A power converter circuit (3) drives a switching device by the pulse-width modulated wave for converting a direct current into the three phase alternating current.

电力变换器主电路部（3），其根据该脉冲宽度调制波对 开关元件进行驱动，将直流电压转换为三相交流电压；

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The test on three phase alternating voltage has shown that this system has good reliable performances and can afford evidence for finalizing the design of power supply system made in our country.

通过对三相交流电压的测试试验，验证了该系统的可靠性，可为国产电源系统的设计定型提供依据。

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A three-phase alternating current parameters instrument to be used in industry is designed. It can measure the voltages, currents, power factors of each phase of three-phase alternating current.

设计开发一种工业用三相交流电参数仪，能够测得三相交流电各相的电压、电流、功率、功率因子等参数；

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Although they have not been found to cause any harm, the cables on conventional pylons, which transmit a three-phase alternating current, generate a strong electric field and a continuous buzz of low-frequency radio waves.

ECONOMIST: Monitor