Delta Electronics none manual With Load

Chapter 6 Control Modes of OperationASDA-AB Series

For example:

If we use 400W servo drive, the time of repeat operation cycle is T = 0.4 sec, max. motor speed is 3000r/min, the load inertia = 7 × motor inertia, then the necessary the power of regenerative resistor = 2 x ( (7+1) × 1.68 - 8) / 0.4 = 27.2W. If the calculation result is smaller than regenerative power, we recommend the users to use the built-in 60W regenerative resistor. Usually the built-in regenerative resistor provided by ASDA-AB series can meet the requirement of general application when the external load inertia is not excessive.

The users can see when the capacity of regenerative resistor is too small, the accumulated power will be larger and the temperature will also increase. The fault, ALE05 may occur if the temperature is over high. The following figure shows the actual operation of regenerative resistor.

(2) With Load

When there is an external load torque, servo motor is in reverse rotation when external load greater than motor torque. Servo motor is usually in forward rotation and the motor torque output direction is the same as the rotation direction. However, there is still some special condition. If the motor output torque is in the reverse direction of rotation, the servo motor is also in the reverse direction of rotation. The external power is input into the servo drive through servo motor. The Figure 6.21 below is an example. The users can see the motor is in forward rotation at constant speed when a sudden external load torque change and great power is transmitted to regenerative resistor rapidly.

Motor Rotation Speed

External Load Torque

Motor Output Torque

Reverse	Forward	Reverse	Forward
Rotation	Rotation	Rotation	Rotation

External load torque in reverse direction: TL x Wr TL : External load torque

For the safety, we strongly recommend the users should select the proper resistance value according to the load.

6-38 Revision March 2008, Doc. Name: 2007PDD23000011