Delta ASDA-B2-F Series User Manual

Contents

ASDA-B2-F InstallationSeptember, 2015 2-92Take the motor (400 W with frame size 60) as the example, the cycle of back and forth operationis T = 0.4 sec, the maximum speed is 3000 r/min and the load inertia is 7 times to the motorinertia. Then, the needful power of regenerative resistor is 2 × ((7+1) ×1.37 – 8) / 0.4 = 14.8 W. Ifit is smaller than the built-in capacity of regenerative resistor, the built-in 60W regenerativeresistor will do. Generally speaking, when the need of the external load inertia is not much, thebuilt-in regenerative is enough. The diagram below describes the actual operation. The smallerpower of the regenerative resistor it is, the more energy it accumulates and the highertemperature it will be. When the temperature is higher than a specific value, AL005 occurs.(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 themotor is the same as the rotation direction. However, in some applications, the direction oftorque 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 oneexample. When the external force direction is the same as the moving direction, the servosystem has to use the force of the opposite direction to keep the speed and stability. Hugeamount of energy will return to the servo drive at the moment. When DC-BUS is full andunable to store the regenerative energy, the energy will be leaded to regenerative resistorand consumed.NegativeTorque PositiveTorque Negative TorqueMotor SpeedExternal Load TorquePositiveTorqueMotor Output TorqueNegative torque: TL × Wr TL: external load torqueFor safety reasons, please calculate it by considering the safest situation.For example, when the external load torque is +70% rated torque and the rotation reaches3000 r/min, then take 400W (the rated torque is 1.27 Nt-m) as the example, users have toconnect the regenerative resistor which is 2 ×(0.7×1.27) ×(3000 ×2 ×π／60) = 560 W, 60.