Start-up Technique of Medium-voltage Motor

It is known that when directly starting up the medium-voltage motor under the rated voltage, there comes high current which may negatively influence the stability of the electric network, and in turn, cause abnormal operation of other equipment units sharing the same network. Several methods for motor-starting and some new foreign-developed techniques for motor starting and medium-voltage transformation/regulation are introduced here in the article. It is pointed out that although it is rather expensive, the medium-voltage inverter is worth using for starting-up of the medium-voltage motor owing to the fact that it satisfies such requirements as soft start-up, frequently start-up as well as no impulse onto the electric network.