CLIAMS:1. An apparatus for automated mechanical testing of at least one circuit breaker, the apparatus coupled to the circuit breaker with at least one crank handle, and the apparatus CHARACTERIZED IN THAT COMPRISING:
at least one gear mechanism with at least one optical encoder coupled to at least one direct current (DC) motor;
at least one counter coupled to the gear mechanism;
at least one microcontroller coupled to the DC motor and configured to receive a feedback from the circuit breaker;
at least one indicator; and
at least one photosensitive transistor or phototransistor separated by a gap from the indicator; wherein
the optical encoder circuit uses the gear mechanism to rotate the crank handle using the DC motor.

2. The apparatus as claimed in claim 1, wherein the crank handle of hexagonal shape and is clamped in a toolkit clamped on a disk of the DC motor at one end and the other end of the crank handle is fixed to the circuit breaker.

3. The apparatus as claimed in claim 1, wherein the optical encoder is configured to estimate an angle of a shaft coupled to the crank handle.

4. The apparatus as claimed in claim 1, wherein the indicator is an infrared (IR) LED and is configured to emit light towards a photosensitive transistor or phototransistor mounted in one package, separated by the gap.

5. The apparatus as claimed in claim 1, wherein the dc motor with the crank handle racks in and out the circuit breaker ensures a number of times the circuit breaker is racked in or out from the optical encoder.

6. The apparatus as claimed in claim 1, wherein the DC motor is communicably coupled to the microcontroller which controls a speed of a rotating the crank handle.

7. The apparatus as claimed in claim 1, wherein the DC motor with gear mechanism is coupled to the optical encoder and the counter.

8. The apparatus as claimed in claim 1, wherein the counter is configured to count a number of times the circuit breaker is racked in or out.

9. The apparatus as claimed in claim 1, wherein a speed of the crank handle and a torque applied to the crank handle is controlled based on the feedback received from the microcontroller.

10. The apparatus as claimed in claim 1, wherein the counter is configured to count a number of times the circuit breaker is successfully racked in or out and/or unsuccessfully racked in or out.

11. The apparatus as claimed in claim 1, wherein the DC motor rotates based on an input from microcontroller and the optical encoder.

12. The apparatus as claimed in claim 1, wherein the microcontroller is programmable for the number of racked in or out with a torque pre-specified to be applied on the crank handle.

13. The apparatus as claimed in claim any of the preceding claims, wherein the torque causes the crank handle to rotate and rack in or out the circuit breaker and thereby count a number of times the circuit breaker is successfully racked in or out and/or unsuccessfully racked in or out.

14. A testing mechanism for automated mechanical testing of at least one circuit breaker, the testing mechanism comprising:
a crank handle coupled to a shaft, and configured to rotate the shaft;
an optical encoder using a gear mechanism to rotate the crank handle using a direct current (DC) motor, wherein the optical encoder is configured to rotate the shaft in a particular angle;
an infrared (IR) LED configured to emit light towards a photosensitive transistor or a phototransistor separated by a gap, wherein the phototransistor is configured to detect an on-off-on or off-on-off cycle of the circuit breaker.

14. The testing mechanism as claimed in claim 13, comprises the circuit breaker with crank handle is connected to at least one arm of the DC motor, wherein the dc motor with the crank handle racks in and out the circuit breaker so as to ensure of a number of times the circuit breaker is racked in or out from the optical encoder.

15. The testing mechanism as claimed in claim 13 comprises a microcontroller connected to the DC motor and configured to control a speed of the rotating handle.

16. The testing mechanism as claimed in claim 13 comprises at least one counter coupled to the optical encoder connected to the DC motor with gear mechanism, and is configured to a number of times the circuit breaker is racked in or out from the optical encoder.

17. The testing mechanism as claimed in any of the preceding claims, wherein, a speed of the crank handle and a torque applied to the crank handle is controlled based on a feedback received from the microcontroller.
,TagSPECI:TECHNICAL FIELD

[001] The present subject matter described herein, in general, relates to racking devices for drawable circuit breakers into switchgear cells, and more particularly to circuit breakers with crank handle that checks the mechanical functionality of circuit during testing.

