AND MOTOR CONTROL CENTERS

TECHNICAL FIELD

[0001] This disclosure generally relates to a remote racking tool for use with circuit breakers and switchgears.

BACKGROUND

[0002] Locations such as industrial plants, refineries, offshore oil platforms, hotels, and hospitals employ multiple circuit breakers, typically located within a circuit breaker cabinet. The installation and removal of circuit breaker involves the engagement or disengagement of contacts of the circuit breaker with a power bus within the circuit breaker cabinet. Conventionally, this installation and removal is performed manually by a technician.

[0003] Manual installation and removal, however, may be undesirable for a variety of reasons. For example, when the contacts of the circuit breaker are engaged or disengaged with the power bus, an arc-flash may occur. This arc-flash is a rapid release of energy and can damage the circuit breaker, the circuit breaker cabinet, or other circuit breakers.

[0004] Thus, technology has been developed that reduces the possibility of an arc- flash. While this technology has been relatively successful, it may still involve the manual insertion of a tool into an apparatus within the circuit breaker, and the manual turning of that tool by a technician.

[0005] While the possibility of arc-flash is reduced by this technology, possibility of arc-flash still remains. Therefore, it is desirable for the manual actuation by a technician to be replaced by automated remote actuation.

[0006] However, numerous examples of reliable manually operated technology that reduces the possibility of an arc-flash are installed in locations, or in production, and it may be undesirable to replace or redesign such technology. Therefore, further design of devices that enable previously manually operated circuit breakers to be remotely actuated in an automated fashion, without a redesign of such manually operated circuit breakers, is desirable.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007] FIG. 1 is a front view of a circuit breaker box with a circuit breaker inserted therein.

[0008] FIG. 2 is a perspective view of the circuit breaker box of FIG. 1. [0009] FIG. 3 is a side view from inside the circuit breaker box of FIG. 1.

[0010] FIG. 4 is a view of the circuit breaker box of FIG. 1 with the circuit breaker removed.

[0011] FIG. 5 is an inside side view of the circuit breaker box of FIG. 1 in which the electrical contacts of the circuit breaker are engaged with the power bus of the circuit breaker box.

[0012] FIG. 6 is an inside side view of the circuit breaker box of FIG. 1 in which the electrical contacts of the circuit breaker are disengaged with the power bus of the circuit breaker box.

[0013] FIG. 7 is a rear view of the circuit breaker of FIG. 1.

[0014] FIG. 8 is a perspective view of the drive unit disclosed herein as attached to the circuit breaker box and circuit breaker of FIG. 1.

[0015] FIG. 9 is a front view of the drive unit disclosed herein as attached to the circuit breaker box and circuit breaker of FIG. 1.

[0016] FIG. 10 is a right side view of the drive unit disclosed herein as attached to the circuit breaker box and circuit breaker of FIG. 1.

[0017] FIG. 11 is a right side view of the drive unit disclosed herein as attached to the circuit breaker box and circuit breaker of FIG. 1.

[0018] FIG. 12 is a rear view of the drive unit disclosed herein.

[0019] FIG. 13 is a right side cutaway view of the drive unit disclosed herein as attached to the circuit breaker box and circuit breaker of FIG. 1.

[0020] FIG. 14 is a left side cutaway view of the drive unit disclosed herein as attached to the circuit breaker box and circuit breaker of FIG. 1.

[0021] FIG. 15 is an enlarged cutaway view of the drive unit disclosed herein while operating in an engagement mode.

[0022] FIG. 16 is an enlarged cutaway view of the drive unit disclosed herein while operating in a device actuation mode.

[0023] FIG. 17 is a front view of a tester for use with the drive unit and/or circuit breaker.

[0024] FIG. 18 is a front view of a control box for use with the drive unit and/or circuit breaker.

[0025] FIG. 19 is a rear view of the attachment apparatus of the drive unit disclosed herein.

DETAILED DESCRIPTION [0026] The present description is made with reference to the accompanying drawings, in which example embodiments are shown. However, many different embodiments may be used, and thus the description should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete. Like numbers refer to like elements throughout.

