AC MOTOR WITH STATOR WINDING TAP AND METHODS FOR STARTING AN AC MOTOR WITH A VARIABLE SPEED DRIVE

摘要

Methods for starting an AC motor with a variable speed drive and switching the motor to a higher voltage power source are described. Provided are AC motors with a stator having a plurality of coils, the plurality comprising a complete set of coils for each phase, the complete set comprising a first set of coils comprising first groups of coils connected in series, or parallel, or a combination, and a second set of coils comprising second groups of coils connected in series, or parallel, or a combination, wherein the output of a variable speed drive is connected to a tap on the complete set of coils such that the AC motor may be started with a variable speed drive, and an output of the power line is connected to the series of the first and second sets of coils.

主权项

1. An AC motor starting method, comprising:
(a) providing power from a variable speed drive to an AC motor comprising: a stator winding with an arrangement of coils per phase; each of the arrangements of coils per phase comprises n subsets of coils, wherein n is the number of poles on the stator; each subset of coils comprises a first group of coils and a second group of coils, where the first groups of coils are connected to form a first set of coils and where the second groups of coils are connected to form a second set of coils; each subset of coils is configured such that the first group of coils is symmetrically disposed relative to a center of the subset and such that the second group of coils is symmetrically disposed relative to the first group of coils; a first end of the second set of coils is in operable connection with a power line; a second end of the second set of coils is connected in series to a first end of the first set of coils; a second end of the first set of coils is connected to a neutral point inside the AC motor; a tap is connected to the point where the first and second sets of coils are connected in series and is in operable connection with a variable speed drive; (b) accelerating the AC motor to maximum speed using the variable speed drive; (c) switching to the power line from the variable speed drive as a power source and continuing to provide power to the AC motor.