Claims:1. An automated system for fastening a contact in a switchgear, the automated system comprises:
a contact fastening means;
a voltage drop (mV) measurement means for measuring a value of voltage drop (mV) for said contact; and
a logic circuit;
wherein the logic circuit commands said contact fastening means to tighten or loosen the contact based on the measured value of voltage drop (mV).
2. The automated system of claim 1, wherein the system monitors the value of voltage drop (mV) in real-time during tightening or loosening said contact by said contact fastening means.
3. The automated system of claim 1, wherein the logic circuit commands said contact fastening means to tighten the contact in case the measured value of voltage drop (mV) is higher than a pre-determined upper threshold.
4. The automated system of claim 1, wherein the logic circuit commands said contact fastening means to loosen the contact in case the measured value of voltage drop (mV) is lower than a pre-determined lower threshold.
5. The automated system of claim 1, wherein the logic circuit commands said contact fastening means to tighten the contact in case the measured value of voltage drop (mV) is higher than 0.55 mV and wherein the logic circuit commands said contact fastening means to loosen the contact in case the measured value of voltage drop (mV) is lower than 0.5 mV.
6. The automated system of claim 1, wherein the automated system further comprises a contact sluggishness checking means.
7. The automated system of claim 8, wherein the contact sluggishness checking means comprises a pneumatic cylinder and a sensor, wherein the pneumatic cylinder presses the contact and wherein the sensor detects a return movement of said contact to effect measurement of contact sluggishness.
8. A method for fastening a contact in a switchgear assembly, the method comprising the steps of:
measuring a value of voltage drop (mV) for said contact;
tightening or loosening of said contact based on the measured value of voltage drop (mV) for said contact.
9. The method of claim 7, wherein the value of voltage drop (mV) is monitored in real-time during said tightening or loosening of said contact.
10. The method of claim 7, wherein said contact is tightened in case the measured value of voltage drop (mV) is found to be higher than the pre-determined upper threshold and wherein said contact is loosened in case the measured value of voltage drop (mV) for said contact is found to be lower than the pre-determined lower threshold.
11. The method of claim 7, wherein said contact is tightened in case the measured value of voltage drop (mV) is found to be higher than 0.55 mV and wherein said contact is loosened in case the measured value of voltage drop (mV) for said contact is found to be lower than 0.5 mV.
12. The method of claim 7, wherein the method further comprises the steps of:
measuring a value for sluggishness of said contact;
comparing the measured value for sluggishness of said contact with a pre-determined sluggishness threshold;
measuring a value of voltage drop (mV) for said contact; and
verifying the measured value of voltage drop (mV) for said contact to be between 0.50 mV and 0.55 mV.
, Description:TECHNICAL FIELD
[0001] The disclosure generally relates to low voltage electrical power systems. In particular, it pertains to an automated system for low voltage electrical switchgears to check and remove contact sluggishness by fastening the lower contact and terminal joint of a switchgear based on closed loop feedback system based on value of voltage drop (mV) monitored in real time, thereby increasing the reliability and productivity of the system.
BACKGROUND
[0002] Background description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.
[0003] The electrical equipment or electrical switchgear used in electric power distribution installations for power grid switching and/or protection from over-current or overload matter are made-up of different compartments. On one hand, there are compartments such as the corresponding compartment for busbars, fuses, grid line connection, elements performing the corresponding switching and protection functions, i.e. acting like a switch, disconnect switch, grounding disconnect switch and the like. On the other hand, there are compartments corresponding to the control, measuring and protection elements configured for measuring and controlling the state of at least some of said electric power distribution elements such that these later elements allow controlling the flow of electric power and thus serving to both control power distribution and protect the different elements and equipment forming the distribution system.
[0004] In a low-voltage switchgear system, busbars supplying the current run horizontally, while perpendicular or vertically running distribution bars are associated with the busbars. The individual control, switching and regulating devices are located in withdrawable trays, contact elements, which surround the distribution bars in the form of a mouth, being provided on the withdrawable trays. In the event of improper maintenance or for other reasons, there is a risk, due to high current densities, of even small deviations in the contact forces leading to a high increase in temperature at these contact points. Thus, the testing of the contact resistance of dry circuit contacts, and particularly low power contacts is important. The primary requirement for dry circuit testing of contacts is that the voltage and current applied to the test contacts must never be allowed to exceed certain maximum limits as that may lead to functional deterioration or premature failure of these devices.