BACKGROUND

[002] Circuit breakers used in switchgear systems are often built with a draw-out configuration, which allows breaker insertion or removal in a cradle assembly without disturbing power circuit connections. The draw-out breakers have a connected position in which connector fingers of the breakers are connected to respective bus connectors of bus bars or plug in device, and a test position in which the connector fingers are disconnected from the bus connectors or plug in device. To ensure this functionality it becomes necessary to the test the circuit breakers for its mechanical rack in rack out operation.

[003] The circuit breaker can control and protect an electrical circuit and people operating the utilization equipment. Circuit breakers are very reliable components of an electrical system; however, they are man-made and are subject to becoming defective. A draw out circuit breaker also has two parts, the base, which is bolted and wired to the frame and the actual breaker, which slides into and electrically mates with the base. This allows the unit to be replaced without having to turn off the power feeding the breaker. The load must be turned off in order to test or remove the unit.

[004] As a safety feature these units are interlocked to automatically turn the power off just before removal of the breaker begins. By design, only the circuit breakers load must be turned off to remove the breaker. This method of mounting allows for a single breaker to be disconnected from the power supply. That is to say that it does not require that all of the power be disconnected from all of the breakers installed in the larger enclosure such as a motor control center.

[005] There are various designs used to facilitate the “racking-in” (installation) and “racking out”(withdrawal) of the draw out type circuit breakers. Some utilize some form of jacking screw to initially move and thus electrically disengage the breaker, then a traveling trolley type of hoist (somewhat like a small boat winch) supports the breaker during removal and re-installation. A transient supporting device is necessary as these large (physical size) breakers are too heavy and too bulky to be safely moved into and out of position by one person.

[006] Thus there is need for an efficient mechanism to check functionality of rack in and rack out of draw out circuit breakers.

SUMMARY OF THE INVENTION

[007] The following presents a simplified summary of the invention in order to provide a basic understanding of some aspects of the invention. This summary is not an extensive overview of the present invention. It is not intended to identify the key/critical elements of the invention or to delineate the scope of the invention. Its sole purpose is to present some concept of the invention in a simplified form as a prelude to a more detailed description of the invention presented later.

[008] An object of the present invention is to provide an alternate for automatic testing of rack in and rack out operation through the use of optical encoder circuitry in the mechanical testing of the circuit breakers.

[009] Another object of the present invention is to check functionality of rack in and rack out of draw out circuit breakers.

[0010] Yet another object of the present invention to provide a testing apparatus for fixing a power circuit breaker in a withdrawable-part rack. The apparatus fixes the power circuit breaker securely in the withdrawable-part rack, even in the event of very high forces and which acts automatically, i.e. without any additional effort on the part of the operator, when the power circuit breaker is inserted in the withdrawable-part rack.

[0011] Yet another object of the present invention is to provide a crank handle apparatus for a draw-out circuit breaker. Since only the control end of the locking mechanism is kept out of the panel and the remaining parts are generally arranged within the panel, the mal-operation of the crank handle can be detected.

[0012] Yet another object of the present invention is to provide a force arm for rotating the crank can be lengthened to ensure a reliable, convenient and labor-saving operation for drawing-out or pushing-in the breaker body.

[0013] Yet another object of the present invention is to reduce lead time in testing, and to bring more precise results economically.

[0014] Yet another object of the present invention is to make the circuit breaker more reliable by checking the vulnerability of the operating mechanisms in particular when extraction and handling operations of the circuit breaker are performed.

[0015] Yet another object of the present invention is to enable a testing technician to determine the count of number of fault indication during the rack in rack out operation of the circuit breakers.

[0016] Still another object of the present invention is to make testing more economical and efficient by automatically performing the intrusion and extraction operation of circuit breakers.

[0017] Accordingly, in one implementation, an apparatus for automated mechanical testing of at least one circuit breaker, the apparatus coupled to the circuit breaker with at least one crank handle is disclosed. The apparatus may include at least one gear mechanism with at least one optical encoder coupled to at least one direct current (DC) motor; at least one counter coupled to the gear mechanism; at least one microcontroller coupled to the DC motor and configured to receive a feedback from the circuit breaker; at least one indicator; and at least one photosensitive transistor or phototransistor separated by a gap from the indicator; wherein the optical encoder circuit uses the gear mechanism to rotate the crank handle using the DC motor.

