Relay Output Contacts And Inductive Loads; Auxiliary Voltage Cables - ABB ACS800 Series Hardware Manual

Relay output contacts and inductive loads

Inductive loads (such as relays, contactors, generators) cause voltage transients
when switched off.
The relay contacts of the RMIO board are protected with varistors against
overvoltage peaks. In spite of this, 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 the protective components at the terminal block.

Auxiliary voltage cables

The auxiliary voltage (115, 230 V, etc.) cables must be rated for the required voltage
and current. Wire types H07V-U and H07V-R as specified by CENELEC HD 21 S2
Part 3 are highly recommended. A separate PE wire must be provided.
Varistor
230 VAC
RC filter
230 VAC
Diode
24 VDC
Relay outputs
RO (NC)
RO (C)
RO (NO)
RO (NC)
RO (C)
RO (NO)
RO (NC)
RO (C)
RO (NO)
Planning the electrical installation
67