The Helios TSD 1.5 is a speed controller designed to regulate one or more 3‑phase fans through voltage reduction. It provides selectable voltage options of 0, 80, 140, 280, and 400 volts to customize fan speeds effectively. Encased in a housing with an IP54 rating, it offers protection against dust and water spray and operates on a frequency of 50/60 Hz. This device delivers flexible and reliable fan speed management for ventilation systems.