What is the primary purpose of a seal-in circuit?

The primary purpose of a seal-in circuit, also known as a holding circuit, is to maintain the relay energized after the initial activation. When a relay is engaged (usually through a momentary pushbutton), it closes its contacts and allows current to flow through the seal-in circuit. This current path remains closed, keeping the relay energized even after the pushbutton is released. This is crucial for various applications where continuous operation is needed after an initial start command.

The design of the seal-in circuit ensures that once the system is activated, it remains operational without needing constant input. This characteristic is essential in electric motor control systems, where maintaining the state of the relay allows for smoother operation and control of motors and other connected devices.

In contrast to the other choices, the correct option focuses on maintaining the operational status of the relay rather than providing power to the relay itself initially, cutting power, or simply providing feedback. Each of those aspects can serve other functions in an electrical control system but does not capture the essence of what a seal-in circuit specifically aims to achieve.