[0005] The potential difference (mV) particularly is a very important factor in the performance of a switchgear product because mV value outside the prescribed band can lead to sluggish moving contact and temperature rise while in operation thereby drastically reducing the life of a switchgear product. Temperature rise in any switchgear product happens when there is resistance in current carrying path.
[0006] One such test to assess the electrical integrity of connections and contacts in a circuit breaker/switchgear is a milli-volt drop test that measures the potential difference (mV) between the moving contact and fixed contact of a switchgear. This test can detect abnormal conditions in a switchgear such as eroded contacts, contaminated contacts, or loose internal connections.
[0007] The milli-volt required across the lower contact and the terminal of low voltage electrical switchgear varies around 0.5 mV to 0.55 mV. In prior-art methods, switchgears were manually tightened or loosened with normal or electrical screw drivers first and then the electrical integrity of connections and contacts in the switchgears were checked by measuring the mV values across the lower contact and the terminal of low voltage electrical switchgear and the whole process was repeated again and again till the mV value reached between 0.5 mV to 0.55 mV.
[0008] In the aforementioned method, open loop system was employed wherein there were separate controls for the fastening of the lower contact with the terminal and for checking of the mV value. One of the drawbacks associated with the above method was the possibility of the assembly being loose or tight according to the variation of the mating parts and the extent of force applied or manual control. Sometimes, the fastened part behaved differently while measuring mV. This leads to frequent tightening and loosening of the assembly to achieve the desired mV value. So, the assembly needed to be re-checked by activating the mV measurement assembly, every time the motor completed a rotation. Hence, these methods were very subjective and dependent on the person carrying out the assembly.
[0009] US patent number 4,491,797 discloses the testing of dry circuit contacts when a constant current source is applied to the contacts. The open circuit voltage of the source is set to a predetermined maximum value and then the short circuit current at the contacts is measured. If the current value is below a predetermined maximum value, the voltage of the source is increased to bring the short-circuit current to the predetermined value. The voltage drop across the contacts is then measured and the contact resistance calculated. This arrangement makes adjustments to take into account variations in the test circuit, such as different lead lengths and other variables, without subjecting the contacts at any time to an open circuit voltage or short circuit current above maximum values. However, it fails to disclose an automated system that measures the mV values and fasten or loosen the switchgears accordingly.
[0010] An Indian patent application 2381/KOLNP/2007 discloses an automation system that includes a device detecting measured values of current and voltage and is connected to an automated process. It further includes a field device which is connected to the measured-value detection device, and a master computer. The measured-value detection device, field device, and the master computer are connected to a common data transmission network which is equipped for transmitting digital measured data from the measured-value detection device to the field device according to a first communication protocol and transmitting digital control data between the field device and the master computer according to a second communication protocol. The disclosure provides for the use of an open loop system to detect any measured value of a current or voltage and to transmit the measured value to a field system. However, the disclosure fails to provide an integrated system that can detect the measured values of current or voltage and fasten or loosen the switchgears according to the feedback of the measured-value detection device.
[0011] After careful scrutinization of prior arts, a person skilled in the art would immediately realize that none of the prior art specifically discloses a closed loop system between a screw driver (or contact tightening means), mV measurement system and the contact sluggishness checking system of a switchgear that can overcome one or more drawbacks associated with conventional methods and systems for fastening lower contacts with the terminal in switchgears.

OBJECTS OF THE INVENTION
[0012] An object of the present disclosure is to overcome one or more disadvantages associated with conventional methods and systems for fastening lower contacts with the terminal in switchgears.
[0013] Another object of the present disclosure is to provide a system and methods to automate fastening of lower contacts with the terminal in switchgears.
[0014] Another object of the present disclosure is to provide a system and methods to reduce the time required for assembling the switchgear.
[0015] Another object of the present disclosure is to provide a system and methods that can enable a user to achieve better control over the milli-volt value.
[0016] Another object of the present disclosure is to provide a system and method(s) that can preclude the rework for sluggish contact & loose contact assembly.
