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SIRIUS
Siemens Industry, Inc. Industrial Control Product Catalog 2017
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2
COnTACTORS And
ASSEMbliES
3RT, 3RH Contactors for Special Applications
Contactors with Extended Operating Range 0.7 ... 1.25 x , for Railway Applications
3RT20 motor contactors, 7.5 ... 25 HP
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SIRIUS Innovations Supplement 2012
3
Overview
DC operation
IEC 60947-4-1, EN 60947-4-1,
for requirements according to IEC 60077-1 and IEC 60077-2.
The contactors are finger-safe according to EN 50274. The
contactors have spring-type connections as well as screw
connections. The size S00 and S0 contactors have spring-type
connections for all terminals.
Ambient temperature
The permissible ambient temperature for operation of the con-
tactors (across the full coil operating range) is -40 to +70 °C.
Uninterrupted duty at temperatures > +60 °C reduces the
mechanical endurance, the current carrying capacity of the
conducting paths and the switching frequency.
Control and auxiliary circuits
The solenoid coils of the contactor relays have an extended coil
operating range from 0.7 to 1.25 or 1.3 x U
s
and are fitted as
standard with suppressor diodes. The opening delay is
consequently 2 to 5 ms longer than for standard contactors.
Application
For operation in installations which are subject both to
considerable variations in the control voltage and to high
ambient temperatures, e. g. railway applications under extreme
climatic conditions, rolling mills, etc.
Also for control supply voltages with battery buffer for longer
operating times should the battery charging fail.
Contactors without series resistor
Control and auxiliary circuits
These contactors have an extended operating range from
0.7 to 1.25 x U
s
; on size S00 the coils are fitted with suppressor
diodes, on size S0 with varistors. An additional series resistor is
not required.
Note:
An additional auxiliary switch block cannot be mounted.
Side-by-side mounting
A clearance of 10 mm is required for side-by-side mounting at
ambient temperatures > 60 °C
≤ 70 °C.
3RT20 1. contactors with series resistor
Control and auxiliary circuits
The solenoid coils of the contactors have an extended coil oper-
ating range from 0.7 to 1.25 x U
s
and are fitted as standard with
suppressor diodes to provide protection against overvoltage.
The DC solenoid systems of the contactors are modified (to
holding excitation) by means of a series resistor.
The size S00 contactors are supplied prewired with a plug-on
module containing the series resistor. The suppressor diode is
integrated. A 4-pole auxiliary switch block (according to
EN 50005) can be fitted additionally.
A circuit diagram showing the terminals is labeled on each con-
tactor. One NC of the auxiliary contacts is required for the series
resistor function. The selection and ordering data shows the
number of additional, unassigned auxiliary contacts. With size
S00 it is possible to extend the number of auxiliary contacts.
Side-by-side mounting
At ambient temperatures up to 70 °C, the size S00 contactors
and contactor relays are allowed to be mounted side by side.
3RT20 2. contactors with solid-state operating mechanism,
extended operating range
Control and auxiliary circuits
The solenoid coils of the contactors have an extended coil oper-
ating range from 0.7 to 1.3 x U
s
and are fitted as standard with
varistors to provide protection against overvoltage.
The contactors are energized via upstream control electronics
which ensure the coil operating range of 0.7 to 1.3 x U
s
at an
ambient temperature of 70 °C. They are supplied as complete
units with integrated coil electronics. A varistor is integrated for
damping opening surges in the coil.
The mounting possibilities for auxiliary switches correspond to
those of the standard contactors for switching motors in the
matching size (see page 3/6).
Side-by-side mounting
Side-by-side mounting is permitted at ambient temperatures up
to 70 °C for these contactor versions in size S0.
6/T3
5/L3
4/T2
3/L2
2/T1
1/L1
E1+
Q1
Q1
A2-
NSB0_02178
R
S1
L-
L+
v
U
s
LV1N_03_06.fm Page 55 Thursday, October 31, 2013 11:31 AM
(see page 2/58).
Contactors and Contactor Assemblies
3RT, 3RH Contactors for Special Applications
3RT20 motor contactors, 7.5 ... 25 HP
Product Category IEC