It is valid to note that the numbering of the auxiliary contacts must follow the following pattern, one and two being the normally closed contacts, NF, with 1 being the input and 2 being the output. And three and four are the normally open contacts, NA, with 3 being the input and 4 being the output. https://www.mrosupply.com/motors/ac-motors/general-purpose-motors/24486_em3714t_baldor/ In the relays and contactors have A1 and A2 for the coil terminals. Thus, the auxiliary contacts of a contactor must follow a specific type of numbering, since the number is composed of two digits, the first digit indicates the number of the contact and the second digit indicates if the contact is of the type normally closed, one and two, or normally open, three and four.
Therefore, in the same way that each element and device found in an electric control circuit present a specific graphic symbology, the numbering of the contacts, as well as the literal representation of them also has a standard that must be respected and followed. The numbering of the contacts representing the power terminals is duly presented as follows, one, three and five are of the input circuit, line. The two, four and six are from the output circuit in the terminal.