[0027] With reference to FIGS. 1-7, a circuit breaker box or cabinet 50 which houses circuit breaker 52 and carries phase buses 60 (shown best in FIGS. 5-6) to which the circuit breakers 52 are to be electrically coupled is now described. Electrical coupling between the circuit breaker 52 and phase buses 60 is made via movable contacts 58 that extend outwardly from the circuit breaker 52 to contact the phase buses 60, as shown in FIG. 5.

[0028] The movable contacts 58 are rotatable 90 degrees downward, as shown in FIG. 6, so as to break the contact, and thus electrical coupling, between the circuit breaker 52 and phase buses 60. The movement of the movable contacts 58 between a fully open position or first travel limit and a fully closed position or second travel limit is accomplished mechanically by insertion of a tool into tool receptacle 54 to thereby rotate actuator 56 which moves the movable contacts 58. The tool has a polygonally or hex shaped outer surface or cross section which mates with a correspondingly shaped interior surface of the tool receptacle 54. Other males and female shaped tool interfaces may also be used.

[0029] Once the movable contacts 58 are decoupled from the phase buses 60, the circuit breaker 52 may be removed from the circuit breaker cabinet 50, as shown in FIG. 4.

[0030] So as to avoid the manual use of the tool by a technician to rotate the actuator 56, a drive unit 100, as shown in FIGS. 8-9, may be attached to the circuit breaker 52 and function to rotate the actuator 56 via insertion of its internally carried tool into the tool receptacle 54 and rotation thereof.

[0031] The drive unit 100 includes a housing 102 attached to the circuit breaker 52 via the attachment apparatus 110, which itself includes a plate 120 that is latched or unlatched to the cabinet 52 via crank 106. Handles 104 are coupled to the housing 102 to facilitate installation by a technician, and, as shown in FIGS. 10-11, support apparatus 116 provides additional mechanical support for the attachment of the housing 102 to the circuit breaker 52.

[0032] A tool carrying apparatus 114 carries the internal tool 112, which is shaped and dimensioned so as to fit in and turn the tool receptacle 54. A motor apparatus 132 is mechanically coupled to rotate the tool carrying apparatus 114. The motor apparatus 132 itself is comprised of a stepper motor driver 184, which drives a stepper motor 186. A gearbox 188 couples the stepper motor 186 to the tool carrying apparatus 114. Control circuitry 182 controls the stepper motor driver 184, which in turn drives and controls the stepper motor 186. Thus, the control circuitry 182 can be said to control the stepper motor 186. A power supply 180 powers the control circuitry 182, stepper motor driver 184, and stepper motor 186. The power supply 180 receives electrical power to run from an electrical receptacle 118. A proximity detector 130 monitors axial positioning of the tool carrying apparatus 114 within the housing 102, as shown in FIGS. 15-16. The proximity detector 130 provides output to the control circuitry 182.

[0033] As explained above, insertion of the tool into the tool receptacle 54 and rotation thereof serves to engage or disengage the movable contacts 58 from the phase buses 60. However, the exact position and orientation of the tool receptacle 54 may not be consistent between cycles. Thus, if the tool 112 were to be inserted into the tool receptacle 54 in the exact same orientation during each insertion, during some of those insertions, there might be a mismatch between the orientations of the tool 112 and the tool receptacle 54. Therefore, it is desirable for the drive unit 100 to have functionality permitting detection of a mismatch between the orientation of the tool receptacle 54 and tool 112.

[0034] To that end, the tool 112 is biased toward the tool receptacle 54 upon attachment of the drive unit 100 onto the circuit breaker 52. If the tool receptacle 54 and tool 112 are aligned, the tool 112 will enter the tool receptacle 54, and therefore the tool carrying apparatus 114 will be advanced axially toward the tool receptacle 54. Where there is a misalignment, the tool 112 will be unable to enter the tool receptacle 54, and the tool carrying apparatus 114 is unable to be advanced axially toward the tool receptacle 54.

