Protecting The Relay Output Contacts And Attenuating Disturbances - ABB ACS550-02 User Manual

ACS550-02/U2 User's Manual
Protecting the relay output contacts and attenuating disturbances in case
of inductive loads
Inductive loads (relays, contactors, motors) cause voltage transients when switched
off.
It is highly recommended to equip inductive loads 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 control board terminal block.
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Varistor
230 V AC
RC filter
230 V AC
Diode
24 V DC
Control
X1
board
Digital outputs
K1
19 X1C-1
20 X1C-2
21 X1C-3
K2
22 X1D-1
23 X1D-2
24 X1D-3
K3
25 X1E-1
26 X1E-2
27 X1E-3
Planning the electrical installation
25