ABB ACS880 Electrical Planning Instructions page 34

34 Electrical planning guidelines
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]) 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.
1 Relay output
2 Varistor
3 RC filter
4 Diode
230 V AC
1
230 V AC
+ 24 V DC
2
3
4