[0035] The biasing of the tool 112 toward the tool receptacle 54 may be present during installation of the drive unit 100 onto the circuit breaker 52, requiring installation against the bias. In some cases however, a bias release mechanism may be present to release the bias during installation so that the drive unit 100 may be installed onto the circuit breaker 52 without the presence of the bias, and the bias then applied thereafter. The bias may be applied using any suitable form of spring, for example.

[0036] The proximity detector 130 detects whether the tool carrying apparatus 114 has moved a threshold distance along its longitudinal axis toward the tool receptacle 54 by detecting presence of a raised shoulder 134 of the tool carrying apparatus 114. If proximity of the raised shoulder 134 is detected, such as in the scenario shown in FIG. 15, then the tool carrying apparatus 114 has not moved the threshold distance along its longitudinal axis toward the tool receptacle 54, and it can be inferred that the tool receptacle 54 and tool 112 are not aligned. As a corollary, if proximity of the raised shoulder 134 is not detected, such as shown in the scenario of FIG. 16, then the tool carrying apparatus 114 has moved the threshold distance along its longitudinal axis toward the tool receptacle 54, and it can be inferred that the tool receptacle 54 and tool 112 are aligned.

[0037] Where misalignment is detected via the proximity sensor 130, the control circuitry 182 controls the motor apparatus 132 in an engagement mode in which it is slowly rotated, such 1 to 30 degrees, until sufficient movement of the tool carrying apparatus 114 is detected and thus alignment is determined.

[0038] Once alignment is reached, or where alignment is detected, then the control circuitry 182 controls the motor apparatus 132 in a device actuation mode in which it is more quickly rotated until the tool receptacle 54 is completely moved from a first travel limit to a second travel limit, to thereby either engage or disengage the movable contacts 58 from the phase buses 60.

[0039] Detection of the tool receptacle 54 being at the first or second travel limit may be made by monitoring power drawn by the motor apparatus 132. For example, a power draw above a given threshold may indicate that the tool receptacle 54 is at the first or second travel limit.

[0040] In other cases, detection of the tool receptacle 54 being at the first or second travel limit may be made by monitoring the status of the movable contacts 58. For example, where the motor apparatus 132 rotates the tool receptacle 54 from a first travel limit at which the movable contacts 58 are disengaged with the power buses 60 to a second travel limit at which the movable contacts 58 are engaged with the power buses 60, the tool receptacle 54 being at the second travel limit may be determined by detection of electrical contact between the movable contacts 58 and the power buses 60. Where the motor apparatus 132 rotates the tool receptacle 54 from a second travel limit at which the movable contacts 58 are engaged with the power buses 60 to a first travel limit at which the movable contacts 58 are disengaged with the power buses 60, the tool receptacle 54 being at the first travel limit may be determined by initial detection of a break in electrical contact between the movable contacts 58 and the power buses 60, and then a given known delay period passing after the break in the electrical contact. In some cases, combinations of the techniques for determining presence at the travel limits may be used.

[0041] These detections of electrical contact may be accomplished by monitoring a sensor or connector within the circuit breaker 52 or cabinet 50. The output of this sensor may be fed via 4-pin connector 54 on the cabinet 50 to 4-pin connector 108 on the housing 102 of the drive unit 100. Any suitable connectors may be used.

[0042] A tester 200, shown in FIG. 17, may be coupled to the connector 109 on the housing 102 of the drive unit 100 to test the current condition of the circuit breaker 52 without actuating the drive unit 100. In addition, a control box 202, as shown in FIG. 17, may be used to direct the control circuitry 182, so as to prepare the circuit breaker 52 for installation or removal.

[0043] A rear view of the attachment apparatus 110 is shown in FIG. 12. Here, it is shown that the plate 120 slides back and forth to latch onto the cabinet 50 using a rack and pinion gear arrangement.

[0044] Many modifications and other embodiments will come to the mind of one skilled in the art having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is understood that various modifications and embodiments are intended to be included within the scope of the appended claims.