Implementing A Safety Switch Between The Drive And The Motor - ABB ACS880-17 Hardware Manual

84 Guidelines for planning the electrical installation
If there are power factor compensation capacitors in parallel with the three phase input of
the drive:
1. Do not connect a high-power capacitor to the power line while the drive is connected.
The connection will cause voltage transients that may trip or even damage the drive.
2. If capacitor load is increased/decreased step by step when the AC drive is connected
to the power line, make sure that the connection steps are low enough not to cause
voltage transients that would trip the drive.
3. Check that the power factor compensation unit is suitable for use in systems with AC
drives, ie, harmonic generating loads. In such systems, the compensation unit should
typically be equipped with a blocking reactor or harmonic filter.
Implementing a safety switch between the drive and the
motor
We recommend to install a safety switch between the permanent magnet synchronous
motor and the drive output. The switch is needed to isolate the motor during any
maintenance work on the drive.
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
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 on page 85.