[0017] Another object of the present disclosure is to reduce the cycle time & increase the productivity.
[0018] Various objects, features, aspects and advantages of the present invention will become more apparent from the detailed description of the invention herein below along with the accompanying drawing figures in which like numerals represent like components.

SUMMARY
[0019] The disclosure generally relates to low voltage electrical power systems. In particular, it pertains to an automated system for low voltage electrical switchgears to check and remove contact sluggishness by fastening the lower contact and terminal joint of a switchgear based on closed loop feedback system based on value of voltage drop (mV) monitored in real time, thereby increasing the reliability and productivity of the system.
[0020] In an aspect, the present disclosure provides an automated system for fastening a contact in a switchgear, the automated system includes: a contact fastening means; a voltage drop (mV) measurement means for measuring a value of voltage drop (mV) for said contact; and a logic circuit; wherein the logic circuit commands said contact fastening means to tighten or loosen the contact based on the measured value of voltage drop (mV). In an embodiment, the logic circuit commands said contact fastening means to tighten the contact in case the measured value of voltage drop (mV) is higher than a pre-determined upper threshold. In an embodiment, the logic circuit commands said contact fastening means to loosen the contact in case the measured value of voltage drop (mV) is lower than a pre-determined lower threshold. In an embodiment, the logic circuit commands said contact fastening means to tighten the contact in case the measured value of voltage drop (mV) is higher than 0.55 mV and wherein the logic circuit commands said contact fastening means to loosen the contact in case the measured value of voltage drop (mV) is lower than 0.5 mV. In an embodiment, the automated system further comprises a contact sluggishness checking means. In an embodiment, the contact sluggishness checking means comprises a pneumatic cylinder and a sensor, wherein the pneumatic cylinder presses the contact against a spring and wherein the sensor detects a return movement of said contact to effect measurement of contact sluggishness.
[0021] Another aspect of the present disclosure relates to a method for fastening a contact in a switchgear, the method including the steps of: measuring a value of voltage drop (mV) for said contact; and tightening or loosening said contact based on the measured value of voltage drop (mV) for said contact. In an embodiment, said contact is tightened in case the measured value of voltage drop (mV) is found to be higher than a pre-determined upper threshold and wherein said contact is loosened in case the measured value of voltage drop (mV) for said contact is found to be lower than a pre-determined lower threshold. In another embodiment, said contact is tightened in case the measured value of voltage drop (mV) is found to be higher than 0.55 mV and wherein said contact is loosened in case the measured value of voltage drop (mV) for said contact is found to be lower than 0.50 mV. In still another embodiment, the method further includes the steps of: measuring a value for sluggishness of said contact; verifying the measured value for sluggishness of said contact within a pre-determined sluggishness threshold; measuring a value of voltage drop (mV) for said contact; and verifying the measured value of voltage drop (mV) for said contact to be between 0.50 mV and 0.55 mV.
[0022] Various objects, features, aspects and advantages of the inventive subject matter will become more apparent from the following detailed description of preferred embodiments, along with the accompanying drawing figures in which like numerals represent like components.

BRIEF DESCRIPTION OF THE DRAWINGS
[0023] The accompanying drawings are included to provide a further understanding of the present disclosure, and are incorporated in and constitute a part of this specification. The drawings illustrate exemplary embodiments of the present disclosure and, together with the description, serve to explain the principles of the present disclosure.
[0024] FIG. 1A illustrates an exemplary side view of a stepper motor assembly in accordance with embodiments of the present disclosure.
[0025] FIG. 1B illustrates an exemplary perspective view of a stepper motor assembly in accordance with embodiments of the present disclosure.
[0026] FIG. 2A illustrates an exemplary perspective view of mV measurement probes & screw driver assembly in accordance with embodiments of the present disclosure.
[0027] FIG. 2B illustrates an exemplary top view of mV measurement probes & screw driver assembly in accordance with embodiments of the present disclosure.
[0028] FIG. 3 illustrates an exemplary front view of a loading station assembly with switchgear loaded onto it in accordance with embodiments of the present disclosure.
[0029] FIG. 4 illustrates an exemplary flowchart depicting working of the automated system for fastening a contact in switchgear in accordance with embodiments of the present disclosure.

