In a motor starter, how is the seal-in auxiliary connected with the start button?

The correct approach is to connect the seal-in auxiliary in parallel with the start button. This configuration allows the control circuit to remain energized even after the start button is released, which is a key aspect of how a motor starter operates.

When the start button is pressed, it allows current to flow through the circuit, energizing the coil of the starter. At the same time, the seal-in auxiliary contact, which is part of the starter, closes and creates a parallel path around the start button. Once the button is released, the closure of this auxiliary contact keeps the coil energized, allowing the motor to run continuously until it is stopped by opening the circuit, typically via a stop button or other mechanism.

Using a parallel connection for the seal-in auxiliary ensures that the control circuit stays closed and maintains operation of the motor after the initial command is given, which is crucial for automated processes in industrial settings. The other options, while they may describe connections used in different contexts, do not facilitate the required functionality of maintaining circuit continuity after the initial activation.