| 摘要 |
PURPOSE:To demagnetize the residual magnetism of the induction electric equipment safely in a short time, by generating a damped oscillation of a resonant frequency in the series circuit of a winding and a capacitor in the induction electric equipment. CONSTITUTION:The capacitor Co has electrostatic capacity, by which the resonant frequency of the series circuit of a reactance L of a transformer Tr1 and the capacitor becomes sufficiently lower than a commercial frequency. A power source switch SW1 is closed, and a DC i0 is conducted through the secondary winding of the transformer Tr1 through a resistor r from a power source BA so that the current becomes equal to or larger than the saturating current of the transformer Tr1 and it is excited by the DC. When the switch SW1 is opened, the damped oscillation current i1 is generated in the series circuit of the reactance L of the transformer Tr1 and the capacitor C0. The residual magnetism in the core of the transformer Tr1 is demagnetized by the flowing of the damped oscillating current i1 based on the current i0 in the transformer Tr1. |
