The Helios ESD 11.5 is a high-performance, stepless electronic transformer controller designed for regulating three-phase fans via voltage reduction. Utilizing advanced microcontroller technology, it supports control through a 0 – 10 V analog input or an electronic temperature controller such as the EKW 6.3. Multiple ESD units can be operated in parallel, enabling flexible management of ventilation across several fans or systems. Built-in protection monitors motor thermal contacts to prevent overload. The controller complies with EMC Class B standards and does not require shielded cabling between the unit and motor.