| 摘要 |
PROBLEM TO BE SOLVED: To verify interface insulation easily and simply without impressing higher voltage than voltage to ground by impressing antiphase power of 50% of fixed power on power conductors of the other two phases, when fixed voltage is impressed on a power conductor of one phase of a three-phase package electrical machinery and apparatus. SOLUTION: Fixed voltage V is generated between the terminals U-E on the secondary side of a transformer 1 for testing the single phase. At this time, because voltage V/2 is generated between the terminals V-E on the secondary side, and the exciting direction of a coil is reverse, it becomes voltage of different phase by 180 degrees. Then the voltage V of the U-terminal is impressed on the R-phase impressed terminal 3a of a three-phase batch electrical machinery and apparatus 2 through an impressing line 4a, simultaneously with it, the voltage V/2 of the V-terminal is respectively impressed on a S-phase impressed terminal 3b and a T-phase impressed terminal 3c through an impressing line 4b. Hereby, the voltage V is impressed between the terminal 3a and the chest of the machinery and apparatus 2, the voltage V/2 of antiphase is impressed between the terminals 3b, 3c and the chest, and voltage V+(-V/2) is impressed between the terminal 3a and the terminals 3b, 3c.
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