| 摘要 |
A system in which the operation of an electric motor is controlled by electronically controlled switches. The system includes the motor having a run winding and a start winding, a heating component, and a motor control subsystem. A control unit closes a first switch to energize the run winding, closes a second switch to energize the start winding, determines based on an amplitude and a lag time of a current flowing through the motor whether the motor has started and is running normally, and if so, opens the second switch to de-energize the start winding and closes a third switch to activate the heating component. The control unit determines whether the motor has started and is running normally by comparing the real time amplitude and lag time of the current to a plurality of stored amplitudes and lag times associated with different operating conditions. |
| 主权项 |
1. A machine comprising:
an electric motor system including—
an electric motor having a run winding and a start winding, anda motor control subsystem electrically connected to the electric motor and operable to control operation of the electric motor, the motor control subsystem including—
a control unit,a user interface in electrical communication with the control unit and operable to receive a user input from a user and communicate the user input to the control unit,a first electronically controlled switch electrically connected in series between the control unit and the run winding of the electric motor and operable to control a flow of electric current to the run winding in response to a first control signal from the control unit,a second electronically controlled switch electrically connected in series between the control unit and the start winding of the electric motor and operable to control the flow of electric current to the start winding in response to a second control signal from the control unit,a voltage sensor in electrical communication with the control unit and operable to sense a voltage being applied to the electric motor and to provide a first input signal to the control unit regarding the sensed voltage, anda current sensor in electrical communication with the control unit and electrically connected in series with the electric motor and operable to sense the electric current flowing through the electric motor and to provide a second input signal to the control unit regarding the sensed current,wherein the control unit sends a first control signal to close the first electronically controlled switch and thereby energize the run winding of the electric motor, sends a second control signal to close the second electronically controlled switch and thereby energize the start winding of the electric motor, determines based on the first and second input signals whether the electric motor has started, and if the electric motor has started, sends a third control signal to open the second electronically controlled switch and thereby de-energize the start winding of the electric motor. |
