Motor operator for over-head air break electrical power distribution switches

• US 6,215,263 B1
• Filed: 04/01/1999
• Issued: 04/10/2001
• Est. Priority Date: 04/03/1998
• Status: Expired due to Term

• Current Assignee: S&C Electric Company
• Original Assignee: EnergyLine Systems, Inc.
• Inventors: Berkowitz, Donald S., Nelson, William Christian Tracy, Hammons, John, Bik, Witold, Klusmeyer, Terry R., Isaacson, Stephen F., Heckathorn, Jeff
• Primary Examiner(s): Ro, Bentsu
• Application Number:
  US09/285,498
• Time in Patent Office: 740 Days
• Field of Search: 318/256, 318/257, 318/264, 318/265, 318/266, 318/272, 318/283, 318/286, 318/466, 318/468, 318/432, 318/433, 307/112, 307/116, 307/125, 307/126, 307/139, 307/143
• US Class Current: 318/272
• CPC Class Codes: H01H 2003/266 having control circuits for motor operating switches, e.g. controlling the opening or closing speed of the contacts
• CPC Class Codes: H01H 2071/006 Provisions for user interfaces for electrical protection devices
• CPC Class Codes: H01H 33/36 using dynamo-electric motor
• CPC Class Codes: H02H 7/222 for switches

Abstract

A motor operator for an overhead power switch is disclosed including a microcontroller, a unique and powerful array of well-integrated sensors, a motor and drive developing substantial torque and speed and coupled to a switch actuator and responsive to the microcontroller, and a sophisticated program algorithm stored in memory at the actuator site for dynamically controlling, i.e., governing the various control modes as called for by changing conditions. The sensors include an encoder associated with the motor and drive that develops position information signals fed to the dynamic microcontroller to compute real time information including position, speed, and stopping distance used in conjunction with remote operate commands to open, close and monitor status of the switch in the various ways disclosed. Under the supervision of the microcontroller, a motor drive power switching circuit selectively applies a source of power, such as from an on site battery, to an electric motor to drive the switch toward open or closed position at different speeds, output force levels such as at different torques, and in continuous or incremental movements depending on conditions determined by the microcontroller in response to sensor inputs.

Claims

1. An operator for an overhead electrical power switch, in which the operator comprises:

a controlled motor drive adapted to be coupled to an overhead electrical power switch;

motor drive position sensor producing a signal representing motor drive position; and

dynamic controller for controlling said motor drive in response to the signal produced by said motor drive position sensor, said dynamic controller comprising a digital processor having switch opening and closing modes, said switch opening and closing modes computing stopping distance of said motor drive as a function of motor drive speed determined from the signal representing motor drive position and turning off said motor drive before a predetermined end point of travel of said motor drive in accordance with said computed stopping distance.

2. The operator of claim 1, wherein said processor controls power to said motor drive as a function of speed of said motor drive.

3. The operator of claim 1, wherein said processor controls power to said motor drive as a function of speed and position of said motor drive.

4. The operator of claim 1, wherein said processor controls power to said motor drive as a function of its speed, position, stopping distance and a predetermined end point of travel.

5. The operator of claim 1, wherein said processor controls power to said motor drive by on/off power conditioning.

6. The operator of claim 1, wherein said motor drive has braking and said processor controls the braking as a function of speed, position and a predetermined end point of travel of said motor drive.

7. The operator of claim 6, wherein said braking of said motor drive comprises dynamic braking.

8. The operator of claim 1, wherein said processor dynamically controls power to said motor drive in response to a stored end point of travel of said motor drive.

9. The operator of claim 1, wherein said processor controls power to said motor drive in response to a sensed output force level of said motor drive.

10. The operator of claim 1, further comprising means for sensing motor drive output force level and for producing a signal of output force level and wherein said processor controls power to said motor drive in response to said signal of output force level.

