Hardware Manual

82 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. See also section Implementing a bypass connection on page 82.
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.
Implementing a bypass connection
If bypassing is required, employ mechanically or electrically interlocked contactors
between the motor and the drive and between the motor and the power line. Ensure
with interlocking that the contactors cannot be closed simultaneously.
WARNING! Never connect the drive output to the electrical power network.
The connection may damage the drive.