| 摘要 |
PURPOSE:To make a voltage cancelling a voltage which is induced by the floating impedance of an electromagnetic power application machine connected to an AC power supply induced in the secondary side of a transformer by a method wherein an impedance equivalent to the floating impedance is provided on the primary side of the transformer which is connected to the AC power supply through the equivalent impedance. CONSTITUTION:An equivalent impedance 3 is connected to one of the terminals of the primary side of a transformer 2 and connected to one 10 of the power supply lines 10 and 11 through the equivalent impedance 3 while the other terminal is connected to other power line 11. The phase of the secondary side of the transformer 2 is reversed and the one of the terminals of the primary side is connected to the grounding point 32 of a machine 30 and the other terminal is connected to the grounding line 4. A voltage which is approximately equivalent to a voltage induced by a floating impedance 31 in the machine 30 is applied to the primary side of the transformer 2 by the equivalent impedance 3 and a secondary voltage corresponding to the turn ratio of the transformer 2 is induced. At that time, the phase of the voltage induced by the floating impedance 31 is opposite to the phase of the secondary voltage of the transformer and the two voltages cancel each other and a current through the grounding line 4 is eliminated. With this constitution, the erasing circuit of an electromagnetic power application machine can be obtained asa small and simple apparatus. |
