5300, 5400, 5500 Transformers Murata Power Solutions 5300, 5400, 5500 Transformers are current sense transformers designed to monitor AC currents. Murata Power Solutions 5300, 5400, 5500 Transformers can be used for high-frequency current sensing in applications such as switched-mode power supplies, motor control, and electronic lighting ballasts. Transformers in these series are available in 20, 50, 100, and 200 turn variants, including those with industry-standard or compact footprints.