Industrial automation

 Long Baoying role in the drive

  The main circuit of the inverter has been generally pay a cross composed of external input 380V/50Hz frequency power through a three-phase bridge rectifier to a DC voltage is not controlled by capacitor filter and power transistor switching element is a variable frequency inverter AC voltage. In the rectifier circuit, the input current waveform is irregular rectangular wave, waveform by Fourier series decomposition of the fundamental and harmonics, harmonic number is usually 6n ± 1 times higher harmonics, which are higher harmonics wave will interfere with the input power supply system. Need to install the input reactor. The impact of the motor inverter output harmonic: motor attached additional heating of the motor temperature; produce mechanical vibration, noise and over-current. Harmonic drive will power capacitors overload, overheating and even damage the capacitors. When the capacitor reaches resonance vibration with the line impedance, short circuit, over current and noise will occur. Harmonic currents cause the inverter switching device in the startup instantly generate high current rate of change. Need to install the output reactor

 

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