Being the common

摘要

PROBLEM TO BE SOLVED: To provide a common mode transformer facilitating mounting and achieving a reduction in cost.SOLUTION: In the common mode transformer, voltages generated on power lines (3a-3c), corresponding to a common mode voltage, are input to a primary winding (91), and voltages generated on secondary windings (92-94) are superimposed as canceling voltages on the common mode voltages generated on the power lines (3a-3c). The common mode transformer includes a first core part (95A) that is helical, and a second core part (95B) provided between one end and another end of the first core part (95A). A primary winding (91) is wound around the second core part (95B), and the power lines (3a-3c) penetrate the first core part (95A). Portions of the first core part (95A) which are penetrated by the power lines (3a-3c) are used as secondary windings (92-94).