[0018] In one implementation, a testing mechanism for automated mechanical testing of at least one circuit breaker is disclosed. The testing mechanism includes a crank handle coupled to a shaft, and configured to rotate the shaft; an optical encoder using a gear mechanism to rotate the crank handle using a direct current (DC) motor, wherein the optical encoder is configured to rotate the shaft in a particular angle; an infrared (IR) LED configured to emit light towards a photosensitive transistor or a phototransistor separated by a gap, wherein the phototransistor is configured to detect an on-off-on or off-on-off cycle of the circuit breaker.

[0019] The present invention provides the optical encoder along with the dc motor and the circuitry which enables the rack in and rack out of the circuit breaker automatically. The optical encoder along with gear mechanism and dc motor will rotate the crank handle in both the directions and check the operational functionality of the circuit breaker.

[0020] Other aspects, advantages, and salient features of the invention will become apparent to those skilled in the art from the following detailed description, which, taken in conjunction with the annexed drawings, discloses exemplary embodiments of the invention.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

The above and other aspects, features, and advantages of certain exemplary embodiments of the present invention will be more apparent from the following description taken in conjunction with the accompanying drawings in which:

[0021] Figure 1 illustrates a typical installation of MCCBs .

[0022] Figure 2 illustrates an optical encoder circuitry interfaced with counter, in accordance with an embodiment of the present subject matter.

[0023] Figure 3 illustrates a crank handle with hexagonal shape to be terminated at DC motor, in accordance with an embodiment of the present subject matter.

[0024] Figure 4 illustrates an optical encoder interfaced with the gear mechanism to move the motor reverse and forward, in accordance with an embodiment of the present subject matter.

[0025] Figure 5 illustrates a block diagram of the mechanical endurance test set up, in accordance with an embodiment of the present subject matter.

[0026] Figure 6 illustrates the mechanical endurance test setup for circuit breakers with crank handle, in accordance with an embodiment of the present subject matter.

[0027] Persons skilled in the art will appreciate that elements in the figures are illustrated for simplicity and clarity and may have not been drawn to scale. For example, the dimensions of some of the elements in the figure may be exaggerated relative to other elements to help to improve understanding of various exemplary embodiments of the present disclosure. Throughout the drawings, it should be noted that like reference numbers are used to depict the same or similar elements, features, and structures.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

[0028] The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of exemplary embodiments of the invention. It includes various specific details to assist in that understanding but these are to be regarded as merely exemplary.

[0029] Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the embodiments described herein can be made without departing from the scope of the invention. In addition, descriptions of well-known functions and constructions are omitted for clarity and conciseness.

[0030] The terms and words used in the following description and claims are not limited to the bibliographical meanings, but, are merely used by the inventor to enable a clear and consistent understanding of the invention. Accordingly, it should be apparent to those skilled in the art that the following description of exemplary embodiments of the present invention are provided for illustration purpose only and not for the purpose of limiting the invention as defined by the appended claims and their equivalents.

[0031] It is to be understood that the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise.

[0032] By the term “substantially” it is meant that the recited characteristic, parameter, or value need not be achieved exactly, but that deviations or variations, including for example, tolerances, measurement error, measurement accuracy limitations and other factors known to those of skill in the art, may occur in amounts that do not preclude the effect the characteristic was intended to provide.

[0033] Features that are described and/or illustrated with respect to one embodiment may be used in the same way or in a similar way in one or more other embodiments and/or in combination with or instead of the features of the other embodiments.

[0034] It should be emphasized that the term “comprises/comprising” when used in this specification is taken to specify the presence of stated features, integers, steps or components but does not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof.

[0035] In one implementation, the present invention provides an apparatus for fixing a power circuit breaker in a withdrawable-part rack. For this purpose, a control rod interacts with the device for moving the power circuit breaker relative to the withdrawable-part rack. Further, the apparatus may include a release device, which can be moved by way of the movement of the power circuit breaker from a blocked position for the control rod to a released position for the control rod or vice versa.

