Patent ID: 6339309
Filing Date: 2002-01-15
Classification: H02P

Abstract:
An apparatus for switching an AC motor between two power supplies having instantaneous voltage differences, comprisinga first switch mechanism adapted to be coupled to a first power supply and a motor to selectively couple the motor to the first power supply; a second switch mechanism adapted to be coupled to a second power supply and the motor to selectively couple the motor to the second power supply; a current detector adapted to be coupled to the first power supply to monitor output current of the first power supply; and a controller coupled to said first switch mechanism and said second switch mechanism and configured to control the status of said first switch mechanism and said second switch mechanism, with said first switch mechanism in a closed state and said second switch mechanism in an open state to allow the motor to run under power from the first power supply, said controller is operative to close said second switch mechanism in response to a transfer signal and subsequently place the first power supply in a idle mode when said current detector indicates that an instantaneous current in the output of the first power supply changes by a predetermined current amount to transfer the motor to run under power from the second power supply.