The harmonic problems, such as distorting supply voltage, decreasing power factor, increasing energy loss, interfering with communication systems etc. are discussed in the part one.
第一部分讨论各种谐波问题，如使供电电压畸变，降低功率因数，增加能量损耗，干扰通讯系统等。
2
Speed regulation system using cascade control method with thyristor is a low-cost system, but the classic system has some shortages, such as low power factor, serious harmonic pollution and etc.