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 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.
Using 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.
Protecting the contacts of relay outputs
Inductive loads (relays, contactors, motors) cause voltage transients when switched off.
The relay contacts on the drive control unit are protected with varistors (250 V) against
overvoltage peaks. In spite of this, it is highly recommended that inductive loads are equipped
with noise attenuating circuits (varistors, RC filters [AC] or diodes [DC]) in order to minimize
the EMC emission at switch-off. If not suppressed, the disturbances may connect capacitively
or inductively to other conductors in the control cable and form a risk of malfunction in other
parts of the system.
Install the protective component as close to the inductive load as possible. Do not install
protective components at the relay outputs.
Guidelines for planning the electrical installation 79
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