ABB ACS350 Series, User Manual

Page: 34 / 314

Planning electrical installation
34
Protecting the relay output contact and attenuating disturbances in case
of inductive loads
Inductive loads (relays, contactors, motors) cause voltage transients when switched
off.
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 I/O terminal block.
Residual current device (RCD) compatibility
ACS350-01x drives are suitable to be used with residual current devices of Type A,
ACS350-03x drives with residual current devices of Type B. For ACS350-03x drives,
other measures for protection in case of direct or indirect contact, such as separation
from the environment by double or reinforced insulation or isolation from the supply
system by a transformer, can also be applied.
Selecting the control cables
All analog control cables and the cable used for the frequency input must be
shielded.
Use a double-shielded twisted pair cable (Figure a, e.g. JAMAK by NK Cables) for
analog signals. Employ one individually shielded pair for each signal. Do not use
common return for different analog signals.
24 VDC
230 VAC
230 VAC
Diode
Varistor
RC filter
Drive
relay
output
Drive
relay
output
Drive
relay
output