[0036] In one implementation, racking-in/out of the moving part is carried out by means of the special operating lever supplied with the circuit-breaker in the moving part for withdrawable version or with the conversion kit of the fixed circuit-breaker into moving part of withdrawable circuit-breaker. The special mechanism allows the circuit-breaker to be put into the isolated position (with power and auxiliary circuits disconnected) with the compartment door closed, providing increased operator safety. The lever can only be inserted with the circuit-breaker open. Once racked out or withdrawn, the circuit-breaker can be operated in the open/closed position and, by means of the special connection extensions, blank operating tests of the auxiliary control circuits can be carried out.

[0037] In one implementation, racking-out handle allows racking-out and racking-in even with the door closed of the circuit-breaker in the fixed part. The handle is the same for the whole range of circuit breakers and is supplied as standard with the conversion kit or with the circuit-breakers supplied in the withdrawable version.

[0038] A single line diagram for the circuit breaker is shown in figure 1. While carrying out a maintenance operation, the circuit must be imparted for future use. The maintenance of breakers at low voltage (LV) side can be assured if there is no connection of line and load at the high tension (HT) side. If there is any fault indication or an improper functioning of the device the results will be fatal. This functionality is verified by the mechanical endurance testing of the circuit breaker so that the jaws of the fixed and the moving part are closed properly, thus avoiding malfunctioning of the circuit breaker.

[0039] As shown in figure 3 the racking out handle called as the crank handle will be in form of hexagonal shape which can be easily clamped in the toolkit clamped on the disk of the dc motor and the other end of the handle will be fixed to the breaker assembly. By rotating the handle clockwise and anticlockwise the breaker can be racked in and racked out of the breaker assembly.

[0040] This functionality is verified in the mechanical endurance testing of circuit breaker wherein the rack in rack out operation of the circuit breaker assure the proper contact of jaws in the circuit and no false indication of the contacts are checked and reported.

[0041] Figure 4 shows an optical encoder circuit which uses the gear mechanism to rotate the crank with the help of DC motor. An optical encoder is the most common accessory for a gear motor. An optical encoder may allow tracking both the direction of rotation and number of revolutions of the motor. With the right code, an optical encoder can also give you the angle of the shaft. An infrared (IR) LED emits light towards a photosensitive transistor phototransistor) mounted in one package, separated by a gap. Every time that the phototransistor detects on-off-on or off-on-off cycle, receiver logic notes/counts the event. By knowing the physical characteristics of the interrupting element (such as number of windows in an opaque wheel per revolution), one may compute the rotational speed of the device on which it is mounted. The above explanation can be visualized from figure 2.

[0042] Figure 5 shows a complete block diagram of how the above invention is embodied in the mechanical endurance test. The circuit breaker with crank handle is connected to the arms of the DC motor. The dc motor with the crank handle racks in and out the circuit breaker from the assembly without any manual intervention. This will ensure of the number of times the breaker can be racked in or out from the circuit without damaging any mechanical components of the breaker. This will be ensured without any manual intervention during testing. The DC motor is also connected to the microcontroller which controls the speed of the rotating handle. The DC motor with gear mechanism is connected to the optical encoder and the counter which counts the number of successful mechanical operations. The speed of the handle and the torque applied to the crank can be controlled based on the feedback received from the microcontroller.

[0043] Figure 6 depicts the circuit diagram of mechanical endurance testing of crank type circuit breakers. There are two counters used in the circuitry. Counter 1 gives the number of actual mechanical operations in the circuitry and the counter 2 depicts the number of faulty operations of the circuit breaker. The faulty operations include the number of missed operation or the faulty indication of the true position of the circuit breaker. The motor rotates based on the input from microcontroller and the optical device. The microcontroller can be programmed for the number of operations with a typical torque to be applied on the crank handle. This applied torque will cause the handle to rotate and rack in or out the circuit breaker and count the number of successful mechanical operations of the circuit.

[0044] Accordingly, in one implementation, an apparatus for automated mechanical testing of at least one circuit breaker, the apparatus coupled to the circuit breaker with at least one crank handle is disclosed. The apparatus may include at least one gear mechanism with at least one optical encoder coupled to at least one direct current (DC) motor; at least one counter coupled to the gear mechanism; at least one microcontroller coupled to the DC motor and configured to receive a feedback from the circuit breaker; at least one indicator; and at least one photosensitive transistor or phototransistor separated by a gap from the indicator; wherein the optical encoder circuit uses the gear mechanism to rotate the crank handle using the DC motor.