11. The operator of claim 1, further comprising means for sensing an output torque of said motor drive, and wherein said processor controls power to said motor drive in response to said means for sensing output torque of said motor drive.

12. The operator of claim 1, wherein said processor has a jog mode responsive to a manually operated jog control that applies power to said motor drive to cause a jogged movement of said motor drive.

13. The operator of claim 1, wherein said motor drive includes an electrical motor and further comprising a sensor for sensing electrical current and voltage applied to said electrical motor, said dynamic controller responsive to said sensor of electrical current and voltage.

14. The operator of claim 1, wherein said motor drive includes an electrical motor and further comprising a sensor for sensing electrical current and voltage applied to said electrical motor as an indication of output torque, and wherein said dynamic controller includes speed processing for determining speed of the motor drive from said signal representing position, and said dynamic controller being responsive to said sensor for sensing electrical current and voltage and a determined speed to dynamically control said motor drive as a function of motor drive torque.

15. The operator of claim 1, wherein said dynamic controller has means for sensing switch conditions indicating a blockage, said motor drive being direction reversible and said dynamic controller reversing direction of said motor drive in response to said means for sensing of switch conditions indicating blockage.

16. The operator of claim 15, further comprising a motor drive output force level sensing means producing a force level representing signal, and wherein said means for sensing switch conditions indicating blockage is responsive to said force level representing signal.

17. The operator of claim 1, wherein said signal representing motor drive position is applied to said digital processor in a digital form.

18. The operator of claim 1, wherein said dynamic controller has means for detecting an operator failure condition.

19. The operator of claim 18, further comprising a resettable flag indicator responsive to said means for detecting an operator failure condition.

20. The operator of claim 1, wherein said processor detects a condition of said motor drive being uncoupled from a switch.

21. The operator of claim 1, wherein processor is a temperature compensation processor in which said mode of computing stopping distance varies as a function of temperature, and further comprising a temperature sensor producing a signal representing sensed temperature that is communicated to said processor.

22. The operator of claim 1, wherein said processor is a temperature compensation processor that controls power to said motor drive as a function of temperature.

23. The operator of claim 1, wherein said switch opening mode includes first applying power to the motor drive to drive the switch closed and then applying power in a reverse direction to drive the switch open.

24. The operator of claim 1, wherein said dynamic controller is adapted for receiving a switch control command signal for causing an open or closed state of the switch, and has a memory for storing switch travel limits for open and closed states respectively, said dynamic controller further having means for applying power to said motor drive to force the switch to its open or closed state in response to a switch control command signal and in response to stored switch travel limits.

25. A motor operator for an electrical power switch coupled to the operator by a switch actuator, in which the motor operator comprises:

a motor drive adapted to be coupled to the switch actuator, said motor drive having variable output drive levels;

motor drive position sensor producing an electrical signal representing motor drive position;

controlled motor drive power conditioning circuit for applying power to said motor drive; and

a digital controller having a first input adapted for receiving a switch close or open command signal for causing an open or closed state of the switch, a second input coupled to said position sensor for receiving the electrical signal representing motor drive position, a memory for storing digital travel limits representing positions for a switch in open and closed states respectively, said digital controller having an output coupled to said motor drive power conditioning circuit for applying power to said motor drive, said digital controller having a plurality of control modes responsive to command signals and said second input, the plurality of control modes including respective opening and closing modes to cause the actuator to move the switch to its open or closed state respectively in response to an open or close command signal respectively and stored digital travel limits in said memory, the plurality of control modes further including an override control mode responsive to indications of the switch being mechanically blocked or stuck to cause said motor drive power conditioning circuit to vary application of power to said motor drive, the closing mode further including causing said controlled motor drive power conditioning circuit to produce said variable output drive levels during closing.

26. The operator of claim 25, further comprising:

motor drive output force level sensing producing an electrical signal representing a level of force output to the switch actuator; and

said digital controller being responsive to said signal representing level of force output.

