What is a seal-in switch used for?

A seal-in switch is utilized to maintain current flow after an initial action has been taken, such as the activation of a control circuit. When the control device is energized, the seal-in function allows the circuit to remain closed even after the initial signal is removed, ensuring that the power remains on. This is particularly important in control systems where continuous operation is needed even if the triggering device, like a pushbutton switch, is released.

In applications where a brief action is needed to engage a device—like starting a motor—the seal-in switch provides a mechanism to keep that device running without requiring the operator to continually hold the control action. This is essential in many electrical systems for automation and safety.

Notably, other options do not accurately describe the function of a seal-in switch, as they relate to disconnecting power, limiting current, or enhancing contactor performance rather than maintaining established current flow after activation.