NEIEP Mechanics Practice Exam

In what scenario would a generator field be de-energized?

1. During regular operation

2. When starting the generator

3. During a fault condition

4. When shutting down

The correct answer is: When shutting down

A generator field would be de-energized during the shutdown process. This is an important safety protocol in the operation and maintenance of generators. When a generator is being shut down, the field winding, which is responsible for creating the magnetic field necessary for generating electricity, is de-energized to safely halt operations. De-energizing the field prevents any potential back feed of voltage which could damage equipment and ensure that residual energy is safely dissipated. This action is typically performed after the load has been disconnected and before other shutdown procedures take place, ensuring that the generator stabilizes without generating excess power. During regular operation, the field is energized to allow the generator to produce electricity. When starting the generator, the field may need to be energized to establish the necessary magnetic field for operation. In fault conditions, the system might employ protective measures that can include de-energizing the field to safeguard against damage, but this isn't a standard procedure like during shutdown. Thus, the most common and systematic action in a shutdown scenario is the de-energizing of the generator field.