27. The motor operator of claim 26 said wherein the override control mode is responsive to a sensing of output force level of said motor drive and said position sensor to alter the application of power to said motor drive.

28. The motor operator of claim 26, wherein said override control mode is responsive to a motor drive output force level for causing said power conditioning circuit to reverse direction of said motor drive.

29. The motor operator of claim 25, wherein said motor drive has stopping characteristics that predict the position of a switch after turning off said motor drive by said drive power conditioning circuit, and said digital controller has a switch stopping distance computation mode that determines the position for turning off the motor drive as a function of the stored travel limits and a present position signal from said position sensor.

30. The motor operator of claim 25, wherein said motor drive includes an electrical motor.

31. The motor operator of claim 25, wherein said motor drive includes a direct current electrical motor.

32. The motor operator of claim 25, wherein said motor drive has a rotating drive shaft and said position sensor has a shaft encoder producing an electrical signal representing movement of said shaft.

33. The motor operator of claim 25, wherein said motor drive has a rotating drive shaft and an output gear box coupled thereto and adapted to be coupled to the switch actuator, and said position sensor includes a shaft encoder coupled to said rotating drive shaft to produce the electrical signal representing position.

34. The motor operator of claim 33, wherein said shaft encoder has an electrical signal output that represents degrees of shaft rotation and corresponding movement of said gear box, and said digital controller including a counting means coupled to said encoder for receiving said electrical signal output therefrom and storing a count representing position.

35. The motor operator of claim 25, wherein said motor drive is reversible for driving the switch actuator and switch toward either open or closed positions, and said position sensor has a device for detecting direction of movement of said motor drive and said electrical signal representing position includes direction and degree of movement.

36. The motor operator of claim 25, wherein said motor drive is an electrical motor and said controlled motor drive power conditioning circuit has variable motor current to provide said variable output drive levels.

37. The motor operator of claim 25, wherein said controlled motor drive power conditioning circuit includes an output power sensing circuit that produces an electrical signal representing the level of power being used by said motor drive to move the switch actuator, and said digital controller has a mode for determining an out of range switch failure condition when said electrical signal representing the level of power is outside predetermined normal operating values.

38. The motor operator of claim 37, wherein said mode for determining an out of range failure condition includes determination of an excessive level of power being used by the drive motor indicating blockage or stuck switch, and changing the application of power to said drive motor in response thereto.

39. The motor operator of claim 37, wherein said output power sensing circuit includes an impedance in circuit with a winding of said electrical motor, and a means for sensing a change in voltage or current at said impedance.

40. A digital controller for a motor operated electrical power switch having at least high and low drive levels, the digital controller comprising:

a first input adapted for receiving a command signal for commanding an open or closed state of a switch, a second input adapted for receiving an electrical signal representing motor position, a third input adapted for receiving an electrical signal representing a motor output force level, said digital controller having a processor mode in which an output causing application of power to a motor operated electrical power switch to drive it to its open or closed state in response to a command signal and varying application of power thereto in response to predetermined conditions of said command signal and signals representing motor position and motor output force level, said digital controller having a switch operating processor that comprises a memory for storing motor positions corresponding to switch open and closed states, said digital controller being responsive to said command signal for commanding an opened or closed condition to apply power to the motor operated electrical power switch to cause it to reach an at rest condition in which said motor position signal is substantially at said stored motor positions, corresponding to said switch open or closed conditions, respectively, said digital controller comprising a switch operating processor that varies between said high and low drive levels in response to said motor position.

41. The digital controller of claim 40 wherein said switch operating processor has a switch opening mode responsive to an open command signal, the predetermined conditions including an open command signal, a predetermined motor output force level being exceeded, and said motor position signal is within a predetermined range.

