Motor Starting with Capacitors

A portion of the high-inrush incident to starting of large synchronous motors can be supplied by static capacitors because of the low power factor of the inrush kVA. However, care must be exercised in application of the static capacitors so as to avoid harmful resonant conditions, overvoltage due to self excitation of the motor and the proper selection or sizing of equipment for a specific application. An installation in a cement plant of large synchronous grinding mill motors employing static capacitors for motor starting is reviewed. Some of the considerations in application are shown and results of operation are also shown.