Auxiliary contacts are important elements of control and automation systems. They are used both in industry and in home control systems, providing control over the flow of current and control signals between individual elements of the system. How do they work? What industrial applications are they used for? What types do we distinguish? We write about this in a new article.
Check the auxiliary contacts at the Onninen wholesaler
The role of the auxiliary contactor in electrical circuits
The principle of operation of auxiliary contacts is similar to that of elements such as connecting strips and main contacts. They conduct current by connecting several wires, but they allow control of the operation of a given system. The current affects the electromagnet coil, which causes a specific reaction - opening or closing the electrical circuit. This allows control of the operation of various devices and signaling of operating states or occurrence of disturbances, which is a guarantee that the system will be stable and the entire electrical equipment - safe and efficient.
Depending on the specifics of a given system and the role that the contact is to play, users can choose one of the following variants of this device:
- NO (Normally Open) : conducts electricity when the circuit is closed (in the rest state the circuit is open);
- NC (Normally Closed) : the circuit is closed when idle and opens when activated;
- switchable : allow switching between circuits. Depending on the configuration, they can operate as NO or NC.
Application of auxiliary contactors in industrial automation
Auxiliary contacts are used primarily in industrial automation. In systems of this type, they are responsible for controlling machines and production devices. They make it possible to automate individual processes and control machine operating parameters. Signals transmitted by these contacts can also signal the occurrence of disturbances, informing about the need for intervention and increasing the level of safety in the plant.
Practical applications of auxiliary contacts include automatic starting of machines, control of safety circuits and control of lighting and heating systems. This is possible thanks to the numerous advantages that this type of product has. The most important are:
- reliability : in a well-designed and manufactured system, the contacts can operate without failure for many years, ensuring the stability of the entire system. Housings made of insulating plastic materials effectively protect them against dust, moisture and other external factors;
- universality : individual contact models differ, among others, in terms of parameters of permissible voltage, power and construction. This makes it easier to adapt them to the specifics of a given application;
- Ease of installation and maintenance : auxiliary contacts are easy to install and many models allow for series mounting.
Types of auxiliary contacts
In addition to the aforementioned mode of operation (NO, NC and changeover), the criterion for dividing auxiliary contacts is also the design and type of installation in the system. In this respect, we distinguish two types:
- front contacts : designed for mounting on contactors from above. This does not increase the width of the contactor (but the height of the set increases);
- side contacts : mounted on the right or left side of the contactor. In their case, the width of the set changes, but the height remains the same. Like some front contacts, selected models of side contacts can be built on top of each other.
Thanks to a wide selection of models and their functions, auxiliary contacts are used in many industries. In automation systems, they ensure the safety and efficiency of various devices.