DETAILED DESCRIPTION
[0030] The following is a detailed description of embodiments of the disclosure depicted in the accompanying drawings. The embodiments are in such detail as to clearly communicate the disclosure. However, the amount of detail offered is not intended to limit the anticipated variations of embodiments; on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present disclosure as defined by the appended claims.
[0031] Each of the appended claims defines a separate invention, which for infringement purposes is recognized as including equivalents to the various elements or limitations specified in the claims. Depending on the context, all references below to the “invention” may in some cases refer to certain specific embodiments only. In other cases it will be recognized that references to the “invention” will refer to subject matter recited in one or more, but not necessarily all, of the claims.
[0032] As used in the description herein and throughout the claims that follow, the meaning of “a,” “an,” and “the” includes plural reference unless the context clearly dictates otherwise. Also, as used in the description herein, the meaning of “in” includes “in” and “on” unless the context clearly dictates otherwise.
[0033] All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g. “such as”) provided with respect to certain embodiments herein is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention otherwise claimed. No language in the specification should be construed as indicating any non-claimed element essential to the practice of the invention.
[0034] Various terms as used herein are shown below. To the extent a term used in a claim is not defined below, it should be given the broadest definition persons in the pertinent art have given that term as reflected in printed publications and issued patents at the time of filing.
[0035] The disclosure generally relates to low voltage electrical power systems. In particular, it pertains to an automated system for low voltage electrical switchgears to check and remove contact sluggishness by fastening the lower contact and terminal joint of a switchgear based on closed loop feedback system based on value of voltage drop (mV) monitored in real time, thereby increasing the reliability and productivity of the system.
[0036] In an aspect, the present disclosure provides an automated system for fastening a contact in a switchgear, the automated system includes: a contact fastening means; a voltage drop (mV) measurement means for measuring a value of voltage drop (mV) for said contact; and a logic circuit; wherein the logic circuit commands said contact fastening means to tighten or loosen the contact based on the measured value of voltage drop (mV). In an embodiment, the system continuously monitors the value of voltage drop (mV) during tightening or loosening said contact by said contact fastening means. In an embodiment, the logic circuit commands said contact fastening means to tighten the contact in case the measured value of voltage drop (mV) is higher than a pre-determined upper threshold. In an embodiment, the logic circuit commands said contact fastening means to loosen the contact in case the measured value of voltage drop (mV) is lower than a pre-determined lower threshold. In an embodiment, the pre-determined upper threshold can be 0.55 mV. In an embodiment, the pre-determined lower threshold can be 0.50 mV. However, a person skilled in the art would appreciate that the pre-determined upper threshold and the pre-determined lower threshold can be any other value to serve the specific needs. In an embodiment, the logic circuit commands said contact fastening means to tighten the contact in case the measured value of voltage drop (mV) is higher than 0.55 mV and wherein the logic circuit commands said contact fastening means to loosen the contact in case the measured value of voltage drop (mV) is lower than 0.50 mV. In an embodiment, the automated system further comprises a contact sluggishness checking means. In an embodiment, the contact sluggishness checking means comprises a pneumatic cylinder and a sensor, wherein the pneumatic cylinder presses the contact against a spring and wherein the sensor detects a return movement of said contact to effect measurement of contact sluggishness.
[0037] The advantageous system and method(s), realized in accordance with embodiments of the present disclosure, can be used for any switchgear(s) including but not limited to any circuit breakers like a miniature circuit breaker (MCB), a moulded case circuit breaker (MCCB), a residual current device (RCD), residual current breaker with overload protection (RCBO), an earth leakage circuit breaker (ELCB), a recloser, a polyswitch, a magnetic circuit breaker or any other protection device(s) known to a person skilled in the art wherein the voltage drop across a contact should be within the specified limits to ensure satisfactory functionality and long service life of said protection device.
