Relays are used for miscellaneous purposes and are named according to the purpose they
serve. They are basically alike in construction and operation. Two of the most common are the ground
relay and the wheel slip relay.
(1) Ground relay. Illustrated in figure 1.18, a ground relay is installed in the main power
circuit to warn if a ground develops. When the circuit is grounded, current flows through the relay and
its contacts close circuits to an alarm bell or an indicator
1 Ground relay cutout switch
2 Reset button
Figure 1.18. Ground Relay.