Using A Contactor Between The Drive And The Motor - ABB ACS800-04 Hardware Manual

58 Planning the electrical installation

Using a contactor between the drive and the motor


Implementing the control of the output contactor depends on how you select the
drive to operate.
When you have selected to use DTC motor control mode, and motor ramp stop, open
the contactor as follows:
1. Give a stop command to the drive.
2. Wait until the drive decelerates the motor to zero speed.
3. Open the contactor.
When you have selected to use DTC motor control mode, and motor coast stop, or
scalar control mode, open the contactor as follows:
1. Give a stop command to the drive.
2. Open the contactor.
WARNING! When the DTC motor control mode is in use, never open the
output contactor while the drive controls the motor. The DTC motor control
operates extremely fast, much faster than it takes for the contactor to
open its contacts. When the contactor starts opening while the drive
controls the motor, the DTC control will try to maintain the load current by
immediately increasing the drive output voltage to the maximum. This will
damage, or even burn the contactor completely.