Planning the electrical installation
56
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 contacts on the RMIO board are protected with varistors (250 V) 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 protective components at the RMIO board terminal block.
24 V DC
230 V AC
X25
1
RO1
2
RO1
3
RO1
X26
1
RO2
2
RO2
3
RO2
X27
1
RO3
2
RO3
3
RO3
Relay outputs
RMIO
230 V AC
Diode
Varistor
RC filter
Summary of Contents for ACS800-U7
Page 1: ...ACS800 Hardware Manual ACS800 07 Drives 45 to 560 kW ACS800 U7 Drives 50 to 600 hp ...
Page 4: ......
Page 28: ...Operation principle and hardware description 28 ...
Page 51: ...Planning the electrical installation 51 ...
Page 60: ...Planning the electrical installation 60 ...
Page 76: ...Electrical installation 76 ...
Page 84: ...Motor control and I O board RMIO 84 ...
Page 112: ...Maintenance 112 ...
Page 138: ...Dimensional drawings 138 Frame sizes R5 and R6 64778340_1 5 K ...
Page 139: ...Dimensional drawings 139 Frame sizes R7 and R8 68749930_1 7 C ...
Page 140: ...Dimensional drawings 140 IP54 and IP54R units of frame sizes R7 and R8 68749930_6 6 C ...
Page 148: ...3AFE64702165 Rev H EN 2012 09 19 Contact us www abb com drives www abb com drivespartners ...