Inrush Currents At Power-On Of Main Circuit And Control Circuit - Mitsubishi Electric MR-J4 Instruction Manual

18. MR-J4-03A6 SERVO AMPLIFIER
(2) Permissible load to motor inertia when the dynamic brake is used
Use the dynamic brake under the load to motor inertia ratio indicated in the following table. If the ratio is
higher than this value, the servo amplifier may burn. If there is a possibility that the ratio may exceed the
value, contact your local sales office.
The values of the permissible load to motor inertia ratio in the table are the values at the maximum
rotation speed of the servo motor.

18.7.4 Inrush currents at power-on of main circuit and control circuit

Since large inrush currents flow in the power supplies, use circuit protector. For circuit protectors, it is
recommended that the inertia delay type, which is not tripped by an inrush current, be used. Refer to section
18.8.4 for details of the circuit protector.
This following table indicates the inrush current (reference data) when the power of output side of power unit
is turned on in the conditions: main circuit of 55.2 V DC, control circuit of 26.4 V DC, and wiring length of 1m.
Servo amplifier
MR-J4-03A6
Servo motor
HG-AK0136
HG-AK0236
HG-AK0336
POINT
The inrush current values can change depending on frequency of turning on/off
the power and ambient temperature.
Main circuit power supply (PM/0)
70 A (attenuated to approx. 0 A in 1 ms)
Permissible load to motor
inertia ratio [multiplier]
30
Inrush current
18 - 78
Control circuit power supply (24/0)
0.5 A (attenuated to approx. 0 A in 60 ms)