If a reverse current cutout relay fails to open, how will current flow through the generator armature?

When a reverse current cutout relay fails to open, it allows for a reverse current to flow in the generator armature. In this scenario, the current does not only flow in the normal direction from the generator to the load but can also flow back toward the battery. This backward flow occurs while simultaneously allowing the current to continue passing through the shunt field in the normal direction.

The reverse current cutout relay serves the critical function of preventing the battery from discharging back through the generator when the generator voltage drops below the battery voltage. If the relay fails to open, both forward and reverse current paths can exist simultaneously. This unique situation highlights the relationship and interaction between the generator's armature and the shunt field windings, which is essential for the proper functioning of the generator.

Therefore, current can indeed flow in the opposite direction through the armature while still energizing the shunt field in the normal forward direction, allowing it to maintain its magnetic field but also potentially leading to inefficient operation or battery discharge, which underscores the importance of the relay's operation.