摘要:
A power supply adapted to be coupled in series electrical connection between an AC voltage source and an electrical load for generating a DC voltage, the power supply comprising an energy storage capacitor, the DC voltage produced across the capacitor; a charging circuit adapted to be coupled in series electrical connection between the source and the load and to conduct a load current from the source to the load, the charging circuit coupled to the energy storage capacitor for charging the energy storage capacitor; a controllably conductive device coupled in parallel electrical connection with the charging circuit and having a control input for rendering the controllably conductive device conductive, the controllably conductive device adapted to carry the load current from the source to the load when the controllably conductive device is conductive; and a triggering circuit coupled to the control input of the controllably conductive device for causing the controllably conductive device to become conductive when the energy storage capacitor has charged to a desired maximum value; wherein the charging circuit is adapted to conduct the load current from the source to the load when the controllably conductive device is non-conductive, the charging circuit imposing a low voltage drop relative to the peak value of an AC voltage of the AC voltage source, such that substantially all of the AC voltage is available to the load during the time when the controllably conductive device is non-conductive.
摘要:
A load control device is adapted to be disposed in series with an AC voltage source and an electrical load and is operable to provide substantially all voltage provided by the AC voltage source to the load. The load control device comprises a controllably conductive device, a controller, a zero-crossing detector, and a power supply for generating a substantially DC voltage for powering the controller. The power supply is operable to charge an energy storage device to a predetermined amount of energy each half-cycle. The controller is operable to determine when the power supply has stopped charging from the zero-crossing detector each half-cycle, and to immediately render the controllably conductive device conductive to conduct the full load current. Before the controllably conductive device begins to conduct each half-cycle, only a minimal voltage develops across the power supply to allow the energy storage device to charge.
摘要:
A power supply adapted to be coupled in series electrical connection between an AC voltage source and an electrical load for generating a DC voltage, the power supply comprising an energy storage capacitor, the DC voltage produced across the capacitor; a charging circuit adapted to be coupled in series electrical connection between the source and the load and to conduct a load current from the source to the load, the charging circuit coupled to the energy storage capacitor for charging the energy storage capacitor; a controllably conductive device coupled in parallel electrical connection with the charging circuit and having a control input for rendering the controllably conductive device conductive, the controllably conductive device adapted to carry the load current from the source to the load when the controllably conductive device is conductive; and a triggering circuit coupled to the control input of the controllably conductive device for causing the controllably conductive device to become conductive when the energy storage capacitor has charged to a desired maximum value; wherein the charging circuit is adapted to conduct the load current from the source to the load when the controllably conductive device is non-conductive, the charging circuit imposing a low voltage drop relative to the peak value of an AC voltage of the AC voltage source, such that substantially all of the AC voltage is available to the load during the time when the controllably conductive device is non-conductive.
摘要:
A method for controlling the speed of an AC motor by means of an AC motor speed control having a plurality of capacitors operable to be selectively coupled in parallel electrical connection, the parallel coupled capacitors operable to be coupled in series electrical connection with the AC motor, the method comprising charging the capacitors up to substantially the same predetermined voltage prior to combining the capacitors in parallel electrical connection.
摘要:
An AC motor speed controller includes a plurality of capacitors that may be selectively switched, by means of controllably conductive switches, into series electrical connection with an AC motor and an AC voltage source to control the speed of the motor. To change the speed of the motor, a control circuit renders a first switch conductive, in response to a first detected AC voltage zero crossing, to charge a first capacitor to a predetermined voltage. The control circuit then renders a second switch conductive, in response to a subsequent second detected AC voltage zero crossing, to charge a second capacitor to the predetermined voltage. The control circuit then renders both switches simultaneously conductive at a predetermined time after a subsequent third detected AC voltage zero crossing. The capacitors will thereby be charged to the same voltage prior to being switched into series with the motor, thereby resulting in reduced acoustic noise when changing motor speeds.
摘要:
An AC motor speed controller includes a plurality of capacitors that may be selectively switched, by means of controllably conductive switches, into series electrical connection with an AC motor and an AC voltage source to control the speed of the motor. To change the speed of the motor, a control circuit renders a first switch conductive, in response to a first detected AC voltage zero crossing, to charge a first capacitor to a predetermined voltage. The control circuit then renders a second switch conductive, in response to a subsequent second detected AC voltage zero crossing, to charge a second capacitor to the predetermined voltage. The control circuit then renders both switches simultaneously conductive at a predetermined time after a subsequent third detected AC voltage zero crossing. The capacitors will thereby be charged to the same voltage prior to being switched into series with the motor, thereby resulting in reduced acoustic noise when changing motor speeds.
摘要:
An AC motor speed controller includes a plurality of capacitors that may be selectively switched, by means of controllably conductive switches, into series electrical connection with an AC motor and an AC voltage source to control the speed of the motor. To change the speed of the motor, a control circuit renders a first switch conductive, in response to a first detected AC voltage zero crossing, to charge a first capacitor to a predetermined voltage. The control circuit then renders a second switch conductive, in response to a subsequent second detected AC voltage zero crossing, to charge a second capacitor to the predetermined voltage. The control circuit then renders both switches simultaneously conductive at a predetermined time after a subsequent third detected AC voltage zero crossing. The capacitors will thereby be charged to the same voltage prior to being switched into series with the motor, thereby resulting in reduced acoustic noise when changing motor speeds.
摘要:
A method for controlling the speed of an AC motor by means of an AC motor speed control having a plurality of capacitors operable to be selectively coupled in parallel electrical connection, the parallel coupled capacitors operable to be coupled in series electrical connection with the AC motor, the method comprising charging the capacitors up to substantially the same predetermined voltage prior to combining the capacitors in parallel electrical connection.
摘要:
A system for independent control of electric motors and electric lights includes a plurality of two-wire wallstations coupled in series via power wires between an alternating-current (AC) source and a light/motor control unit. The light/motor control unit is preferably located in the same enclosure as an electric motor and an electric light and has two outputs for independent control of the motor and the light. The light/motor control unit and the wallstations each include a controller and a communication circuit that is coupled to the power wiring via a communication transformer and communicate with each other using a loop current carrier technique. The light/motor control unit and the wallstations utilize pseudo random orthogonal codes and a median filter in the communication process.
摘要:
A system for independent control of electric motors and electric lights includes a plurality of two-wire wallstations coupled in series via power wires between an alternating-current (AC) source and a light/motor control unit. The light/motor control unit is preferably located in the same enclosure as an electric motor and an electric light and has two outputs for independent control of the motor and the light. The light/motor control unit and the wallstations each include a controller and a communication circuit that is coupled to the power wiring via a communication transformer and communicate with each other using a loop current carrier technique. The light/motor control unit and the wallstations utilize pseudo random orthogonal codes and a median filter in the communication process.