[0038] In an embodiment, the contact fastening means can include a fastener holding and fastening means including any or a combination of a screw driver bit, a nut holding and/or fastening means and the like as known to a person skilled in the art. In an embodiment, the contact fastening means can also include a means to provide necessary driving force to said fastening means including stepper motor and the like as known to a person skilled in the art. In an embodiment, the contact fastening means can be operatively coupled to the means to provide necessary driving force to said fastening means. In an embodiment, a screw driver bit can be operatively coupled to the stepper motor. In an embodiment, a nut holding means can be operatively coupled to the stepper motor. In an embodiment, a screw driver bit can be operatively coupled to first stepper motor and a nut holding means can be operatively coupled to a second stepper motor Alternatively, the fastener holding and fastening means can be integrally formed with the means to provide necessary driving force to said fastening means.
[0039] In an embodiment, the voltage drop measurement means can include any of the electronics known to a person skilled in the art to serve its indented purpose to measure voltage drop across a joint or a contact. In a preferred embodiment, the voltage drop measurement means can include any Millivolt Drop Tester known to a person skilled in the art.
[0040] In an embodiment, the logic circuit can include any logic device with decision making ability to its serve its intended purpose in accordance with embodiments of the present invention.
[0041] Another aspect of the present disclosure relates to a method for fastening a contact in a switchgear, the method including the steps of: measuring a value of voltage drop (mV) for said contact; and tightening or loosening said contact based on the measured value of voltage drop (mV) for said contact. In an embodiment, the value of voltage drop (mV) is continuously monitored during said tightening or loosening of said contact. In an embodiment, said contact is tightened in case the measured value of voltage drop (mV) is found to be higher than a pre-determined upper threshold and wherein said contact is loosened in case the measured value of voltage drop (mV) for said contact is found to be lower than a pre-determined lower threshold. In an embodiment, the pre-determined upper threshold can be 0.55 mV. In an embodiment, the pre-determined lower threshold can be 0.50 mV. However, a person skilled in the art would appreciate that the pre-determined upper threshold and the pre-determined lower threshold can be any other value to serve the specific needs. In an embodiment, said contact is tightened in case the measured value of voltage drop (mV) is found to be higher than 0.55 mV and wherein said contact is loosened in case the measured value of voltage drop (mV) for said contact is found to be lower than 0.50 mV. In another embodiment, the method further includes the steps of: measuring a value for sluggishness of said contact; verifying the measured value for sluggishness of said contact within a pre-determined sluggishness threshold; measuring a value of voltage drop (mV) for said contact; and verifying the measured value of voltage drop (mV) for said contact to be between 0.50 mV and 0.55 mV.
[0042] In an embodiment, the system can include three major assembly units namely a stepper motor assembly, mV measurement probes & screw driver assembly and a loading station assembly. In an embodiment, the stepper motor assembly can include a stepper motor and a hex nut slot. In another embodiment, the stepper motor assembly can further include a linear pneumatic cylinder to check and remove contact sluggishness. Figure 1A illustrates an exemplary side view 100 and Figure 1B illustrates an exemplary perspective view 150 of a stepper motor assembly, realized in accordance with embodiments of the present disclosure. In an embodiment, the stepper motor assembly can include a 1kW stepper motor 102, a hex nut slot 106 and a linear pneumatic cylinder 104. The pneumatic cylinder 104 can be fitted with a nylon part at the end to make sure that the fixed contact button is not damaged during use. The hex nut slot can have a provision to accommodate the M3 hex nut of the assembly (switchgear). Once the nut of the assembly is inside the slot, the rotation of the stepper motor rotates the nut, thereby fastening or loosening the assembly (switchgear) as required.
[0043] Figure 2A illustrates an exemplary top perspective view 200 and Figure 2B illustrates an exemplary top view 250 of the mV measurement probes & screw driver assembly, realized in accordance with embodiments of the present disclosure. In an embodiment, the mV measurement probes & screw driver assembly can include linear pneumatic cylinders 202 and 204. Pneumatic cylinder 202 can detachably engage a screw driver bit 206. The screw driver bit 206 can hold on to the screw of the assembly (switchgear) so that when the stepper motor 102 (of stepper motor assembly as illustrated in Figures 1A and 1B) rotates the hex nut, it does not allow the screw to rotate as well, thus completing the fastening operation. The second pneumatic cylinder 204 can be connected to a block 208 that can house the mV measurement probes 210, 212, 214 and 216. The second pneumatic cylinder 204 can serve the function of pushing the block 208 forward so that probes 214 and 216 can touch the terminal while probes 210 and 212 touches the moving contact. This arrangement can enable the precise measurement of voltage drop (measurement of mV) at the fastening joint (contact) of the 2 parts. The block 208 including the probes 210, 212, 214 and 216 can be guided with guiding rods 218, so that the probe can touch the exact location on the assembly (switchgear) every time and reduces the errors in measurement.
