal protection curve shown below.
[AL. 051 Overload 2] occurs if the maximum current is applied continuously for several seconds due to machine collision, etc.
Use the equipment within the overload protection level indicated on the left side of the continuous or dotted lines in the
following graphs.
For machines where unbalanced torque occurs, such as a vertical axis system, the unbalanced torque should be kept at 70 %
or lower of the rated torque.
This servo amplifier has a servo motor overload protection function. (The servo motor overload current is set on the basis of
115 % rated current (full load current) of the servo amplifier.)
The servo amplifier may malfunction regardless of the electronic thermal protection if torque exceeding 100 % of the rated
torque is generated too frequently while the servo motor is stopped (servo-lock status) or being operated at low speeds of 50
r/min or less.
Graph of overload protection characteristics
The following table lists servo motors and corresponding graphs of overload protection characteristics. The overload
protection characteristics depend on the servo motor.
■
Characteristic a
Rotary servo motor Graph of overload protection
characteristics
HG-KNS HG-SNS
13   Page 47 Characteristic a
23
43
73 52
102

Page 48 Characteristic b

152
202
302

Page 48 Characteristic c
100 200 300 400 500 600 0
10
1
100
1000
Operating time [s]
Load ratio (rated current ratio of rotary servo motor) [%]
: In servo-lock
: In operation