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15. SERVO AMPLIFIERS WITH A LARGE CAPACITY
30k TO 55kW
15.9.3 External dynamic brake
CAUTION
Use an external dynamic brake for the drive unit. Failure to do so will cause an
accident because the servo motor does not stop immediately but coasts at an
emergency stop and such conditions. Ensure the safety in the entire system.
POINT
Configure up a sequence which switches off the magnetic contactor of the brake
unit after (or as soon as) the servo on (SON) has been turned off at a power
failure or failure.
For the braking time taken when the dynamic brake is operated, refer to section
15.8.3.
The brake unit is rated for a short duration. Do not use it for high duty.
The specifications of the input power supply for external dynamic brake are the
same as those of the converter unit control circuit power supply.
Operation timing is the same as that for servo amplifiers with 22kW or less. Refer
to section 12.6.
Dynamic brake operates at occurrence of alarm, servo emergency stop warning
(AL.E6), and when power is turned off. Do not use dynamic brake to stop in a
normal operation as it is the function to stop in emergency.
Maximum usage time of dynamic brake for a machine operating under
recommended load inertia moment ratio is 1000 time while decelerating from
rated speed to a stop with frequency of once in 10 minutes.
Be sure to make emergency stop (EMG EM1) valid after servo motor stops
when using emergency stop (EMG
EM1) frequently in other than emergency.
(1) Selection of dynamic brake
The dynamic brake is designed to bring the servo motor to a sudden stop when a power failure occurs or
the protective circuit is activated. When using the external dynamic brake, assign the dynamic brake
interlock (DB) to any of CN1-22, CN1-23, CN1-24, CN1-25 and CN1-49 pins in parameter No.PD13 to
PD16 and PD18.
Converter unit Drive unit Dynamic brake
MR-J3-CR55K
MR-J3-DU30KA
DBU-37K
MR-J3-DU37KA
MR-J3-DU30KA4
DBU-55K-4
MR-J3-CR55K4
MR-J3-DU37KA4
MR-J3-DU45KA4
MR-J3-DU55KA4
(2) Connection example
Use the following wires to connect the dynamic brake.
Dynamic
brake
Wire[mm
2
] (Note)
a b U V W
DBU-37K
2 14
DBU-55K-4
Note. Selection condition of wire size is as follows.
Wire type: 600V Polyvinyl chloride insulated wire (IV wire)
Construction condition: One wire is constructed in the air