[0044] Figure 3 illustrates an exemplary front view 300 of a loading station assembly with exemplary switchgear loaded onto it, realized in accordance with embodiments of the present disclosure. In an embodiment, the switchgear can include a lower contact 304, a terminal 306 and a spring 308. In an embodiment, the loading station assembly can include a linear pneumatic cylinder 302 that can provide limited extension to the lower contact 304 of the switchgear, so that every switchgear can undergo the same measurement and fastening process, every time.
[0045] In accordance with embodiments of the present disclosure, the three major assembly units namely a stepper motor assembly (as illustrated in Figures 1A and 1B), mV measurement probes & screw driver assembly (as illustrated in Figures 2A and 2B) and a loading station assembly (as illustrated in Figure 3) can be operatively coupled to each other to serve its intended purpose in accordance with the present disclosure.
[0046] In operation, once the switchgear is loaded on the loading station assembly, the pneumatic cylinder 302 can lift the lower contact 304 to aid in the measurement process. The voltage drop (mV) measurement probes & screw driver assembly can then be actuated and the screw driver bit 206 can move forward by the pneumatic cylinder 202. Further, on activation, the pneumatic cylinder 204 can push the block 208 forward so that the probes 210 and 212 can touch the moving contact 304 and the probes 214 and 216 can touch the terminal 306. As soon as the probes touch the moving contact 304 and the terminal 306, the measurement of voltage drop (mV value) can be carried out. The measured value(s) of mV (voltage drop) can be displayed on a display device (e.g. screen or any other device known to a person skilled in the art). Further, measured value(s) of mV (voltage drop) can be transferred to the internal logic (e.g. a logic circuit known to a person skilled in the art) to provide a command to the stepper motor 102 based on the measured value(s) of mV (voltage drop). The rotation and the direction of the rotation of stepper motor depends on the command from the internal logic, which in turn depend on the measured value(s) of mV (voltage drop). If the measured value(s) of mV (voltage drop) is found to be higher than the pre-determined upper threshold (e.g. 0.55 mV), the internal logic can issue a command to the stepper motor to start rotating in clockwise direction to tighten the nut. If the measured value(s) of mV (voltage drop) is found to be lower than the pre-determined lower threshold (e.g. 0.50 mV), the internal logic can issue a command to the stepper motor to start rotating in anti-clockwise direction to loosen the nut. Further, as the stepper motor rotates either in the clockwise or the anti-clockwise direction to tighten or loosen the nut, the mV (voltage drop) measurement probes measures the value(s) of mV (voltage drop) in real-time (e.g. mV value can be monitored continuously or intermittently) and the measured values are provided to the internal logic to issue commands to the stepper motor accordingly. In this way, speed of stepper motor 102 can be synchronized to the mV (voltage drop) value of the system, measured in real-time. If the mV value of the switchgear is coming nearer to threshold (lower or upper), motor speed can be reduced to achieve mV value towards mean of the thresholds. If the mV value falls within range (e.g. 0.50 mV to 0.55 mV), the internal logic issues command to the stepper motor to stop the rotation. This can be followed by disconnection of mV measuring probes (210, 212, 214 and 216) and initiation of contact sluggishness measurement. During contact sluggishness measurement, the pneumatic cylinder 104 of stepper motor assembly unit can press the lower contact 304 for a predefined number of times (e.g. five times) against the spring 308, and the return movement of the moving contact can be detected by a sensor (e.g. a laser sensor) to measure the sluggishness in the contact. If the contact sluggishness is found to be within the pre-determined sluggishness threshold, the value of mV is verified again. If the measured value of mV falls within the acceptable range (e.g. between 0.50 mV and 0.55 mV), the assembly is passed. If the mV value falls outside the acceptable range (between 0.50 mV and 0.55 mV), then the system repeats the cycle as described above for a predefined number of times (e.g. 5 times) to achieve the desired value of mV (voltage drop).
