SIEMENS
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Siemens IC 10 · 2017
Contactors for Special Applications
Contactors for Railway Applications
3TC contactors for switching DC voltage, 2-pole
4
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Overview
Standards
IEC 60947-4-1, EN 60947-4-1
The contactors are finger-safe according to IEC 60529 (excep-
tion: series resistor). Terminal covers may have to be fitted onto
the connecting bars, depending on the configuration with other
devices.
All specifications and technical specifications not mentioned
here are identical to those of the standard 3TC contactors,
see page 4/75
.
Ambient temperature
The permissible ambient temperature for operation of the con-
tactors (across the full coil operating range) is -50 to +70 °C. Un-
interrupted duty at temperatures <
-25
°C and >
+55 °C reduces
the mechanical endurance, the current carrying capacity of the
conducting paths and the switching frequency.
At ambient temperatures > 55 °C, a clearance of 10 mm is
required for side-by-side mounting of size 2 contactors.
There is no need to reduce the technical specifications.
Ratings of three-phase motors
The quoted rating (in kW) refers to the output power on the motor
shaft (according to the nameplate).
The power rating specifications of the contactors in kW are
guide values for 4-pole standard motors at 50 Hz AC and spec-
ified voltage (e.g. 400 V). The actual starting and rated data of
the motor to be switched must be considered when selecting the
units.
Series resistor
The DC solenoid systems of the 3TC contactors must be modi-
fied (to hold-in coil) by means of a series resistor. This series
resistor is supplied separately packed with the contactors.
With types 3TC48, the series resistor must be attached onto the
right-hand side of the auxiliary switch block by means of the
enclosed mounting parts and sets of links provided, while in the
case of the 3TC44 it must be mounted and wired between the
contactor poles. With types 3TC52 and 3TC56, the series
resistor must be attached separately next to the contactors.
Auxiliary contacts
The contactors are equipped with two lateral auxiliary switch
blocks each with 1 NO + 1 NC contact. Further auxiliary switch
blocks cannot be fitted to the DC-operated contactors.
One NC contact is required for the series resistor function.
Two NO contacts and one NC contact are thus freely available.
Reversing contactors
With the 3TC52 and 3TC56 contactors, the series resistor must
be connected using an additional K2 reversing contactor
(3RT1317-1F.40). This contactor is automatically included in the
scope of supply in the same packaging as the contactor.
Dimensions
Attaching resistors and varistors increases the width of the
contactors.
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Application
For operation in installations which are subject both to consider-
able variations in the control voltage and to high ambient
temperatures, e.g. in railway applications.
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
varistors to provide protection against overvoltage. The opening
delay is consequently 2 to 5 ms longer than for standard contac-
tors.
■
Technical specifications
All details and technical specifications not mentioned here are
identical to those of the basic units of the 3TC contactors,
see page 4/75
.
More information
Technical specifications,
see
Manuals,
see
Type
3TC44
3TC48
3TC52
3TC56
Size
2
4
8
12
General data
Ambient temperature
• During operation
°C
-40 ... +70
Control
Solenoid coil
operating range
0.7 ... 1.25 x
U
s
Power consumption of the solenoid coils
For cold coil and 1.0 x
U
s
• Closing
W
48
26
40
130
• Closed
W
13
14
21
59
© Siemens AG 2016