| 摘要 |
PURPOSE:To prevent the rise of the voltage on the other terminal line even in case of the ground-fault of one terminal line, by providing resistances having the same value in one ends of the first secondary winding and the second secondary winding of a transformer, and grounding them. CONSTITUTION:If the circuit is short-circuited between points (c) and (d) is Fig., the voltage between a line 1 and the earth is reduced to 0V. At this time, no resistance components appear as an impedance Za viewed from a secondary winding n2 of the transformer, and a load Z appears as an impedance Zb viewed from a secondary winding n3. Consequently, Za<=Zb is obtained between impedances Za and Zb. Therefore, A value I2 of the current flowed to the secondary winding n2 is equal to or larger than a value I3 of the current flowed to the secondary winding n3, and the current is hardly flowed to the secondary winding n3 of a transformer T. Consequently, the voltage between a line 2 and the earth is lowered to a voltage -V2 near zero. |
