The auxiliary contacts of a contactor adopt a specific type of numbering, since the number is combined by two digits, the first digit indicating the contact number and the second digit indicating whether the contact is normally closed, one two, or normally open, three and four.
Just as each element contained in an electric control circuit has its specific graphic symbol, the numbering of the contacts and the literal representation of them also have a pattern that must be respected and followed. 2B5V64
The numbering of the contacts representing the force terminals is given as follows, one, three and five are the input circuit, line. The two, four and six are from the output circuit in the terminal. The number of the auxiliary contacts follows the following pattern: one and two are 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 entrance and 4 being the exit. In the relays and contactors there are A1 and A2 for the coil terminals.