42. A digital controller for a motor operated electrical power switch, comprising:

a first input adapted for receiving a switch command signal for commanding an open or closed state of a switch, a second input adapted for receiving an electrical signal representing motor position, a processor having switch opening and closing modes for turning on power to the motor operated electrical power switch to drive it toward its open or closed states, respectively, memory for storing stopping point positions for the motor and turning off power in response to reaching said stored motor stopping point positions, said processor mode for closing comprising a dynamic stopping computation for turning off the motor at a dynamically computed begin stopping position that is before the stopping end point position at which the switch comes to rest in its closed state.

43. The digital controller of claim 42, wherein said stopping begin position is a distance Dstop before the end point position and is computed as a function of speed of the motor substantially at the time of reaching the stopping begin position.

44. The digital controller of claim 42, wherein said stopping begin position is a distance Dstop in terms of before the end point of travel of the motor position, and is computed as a function of speed of the motor substantially at the time of reaching the begin stopping position and includes factors of Ddelay=distance traveled at determined speed during a signal processing time interval, Dbrake=distance traveled as a function of determined speed under braking condition, Dforce=a counter force factor decreasing the amount of stopping distance due to the motor working against the switch closing resistance.

45. The digital controller of claim 42, wherein said processor further comprises a mode for setting the stopping end position corresponding to the switch closed state, wherein said memory stores said stopping end position when a switch is driven closed and tensioned at a desired torque.

46. A motor operator for an electrical power switch coupled to the operator by a switch actuator, in which the motor operator comprises:

an electric motor drive adapted to be coupled to a switch actuator;

motor drive position sensor producing an electrical signal representing position of said electric motor drive;

controlled motor drive power conditioning circuit for applying power to said motor drive; and

dynamic digital controller having a first input adapted for receiving a command signal for an open or closed state of the switch, a second input coupled to said position sensor for receiving the electrical signal representing motor drive position, a travel limit memory for storing digital signals representing motor drive positions for a switch in open and closed states respectively, said digital controller having an output coupled to said motor drive power conditioning circuit for applying power to said motor drive to cause the actuator to force the switch to its open or closed state in response to a command signal for an open or closed state of the switch and said stored digital signal representing motor drive positions for said switch open and closed states, and including a closing processor mode for dynamically computing a stopping begin position at which said power conditioning circuit turns off said motor drive so that it spins down to a stopping end position corresponding to a stored travel limit for a switch closed state.

47. The motor operator of claim 46, wherein said controlled motor drive power conditioning circuit includes dynamic braking of said motor drive.

48. The motor operator of claim 46, adapted to be powered by a storage battery and wherein said dynamic digital controller comprises a battery test mode that tests for available battery energy in response to said command signal for switch open or close states prior to causing said motor drive power conditioning circuit to apply power to said motor drive.

49. A method of operating an overhead electrical power switch, comprising:

coupling a motor drive to an overhead electrical power switch through an actuator, said motor drive including an electrical motor;

sensing electrical current and voltage applied to said electrical motor;

sensing motor drive position and producing a signal representing such motor drive position; and

dynamically controlling the motor drive by controlling power thereto in response to the signal produced by said motor drive position sensor, said step of dynamically controlling having a substep of automatically detecting a blockage or stuck switch condition during the opening or closing of the switch, said motor drive being direction reversible and said step of dynamically controlling causing the reversing of direction of said motor drive in response to said step of automatically detecting, said substep of automatically detecting a blockage or stuck switch condition comprising sensing a motor drive output force level and producing a force level representing signal and processing said force level representing signal to determine if it exceeds a predetermined force level.

50. The method of claim 49, wherein the step of dynamically controlling comprises processing in a digital processor to control turning off the power to said motor drive as a function of speed of said motor drive.

51. The method of claim 49, wherein the step of dynamically controlling comprises processing in a digital processor so as to control turning off power to said motor drive as a function of speed and position of said motor drive.

52. The method of claim 49, wherein the step of dynamically controlling comprises processing in a digital processor so as to turn off power to said motor drive as a function of speed, position and a predetermined end point of travel.

