Delta ASD-A2-0121 Series User Manual page 55

ASDA-A2
(b) If the external load torque exists, the motor is in reverse rotation.
Usually, the motor is in forward rotation, which means the torque output direction of the motor
is the same as the rotation direction. However, in some applications, the direction of torque
output is different from the rotation. In this situation, the motor is in reverse rotation. The
external energy goes into the servo drive through the motor. The diagram below is one
example. When the external force direction is the same as the moving direction, the servo
system has to use the force of the opposite direction to keep the speed and stability. Huge
amount of energy will return to the servo drive at the moment. When DC-BUS is full and
unable to store the regenerative energy, the energy will be led to the regenerative resistor
and consumed.
馬達輸出負功
Negative torque: TL × Wr
For safety reasons, please calculate it by considering the safest situation.
For example, when the external load torque is the +70% rated torque and the rotation
reaches 3000 r/min, then take 400 W (the rated torque is 1.27 Nt-m) as the example. The
user has to connect the regenerative resistor of 40, which is
2 × (0.7 × 1.27) × (3000 × 2 × π／60) = 560 W.
2-16
正功
Positive
Negative Torque
Torque
TL: external load torque
馬達轉速
Motor Speed
External Load Torque
外部負載扭矩
Motor Output Torque
馬達輸出扭矩
負功
Negative Torque
Chapter 2 Installation
正功
Positive
Torque