It is necessary to know the basic components of electric circuit circuits and their purposes. The seal is intended to keep current flowing through the contactor, even after the operator has removed the finger from the button. The seal with two contacts exists for better security in the system, and two seal contacts can be used. Interlocking is the process of connecting auxiliary contacts from multiple devices. The circuit parallel to the interlocking that should not create a parallel circuit and the interlocking with two contacts https://www.mrosupply.com/popular_products/motor-frame-sizes/ where two interlocking contacts, connected in series, increase the safety of the system.
In Conditioned Connection a NO contact of contactor K2 before contactor K1 means that K1 can be operated only when K2 is closed. The operation of one is conditioned to the other. When protecting the system, the auxiliary contacts of the overload protection relays and the shut-off buttons must always be in series, in the interlocking with buttons it is recommended that one of the buttons be indicated with your inverted contacts.
In the multi-wire scheme the arrangement of the elements of the circuit can be any one, with the advantage that they are easily recognized and in the Functional scheme the system is subdivided according to the existing circuits of currents. They should be represented, where possible, by straight lines, free of crosses.