The switching components are normally used to activate and deactivate the motor in a safe manner, that is, without any contact of the operator in the power circuit in which the greater current flows. It should be emphasized that in the analysis of electrical controls it is extremely necessary to make sure that they have the proper sequence, which will serve as the basic orientation for the design of any circuit. One of the points considered fundamental to the understanding of electrical commands is the understanding that the main functions of the elements when it comes to an electrical panel are to protect and preserve the operator and to provide a command logic.
Based on the principle of operator protection, a generic sequence of the essential elements at the start and also the engine maneuvers. In these maneuvers can be highlighted the following elements, the sectioning, that can be operated only without load. It is used during the circuit maintenance and verification process. The protection against short-circuit currents is intended to protect the terminal circuit conductors and the protection against overcurrent currents acts in order to protect the winding coils of the motor.