The Helios MD is a combined relay switch and protection unit designed for use with fans equipped with built-in thermal contacts. Housed in a durable polymer enclosure, it can be surface-mounted or integrated into a control cabinet using terminal strip fixation. The unit allows on/off operation via a push-button switch and provides full motor protection. In the event of a fault, the system requires a manual restart, ensuring safe and controlled reactivation. This accessory is ideal for enhancing operational safety and reliability in ventilation systems