On the Servo Motor Braking Mode and Principle2016-11-09
Dynamic brake by the dynamic braking resistor, in the event of failure, emergency stop, power outages through the energy consumption brake to reduce the mechanical servo motor feed is generally in the servo motor U, V, W phase leads to the three lines above respectively A resistor on the string, the three resistors connected to a relay, the servo motor in the normal work of the relay is to pull the three phase line is not shorted, when the servo motor to brake the relay to release three A phase line together to start the brake.
Regenerative braking is when the servo motor decelerates or stops the energy generated by the brake to feed back to the DC bus through the inverter circuit. The RC circuit absorption. Electromagnetic braking is the mechanical device to lock the motor shaft.
The difference between the three (1) Regenerative braking must be in the normal work of the server to work, in the case of failure, emergency stop, power failure, etc. can not brake the motor. Dynamic brake and electromagnetic brake work without power. (2) regenerative braking work is the system automatically, and dynamic braking and electromagnetic brake work to be external relay control. (3) The electromagnetic brake is normally started after SV OFF, otherwise it may cause the amplifier to overload. Dynamic brake is normally started after SV OFF or main circuit power off, otherwise it may cause the dynamic braking resistor to overheat.
Select the accessories of the note (1) Some systems, such as transmission devices, lifting devices require servo motor to stop as soon as possible. In the failure, emergency stop, power failure, the server does not regenerate the brake can not slow down the motor. While the system's mechanical inertia and larger, then need to use dynamic brakes Dynamic brake selection depends on the severity of the load, the motor speed and so on. (2) some systems to maintain the mechanical device of the static position required to provide greater motor output torque and stop a long time, if the use of servo self-locking function will often result in motor overheating or amplifier overload. In this case, select the motor with the electromagnetic brake. (3) Yasukawa's servers have built-in regenerative braking unit, but when the regenerative braking more frequent may cause the DC bus voltage is too high, then need to reprovision the regenerative braking resistor. Regenerative braking resistor need to reprovision, with how much of the regenerative braking resistor can refer to the sample instructions. It should be noted that the number of times of braking on the sample list is the data of the motor at no load. In actual selection, the inertia ratio should be calculated according to the load inertia of the system and the motor inertia of the sample. Then divide the number of brakes on the sample list by (inertia ratio + 1). The data thus obtained is the number of permissible braking times.