[0045] In one implementation, the crank handle of hexagonal shape and is clamped in a toolkit clamped on a disk of the DC motor at one end and the other end of the crank handle is fixed to the circuit breaker.

[0046] In one implementation, the optical encoder is configured to estimate an angle of a shaft coupled to the crank handle.

[0047] In one implementation, the indicator is an infrared (IR) LED and is configured to emit light towards a photosensitive transistor or phototransistor mounted in one package, separated by the gap.

[0048] In one implementation, the dc motor with the crank handle racks in and out the circuit breaker ensures a number of times the circuit breaker is racked in or out from the optical encoder.

[0049] In one implementation, the DC motor is communicably coupled to the microcontroller which controls a speed of a rotating the crank handle.

[0050] In one implementation, the DC motor with gear mechanism is coupled to the optical encoder and the counter.

[0051] In one implementation, the counter is configured to count a number of times the circuit breaker is racked in or out.

[0052] In one implementation, a speed of the crank handle and a torque applied to the crank handle is controlled based on the feedback received from the microcontroller.

[0053] In one implementation, the counter is configured to count a number of times the circuit breaker is successfully racked in or out and/or unsuccessfully racked in or out.

[0054] In one implementation, the DC motor rotates based on an input from microcontroller and the optical encoder.

[0055] In one implementation, the microcontroller is programmable for the number of racked in or out with a torque pre-specified to be applied on the crank handle.

[0056] In one implementation, the torque causes the crank handle to rotate and rack in or out the circuit breaker and thereby count a number of times the circuit breaker is successfully racked in or out and/or unsuccessfully racked in or out.

[0057] In one implementation, a testing mechanism for automated mechanical testing of at least one circuit breaker is disclosed. The testing mechanism includes a crank handle coupled to a shaft, and configured to rotate the shaft; an optical encoder using a gear mechanism to rotate the crank handle using a direct current (DC) motor, wherein the optical encoder is configured to rotate the shaft in a particular angle; an infrared (IR) LED configured to emit light towards a photosensitive transistor or a phototransistor separated by a gap, wherein the phototransistor is configured to detect an on-off-on or off-on-off cycle of the circuit breaker.

[0058] In one implementation, the circuit breaker with crank handle is connected to at least one arm of the DC motor, wherein the dc motor with the crank handle racks in and out the circuit breaker so as to ensure of a number of times the circuit breaker is racked in or out from the optical encoder.

[0059] In one implementation, a microcontroller connected to the DC motor and configured to control a speed of the rotating handle.

[0060] In one implementation, at least one counter coupled to the optical encoder connected to the DC motor with gear mechanism, and is configured to a number of times the circuit breaker is racked in or out from the optical encoder.

[0061] In one implementation, a speed of the crank handle and a torque applied to the crank handle is controlled based on a feedback received from the microcontroller.

[0062] Some of the important features of the present invention, considered to be noteworthy are mentioned below:
1. The present invention avoids the use of human intervention which was required in the conventional systems.
2. The present invention provides accurate measurements about the mechanical operations of the circuit.
3. The present invention provides better reliability in the test circuit.
4. The present invention has established and proved to be efficient for low voltage high current drives where rack in rack out of circuit breaker is controlled through crank handle.
5. The present invention requires less number of hardware required.
6. The present invention reduces testing time.
7. The present invention counts the number of faulty operations or false position indication of circuit breakers.

[0063] It may be understood by the person skilled in that art that, the coupling, joining, fitting of the two components mentioned the present invention may be achieved by any of the existing coupling techniques that may include but not limited to nut and bolt arrangement, gluing, pasting, welding, and the like.

[0064] Although an automated testing mechanism for mechanical endurance test of a withdrawable circuit-breaker have been described in language specific to structural features and/or methods, it is to be understood that the embodiments disclosed in the above section are not necessarily limited to the specific features or methods or devices described. Rather, the specific features are disclosed as examples of implementations of the automated testing mechanism for mechanical endurance test of a withdrawable circuit-breaker.