• Check that the power-loss ride-through function of the drive is enabled with parameter
30.31.
• Set parameter 21.01 (in vector mode) or parameter 21.19 (in scalar mode) to make
flying start (starting into a rotating motor) possible. If the installation is equipped with a
main contactor, prevent its tripping at the input power break. For example, use a time
delay relay (hold) in the contactor control circuit.
WARNING!
Make sure that the flying restart of the motor will not cause any danger. If you are
in doubt, do not implement the Power-loss ride-through function.
￭ Using power factor compensation capacitors with the drive
Power factor compensation is not needed with AC drives. However, if a drive is to be
connected in a system with compensation capacitors installed, note the following restrictions.
WARNING!
Do not connect power factor compensation capacitors or harmonic filters to the
motor cables (between the drive and the motor). They are not meant to be used
with AC drives and can cause permanent damage to the drive or themselves.
If there are power factor compensation capacitors in parallel with the 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
ABB recommends that you install a safety switch between the permanent magnet 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.
• For vector 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.
• For vector 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.
Guidelines for planning the electrical installation 79
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