The series consists of three VRT devices specially developed for the control of electric motors, particularly those fitted to the ventilation systems, able to diagnose motor faults by evaluating changes in current drawn by the same. Protection and operation of ventilation systems for cast resin transformers are integrated in one device. VRT200: basic model with 2 outputs, able to drive 3 fans each All units are equipped with leds for visual anomalies indication and FAULT relay for signal anomalies. Fans can be driven remotely (dry contact input) or “locally” via the front push button.