Automatic sensing of bypassing of soft starter or controller
AssigneeSiemens Energy & Automation, Inc.
InventorLynn Stewart Johnson
Life of this patent
Estimating the term…
Abstract
A motor controller controls a motor operated by an AC line voltage. The controller includes an SCR connectable between an AC line and a motor terminal for controlling application of AC line voltage to the motor. Contacts are connected in parallel with the SCRs for selectively bypassing the SCRs. A sensing circuit senses if the contacts are bypassing the SCRs. A control is connected to the sensing circuit and the SCRs for varying relative duration of on time and off time of the SCRs during each cycle of line voltage to control motor voltage at a reference level. The control adds a time delay to a running operation prior to turning the SCRs off to stop the motor if the contacts are bypassing the SCRs.
Claims24
A motor controller for a motor operated by an AC line voltage comprising:
- solid state switch means connectable between an AC line and a motor terminal for controlling application of AC line voltage to the motor,
- sensing means for automatically sensing if a voltage pulse occurs across the solid state switch means at a zero crossing of a current of the solid state switch means, the voltage pulse characterized by a deviation from, and return to, a reference voltage.
A motor controller for a motor operated by an AC line voltage comprising:
- SCRs connectable between an AC line and a motor terminal for controlling application of AC line voltage to the motor;
- a sensing circuit for sensing if a voltage pulse occurs across said SCRs between conduction of said SCRs, the voltage pulse characterized by a deviation from, and return to, a reference voltage.
A method of automatically sensing bypassing of a motor controller for a motor operated by an AC line voltage comprising:
- providing SCRs connectable between an AC line and a motor terminal for controlling application of AC line voltage to the motor;
- automatically sensing if a voltage pulse occurs across the SCRs between conduction of the SCRs, the voltage pulse characterized by a deviation from, and return to, a reference voltage.
A motor controller for a motor operated by an AC line voltage comprising:
- a solid state switch connectable between an AC fine and a motor terminal, and adapted to, in an operative configuration, control application of AC line voltage to the motor;
- a circuit adapted to, in an operative configuration, transmit a signal if a voltage pulse occurs across said solid state switch, the voltage pulse characterized by a deviation from, and return to, a reference voltage.
A motor controller for a motor operated by an AC line voltage comprising:
- a solid slate switch connectable between an AC line and a motor terminal, and adapted to, in an operative configuration, control application of AC line voltage to the motor;
- a circuit adapted to, in an operative configuration, transmit a signal if a voltage pulse occurs across said solid state switch during time between a conduction of said solid state switch, the voltage pulse characterized by a deviation from, and return to, a reference voltage.
A method of operating a motor controller for a motor operated by an AC line voltage comprising:
- providing a solid state switch connectable between an AC line and a motor terminal, and adapted to, in an operative configuration, control application of AC line voltage to the motor,
- automatically transmitting a signal if a voltage pulse occurs across the solid state switch, the voltage pulse characterized by a deviation from, and return to, a reference voltage.
Dependencies are inferred from the claim text.