EI66 50VA Single Phase Low Frequency Power Transformer Control Transformer for Industrial Machinery and Electrical Equipment EI66 50VA single-phase low frequency control transformer adopts EI silicon steel core structure, designed for 50/60Hz mains frequency. It realizes AC voltage conversion and galvanic isolation, rated capacity 50VA. It is widely used as control power supply for industrial machinery and electrical equipment. Custom input & output voltage, winding and lead