53. The method claim 49, wherein the step of dynamically controlling comprises digital processing of when to turn on and turn off power to said motor drive in response to stored end points of motor drive position corresponding to switch travel limits.

54. The method of claim 49, wherein the step of dynamically controlling said motor drive includes dynamic braking of said motor drive as a function of speed, position and end points of said motor drive position.

55. The method of claim 54, wherein said dynamic braking of said motor drive comprises braking by shorting power thereto.

56. The method of claim 49, wherein said step of dynamically controlling comprises digital processing of controlled conditioning of power to said motor drive in response to predetermined end points of travel of said motor drive corresponding to desired travel limits of a switch.

57. The method of claim 49, wherein said step of dynamically controlling comprises digital processing of conditioning of power to said motor drive in response to an output force level of said motor drive.

58. The method of claim 49, further comprising the step of sensing a motor drive output force level by monitoring voltage and current to said motor drive and wherein said step of dynamically controlling comprises digital processing for controlling power to said motor drive in response to said output force level.

59. The method of claim 49, further comprising the step of sensing motor drive output force level and producing a signal representing a level of output force of said motor drive, and wherein said step of dynamically controlling comprises digital processing for controlling power to said motor drive in response to a predetermined level of output force of said motor drive.

60. The method of claim 49, further comprising the step of producing jog movement of said motor drive in a digitally controlled jog mode process responsive to a manually operated jog control.

61. The method of claim 49, wherein said motor drive includes an electrical motor and further comprising the steps of sensing electrical current and voltage applied to said electrical motor, and wherein said step of dynamically controlling responds to said sensing electrical current and voltage.

62. The method of claim 49, wherein said motor drive includes an electrical motor and further comprising the steps of sensing electrical current and voltage applied to said electrical motor, and wherein said step of dynamically controlling said motor drive includes digital speed processing to determine speed of the motor drive from said signal representing position, and responding to said sensing of electrical current and voltage and determined speed to dynamically control said motor drive as a function of motor drive torque.

63. The method of claim 49, wherein said step of dynamically controlling the motor drive includes the substep of responding to a switch opening or closing command, and further comprising a delay timer mode that is enabled by a manual control for automatically delaying the response to said switch opening or closing command for a predetermined delay.

64. An operator for an overhead electrical power switch, in which the operator comprises:

a controlled motor drive adapted to be coupled to an overhead electrical power switch;

motor drive position sensor producing a signal representing motor drive position;

a dynamic controller for controlling said motor drive in response to the signal produced by said motor drive position sensor; and

a processor having a jog mode responsive to a manually operated jog control that applies power to said motor drive to cause a jogged movement of said motor drive.

65. The operator of claim 64, said processor having a memory for storing an end point of travel of said motor drive, said processor memory coacting with said jog mode for storing the end point of travel following said jogged movement.

66. The operator of claim 65, further comprising a means for sensing a motor drive output force level, said processor memory and processor jog mode coacting with said means for sensing motor drive output force level for storing in said memory an end point of travel that corresponds to a predetermined level of output force of said motor drive.

67. An operator for an overhead electrical power switch, in which the operator comprises:

a controlled motor drive adapted to be coupled to an overhead electrical power switch;

a motor drive position sensor producing a signal representing motor drive position;

a dynamic controller for controlling said motor drive in response to the signal produced by said motor drive position sensor, said dynamic controller comprising a digital processor having switch opening and closing modes, said switch opening and closing modes computing stopping distance of said motor drive as a function of motor drive speed determined from the signal representing motor drive position and turning off said motor drive before a predetermined end point of travel of said motor drive in accordance with said computed stopping distance, said dynamic controller having a temperature compensation processor in which said mode of computing stopping distance varies as a function of temperature;

a temperature sensor producing a signal representing sensed temperature that is communicated to said dynamic controller.