[0047] Figure 4 illustrates an exemplary flowchart 400 depicting working of the automated system, realized in accordance with embodiments of the present disclosure, for fastening a contact in switchgear. In an embodiment, once the switchgear is loaded on the loading station assembly, the pneumatic cylinder 302 can lift the lower contact 304 to aid in the measurement process. The voltage drop (mV) measurement probes & screw driver assembly can then be actuated and the screw driver bit 206 can move forward by the pneumatic cylinder 202. Further, on activation, the pneumatic cylinder 204 can push the block 208 forward so that the probes 210 and 212 can touch the moving contact 304 and the probes 214 and 216 can touch the terminal 306. As soon as the probes touch the moving contact 304 and the terminal 306, the measurement of voltage drop (mV value) can be carried out. The measured value(s) of mV (voltage drop) can be displayed on a display device (e.g. screen or any other device known to a person skilled in the art). Further, measured value(s) of mV (voltage drop) can be inputted to the internal logic (e.g. a logic circuit known to a person skilled in the art) as shown at the step 402. The internal logic then compares the measured mV value with the predetermined upper and/or lower threshold as shown at the step 404 to issue a command to the stepper motor 102 based on the measured value(s) of mV (voltage drop). If the measured value(s) of mV (voltage drop) is found to be higher than the pre-determined upper threshold (e.g. 0.55 mV), the internal logic can issue a command to the stepper motor to start rotating in clockwise direction to tighten the nut as shown at the step 406. If the measured value(s) of mV (voltage drop) is found to be lower than the pre-determined lower threshold (e.g. 0.50 mV), the internal logic can issue a command to the stepper motor to start rotating in anti-clockwise direction to loosen the nut as shown at the step 408. Further, as the stepper motor rotates either in the clockwise or the anti-clockwise direction to tighten or loosen the nut, the mV (voltage drop) measurement probes measures the value(s) of mV (voltage drop) in real-time (e.g. mV value can be monitored continuously or intermittently) and the measured values are provided to the internal logic to issue commands to the stepper motor accordingly. When the mV value falls within range (e.g. 0.50 mV to 0.55 mV), the internal logic issues command to the stepper motor to stop the rotation. This step is followed by disconnection of mV measuring probes (210, 212, 214 and 216) and initiation of contact sluggishness measurement as shown at the step 410. During contact sluggishness measurement, the pneumatic cylinder 104 of stepper motor assembly unit can press the lower contact 304 for a predefined number of times (e.g. five times) against the spring 308 as shown at the step 412, and the return movement of the moving contact can be detected by a sensor (e.g. a laser sensor) to measure the sluggishness in the contact as shown at the step 414. If the contact sluggishness is found to be within the pre-determined sluggishness threshold, the value of mV is verified again as shown at the step 416. If the measured value of mV falls within the acceptable range (e.g. between 0.50 mV and 0.55 mV), the assembly is passed, as shown at the step 418. If the mV value falls outside the acceptable range (between 0.50 mV and 0.55 mV), then the cycle is repeated as shown at the step 420 for a predefined number of times (e.g. 5 times) to achieve the desired value of mV (voltage drop).

[0048] While the foregoing describes various embodiments of the invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof. The scope of the invention is determined by the claims that follow. The invention is not limited to the described embodiments, versions or examples, which are included to enable a person having ordinary skill in the art to make and use the invention when combined with information and knowledge available to the person having ordinary skill in the art.

ADVANTAGES OF THE INVENTION
[0049] The present disclosure overcomes one or more disadvantages associated with conventional methods and systems for fastening lower contacts with the terminal in switchgears.
[0050] The present disclosure provides for a system and method(s) to automate fastening of lower contacts with the terminal in switchgears.
[0051] The present disclosure provides for a system and method(s) to reduce the time required for assembling the switchgear.
[0052] The present disclosure provides for a system and method(s) that can enable a user to achieve better control over the milli-volt value.
[0053] The present disclosure provides for a system and method(s) that can preclude the rework for sluggish contact & loose contact assembly.
[0054] The present disclosure provides for a system and method(s) to reduce the cycle time & increase the productivity.