Auxiliary Contactors

An auxiliary contactor is a coil-operated contactor type that has NO and NC contacts carrying only control current instead of power contacts and is used to multiply signals in the control circuit. It is found in automation and motor control panels to distribute one signal to several circuits, build interlocking and latching circuits, and act as an intermediate element between a PLC output and a contactor coil. The category includes the Schneider Electric TeSys Deca (CAD), TeSys K (CA2K) and EasyPact TVS (CAE), ABB NF and NFZ, and Siemens 3RH2 series; contact arrangements such as 4NO, 3NO1NC, 2NO2NC, 3NO2NC and 5NO and coil voltages such as 24 V DC, 24 V AC, 110 V AC and 220 V AC are examples. Choose the required number of NO and NC contacts, the coil voltage and AC/DC type, and the need for an additional contact block according to your control diagram. In the ABB NF series, the two digits in the model code show the number of NO and NC contacts; for example, the NF31E has three NO and one NC contacts. An auxiliary contactor is not designed to switch power loads such as motors or heaters; it does not replace a power contactor.

Products

How to choose Auxiliary Contactors

An auxiliary contactor is a coil-operated contactor type that has NO and NC contacts carrying only control current instead of power contacts and is used to multiply signals in the control circuit. It is found in automation and motor control panels to distribute one signal to several circuits, build interlocking and latching circuits, and act as an intermediate element between a PLC output and a contactor coil.

  • Separate overcurrent/leakage protection, motor starting and local isolation requirements.
  • Select rated current, pole count and breaking capacity (kA) from the installation calculation.
  • Match coil voltage, auxiliary contacts and tripping curve to the control circuit and load type.

Frequently asked questions

What is Auxiliary Contactors and where is it used?

An auxiliary contactor is a coil-operated contactor type that has NO and NC contacts carrying only control current instead of power contacts and is used to multiply signals in the control circuit. It is found in automation and motor control panels to distribute one signal to several circuits, build interlocking and latching circuits, and act as an intermediate element between a PLC output and a contactor coil.

What should I compare when choosing Auxiliary Contactors?

Choose the required number of NO and NC contacts, the coil voltage and AC/DC type, and the need for an additional contact block according to your control diagram.

Where can I find technical details for Auxiliary Contactors products?

An auxiliary contactor is a coil-operated contactor type that has NO and NC contacts carrying only control current instead of power contacts and is used to multiply signals in the control circuit.

Auxiliary Contactors Selection Guide: Technical Criteria and Engineering Practice