68. An operator for an overhead electrical power switch, in which the operator comprises:

a controlled motor drive adapted to be coupled to an overhead electrical power switch;

motor drive position sensor producing a signal representing motor drive position; and

a dynamic controller for controlling said motor drive in response to the signal produced by said motor drive position sensor, said dynamic controller including a temperature compensation processor that controls power to said motor drive as a function of temperature.

69. A method of operating an overhead electrical power switch, comprising:

coupling a motor drive to an overhead electrical power switch through an actuator;

sensing motor drive position and producing a signal representing such motor drive position;

dynamically controlling the motor drive by controlling power thereto in response to the signal produced by said motor drive position sensor; and

producing jog movement of said motor drive in a digitally controlled jog mode process responsive to a manually operated jog control.

70. The method of claim 69, further comprising step of storing in a digital memory end points of travel position of said motor drive, said step of storing in memory coacting with said step of producing jog movement for storing end points of travel position following said jog movement.

71. The method of claim 69, further comprising the step of sensing a motor drive output force level, said step of storing in memory and said step of jog movement caused by said jog mode coacting with said step of sensing said motor drive output force level for storing in said memory an end point of travel position that corresponds to a predetermined level of output force of said motor drive to tension the power switch.

72. A method of operating an overhead electrical power switch, comprising:

coupling a motor drive to an overhead electrical power switch through an actuator, said motor drive including an electrical motor;

sensing electrical current and voltage applied to said electrical motor;

sensing motor drive position and producing a signal representing such motor drive position; and

dynamically controlling the motor drive by controlling power thereto in response to a switch command signal for commanding an open or closed state of the switch, the signal produced by a motor drive position sensor and stored end points of travel of the motor drive corresponding to open and closed positions of the switch, said step of dynamically controlling having switch opening and closing substeps for controlling the motor drive between the stored end points, said closing substep having a completion substep to ensure that the switch is in a fully closed position.

73. The method of claim 72 wherein the completion substep controls the motor drive toward the stored end point corresponding to the closed position and senses the motor drive position sensor to determine any movement of the motor drive.

74. The method of claim 73 wherein the completion substep is repeated until there is no movement of the motor drive.

75. The method of claim 74 wherein the completion substep compares the final closed position to the stored end point, a recalibration indication being declared if the final closed position is not within a predetermined range of the stored end point.

76. The method of claim 72 wherein the completion substep responds to the motor drive position signal being at the stored end point corresponding to the closed position for controlling motor drive until there is no change in the motor drive position signal.

77. A digital controller for a motor operated electrical power switch having at least high and low drive levels, comprising:

a first input adapted for receiving a command signal for commanding an open or closed state of a switch, a second input adapted for receiving an electrical signal representing motor position, said digital controller having a processor mode in which an output causing application of power to a motor operated electrical power switch to drive it to its open or closed state in response to a command signal, said controller having a switch operating processor that comprises a memory for storing motor positions corresponding to switch open and closed conditions, said digital controller being responsive to said command signal for commanding an opened or closed condition to apply power to the motor operated electrical power switch to cause it to reach an at rest condition in which said motor position signal is substantially at said stored motor positions, respectively, corresponding to said switch open or closed conditions, said digital controller further being responsive to the motor position signal being at the substantially stored motor position corresponding to the switch closed position for driving the motor operated electrical switch until there is no change in the motor position.

78. A digital controller for a motor operated electrical power switch, comprising:

a first input adapted for receiving a switch command signal for commanding an open or closed state of a switch, a second input adapted for receiving an electrical signal representing motor drive position, a processor having switch opening and closing modes for turning on power to the motor operated electrical power switch to drive it toward its open or closed states, respectively, memory for storing stopping point positions for the motor drive and turning off power in response to reaching said stored motor stopping point positions, said digital controller comprising a memory for storing a stopping end position value representing the end of travel of the motor drive where the switch is at rest in its closed state, said processor further comprising a setting mode for setting the stopping end position corresponding to the switch closed state, wherein said memory stores said stopping end position when a switch is driven closed and tensioned at a desired torque.