3TK2804 PDF Datasheet – Contactor Safety Combination

Part Number: 3TK2804

Function: Contactor Safety Combination

Package: Module type

Manufacturer: Siemens


2 page
siemens 3TK2804 datasheet


The 3TK2804 is contactor. This is an electrical switching device used to control and switch electrical power circuits. It is typically used in applications where a high current load needs to be controlled by a lower current control signal. Contactors are commonly found in industrial and commercial electrical systems and play a crucial role in the operation of various machinery and equipment.

1. Capacity and Switching Capability:

(1) Contactors: Primarily used in high-power applications. Contactors are suitable for switching and controlling high current and voltage circuits, such as large motors, pumps, and compressors.

(2) Relays: Mainly used in low-power and medium-voltage applications. Relays are suitable for switching and controlling small current and voltage levels, isolating signal interference, or detecting control signals.

2. Size and Form Factor:

(1) Contactors: Larger in size and typically installed on DIN rails or within electrical panels.

(2) Relays: Available in various sizes and shapes, ranging from small to large form factors.

3. Types and Applications:

(1) Contactors: Mainly used in industrial and commercial settings to control power to large machinery and equipment.

(2) Relays: Primarily used in control systems and automation applications for signal processing, detection, and control.

The internal control circuit of the contactor safety combination is designed according to DIN EN 60204, Part 1 (VDE 0113, Part 1), para., so that in the case of a fault in one of the contactor relays the function of the safety circuit is maintained. The supply voltage must meet the requirements of the DIN EN 60204 (VDE 0113, Part 1) (the terminals “L-/N; A2“ must be connected to that side of the control current circuit which is linked to the protective conductor system).The contacts of the contactor relays are checked for proper opening and closing in every ON and OFF cycle of the machine to be switched.

This is, for instance, done by

– connecting and disconnecting the control voltage with the main switch,

– activating and deactivating the EMERGENCY-OFF unit

– opening and closing of the protective screen.

The contactor safety combinations can be used in EMERGENCY-OFF circuits and for monitoring protective devices (e.g. protective screens).


3 page
3TK2804 pdf manual


1. The contactor safety combinations can be used in EMERGENCY-OFF circuits and for monitoring protective devices (e.g. protective screens).

Other data sheets are available within the file: 3TK2803, 3TK2907

3TK2804 PDF Datasheet

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