Patent ID: 8384337

Claim:
A conveyor system, comprising: a conveyor; an electric motor to move the conveyor; a voltage determining device adapted to be coupled to an alternating-electricity source that supplies alternating electricity to the conveyor system; a power supply apparatus to supply power between the electric motor and the alternating-electricity source of the conveyor system, the power supply apparatus comprising: an inverter, the inverter including a rectifying bridge having an input and an output, and a motor bridge having an input and output, the rectifying bridge input adapted to be coupled to the alternating-electricity source and the rectifying bridge output being coupled to the motor bridge input, the motor bridge output adapted to be coupled to the electric motor; an inverter control coupled between the voltage determining device and the motor bridge, the inverter control being responsive to a frequency and phase of the determined voltage of the alternating-electricity source to adjust the frequency and phase of the motor bridge output voltage such that the frequency and phase of the output voltage of the motor bridge is made to be essentially constant; and a switch arrangement configured to connect the electric motor directly to the alternating electricity source after a determined loading of the conveyor exceeds a set limit value.