| 摘要 |
PURPOSE:To prevent the distortion of current waveform of other phase in the non-current period occurring when the monophase thyrister is changed over, by connecting the neutral point of the secondary winding of a winding type induction machine to a frequency converter. CONSTITUTION:A collecting collar 4N of a winding type induction motor 1' is connected to the neutral point 0 of a secondary winding and also to a fre quency converter 5'. The frequency converter 5' is equipped with a thyrister to control the current of N phase through the neutral point O and the collecting collar 4N. The current each between U-N, V-N and W-N is controlled independently. Consequently, e.g. in the non-current period when the U-phase current is changed over from positive to negative and vice versa, the current between the V-phase-N-phase and W-phase-N-phase is independently controlled and is flown through the neutral point O and the collecting collar 4N. Thus, the occurrence of distortion of current in V-phase or in W-phase can be prevented. |
