Electromechanical elementary relays

They are of two types:

• Type A: relay in which all contacts are mechanically linked (or Forcibly guided).
• Type B: relay containing contacts that are mechanically linked to each other as well as contacts that are not mechanically linked.

They also have two parts only:

• The control part: it is the coil that moves the auxiliary contacts. The terminals are indicated as “A1” and “A2”.
• The Auxiliary contacts: some are normally open and some are normally closed.

Type A relays with forcibly guided (mechanically linked) contacts are marked either with the words “type A” or with the symbol shown in the Figure below.

Type B relays with forcibly guided (mechanically linked) contacts are marked either with the words “type B” or with the symbols given in the Figure 4.34 {4.12.2.3.4} below.