Protecting The Relay Output Contacts And Attenuating Disturbances In Case Of Inductive Loads; Considering The Pelv Requirements At Sites Above 2000 M (6562 Ft) - ABB ACQ810-04 Hardware Manual

44 Planning the electrical installation
Protecting the relay output contacts and attenuating
disturbances in case of inductive loads
Inductive loads (relays, contactors, motors) cause voltage transients when switched
off.
The relay outputs on the drive are protected with varistors (250 V) against
overvoltage peaks. In addition, it is highly recommended to equip inductive loads with
noise attenuating circuits (varistors, RC filters [AC] or diodes [DC]) in order to
minimize the electromagnetic emissions 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, not at the
relay output.
Relay output
Relay output
Relay output
Considering the PELV requirements at sites above 2000 m
(6562 ft)
WARNING! Do not use a voltage greater than 48 V for the relay outputs of
drive module at installation sites above 2000 meters (6562 feet). Use of a
voltage greater than 48 V may damage the drive and can cause malfanction
and physical injury. The Protective Extra Low Voltage (PELV) requirements are not
fulfilled if a relay output is used with a voltage greater than 48 V.
Varistor
230 V AC
RC filter
230 V AC
Diode
24 V DC