What is a characteristic of the main contacts in a reversing starter during a change of direction?

In a reversing starter, the main contacts play a critical role during a change of direction of an electric motor. When the direction is changed, it is essential to disconnect the power supply to the motor. This momentary power interruption is crucial to prevent the motor from stalling or getting damaged due to mechanical stress from the sudden change in direction.

By disconnecting the power supply, the starter ensures that the motor can safely switch its rotation without causing any damage or overload to the system. This characteristic helps maintain system safety and operational integrity when switching the motor's direction.

The other options do not accurately represent the behavior of the contacts in a reversing starter during this operation. For instance, the contacts do not remain closed during a direction change; doing so would create a short circuit or damage the motor. Engaging separate protective circuits is not a primary function of the main contacts in this context, and interconnecting alternating power sources does not relate to the typical operation of a reversing starter when changing direction.