Final answer:
When a motor starter coil is de-energized, the contacts open due to gravity and spring tension, breaking the circuit and stopping the motor from receiving current.
Step-by-step explanation:
When a motor starter coil is de-energized, the contacts typically open due to gravity and spring tension. This ensures that the circuit is broken and the motor stops receiving current. The contacts do not stay closed; they are not held closed mechanically in a de-energized state, and they do not need time to cool for a restart unless otherwise designed for a specific application. Electric motors operate on principles of electromagnetic force, where a magnetic force acts on the current-carrying coils within the motor, thereby inducing rotation. When the motor is running, an opposing voltage known as back electromotive force (emf) develops, which helps regulate the current draw of the motor.