Selection Suggestion Of Ac Drive - Canworld CDE360 Series Manual

CDE360 Vector Control AC Drive Chapter 2 Product Information
Figure 2- 8 Dust excluding plate B

2.7 Selection Suggestion of AC Drive

When select the AC drive, following conditions such as the technical requirements of the AC
drive,the application fields of the AC drive and the characteristics of the load should be explicit. At
the same time, the adaptable motor,output voltage and rated output current should be considered
comprehensively. As a result, the type and the running mode can be selected.
The fundamental principle is that the rated load current of the motor can not exceed the rated
current of the AC drive. Generally, the user can select the matching capacity of the motor according
to the user manual and compare the Rated motor current with the one of the AC drive. If doing so,
the overload capacity of the AC drive is significant for the start and brake process.
If there is transient overload during the running, the load speed will vary according to the transient
overload. And if the request for the accuracy of the speed is strict, please consider enlarging the
power of the AC drive.
Fans and water pumps: the requirement for overload is not strict. Because the torque of the load is
proportional to the square of the speed, the load is light when the speed is low (Here, roots blower is
not included); and because these loads have no restrict requirements for the accuracy of the speed,
the VF mode of square torque can be selected.
Constant torque loads: most loads have the characteristics of constant torque, but they have not
restrict requirements for the accuracy of the speed and the dynamic performance. The application
fields are as extruder, blender, conveyor belt, transport vehicle in the plant and the translational
mechanism of the crane. In this instance, the V/F running mode of constant torque can be selected.
Controlled objectives which have requirements of certain dynamic and static indexes: these
loads have the requirements for hard mechanical characteristics at low speed, so that the
specification of dynamic and static indexes can match the productive technology. In this instance,
the VF control or vector control can be selected.