Figure 3-21.Relay contact arrangement.
One type of relay with multiple sets of contacts is the clapper relay shown in figure 3-22. As the
circuit is energized, the clapper is pulled to the magnetic coil. This physical movement of the armature of
the clapper forces the pushrod and movable contacts upward. Any number of sets of contacts may be built
onto the relay; thus, it is possible to control many different circuits at the same time. This type of relay
can be a source of trouble because the motion of the clapper armature does not necessarily assure
movement of all the movable contacts. Referring to figure 3-22, if the pushrod were broken, the clapper
armature might push the lower movable contact upward but not move the upper movable contact.
Figure 3-22.Clapper-type relay.