Three Phase Voltage Regulating Device

THREE-PHASE VOLTAGE REGULATING DEVICE FIELD OF THE INVENTION This invention relates to a three-phase voltage regulating device. More particularly the present invention relates to a new and improved servo motor operated three-phase constant voltage stabilizer for uneven load and unbalanced voltage. BACKGROUND OF THE INVENTION Imbalance of phase voltages in three phase systems has long been a problem. The voltage fluctuation is very harmful for end use equipments, which may get totally damaged or ma1 function. In production units or factories, whole production chain suffers and business losses are compounded on multiple fronts. Wfih variation in voltage, energy loss also increases. A switching regulator provides a regulated output voltage to a load from an unregulated input voltage; these are intended to be efficient for converting a power source from one form to another. A few common switching regulators used are Boost, where output voltage is greater than input voltage and Buck where output voltage is less than input voltage, regulators. Using the buck boost regulators several types of servo motor operated 3-phase constant voltage stabilizer have been developed. These arrangements make use of buck boost with dimmer, double-wound dimmerstat or are linear in construction to replace dimmerstat. Use of buck boost and dimmerpr dimmer alone, increases the on load and load losses in the stabilizer at continuous worst load conditions. There are various existing devices in the market such as a device using dimmer and buck boost assembly, wherein a carbon brush (es) moves on the periphery of dimmer. Input supply is given to dimmer. Servo motor mechanism controls the movement of carbon bush over the dimmer and based on the input voltage, current is fed to the primary winding of buck boost transformer which increased decreases the output voltage to desired limit. Further.for 3-phase supply, three such devices are used. This type of device uses more copper, core and other material. Its efficiency is also low due to more no load and load losses. Another kind of devices has double wound dimmer, a dimmer has double layer winding. On outer winding, carbon brush moves in similar way as in device disclosed above. In this design PATENTISELHI 29-07-20P6 17: 0 2 also losses are more and it has capacity limitation due to low heat dissipation of inner winding layer. One another device used is a linear type device, where 3 limb cores are used for 3-phase supply. Each limb has two1 multi-layer windings which are attached with buck boast. Two sets of carbon brushes are used for each winding. One carbon b~sihs u sed for low input voltage and other is used for high input voltage. Such devices are suitable only for balanced voltage on all phases. They use more material and have high no load losses. These days emphasis is being given to high efficiency electrical equipment at an affordable cost. Presently, the type of stabilizers available in the market, are either not very efficient or are unable to properly handle unbalanced load conditions. They are bulky, use more material and thus are costly to install and maintain. To overcome the limitations associated with existing arts, there is a need to develop high efficient equipment for maintaining constant voltage to save energy. SUMMARY OF THE INVENTION To overcome limitations in the prior art, and to overcome other limitations that will become apparent upon reading and understanding the present specification, the present invention discloses a system for a three-phase voltage regulating device. In accordance with one embodiment of the invention, it provides a voltage regulating device that includes a winding, at least one carbon brush providing a voltage input to the winding, a chainsprocket arrangement and the carbon brush coupled to the chain-sprocket arrangement, a servo motor that is used to control the carbon brush. The voltage regulating device is an auto transformer, and is configured to work in an alternating current power system. In one embodiment, a voltage regulating device has a winding comprising an inner and an outer winding, the inner winding has a number of tums based on low input voltage and the outer winding has a number of tums based on a difference of high input voltage and low input voltage. In another embodiment, a voltage regulating device has a winding where cross section of an inner winding is selected based on a net current at full load low voltage input current minus full P A T E N T D E L H I 29-07-20?6 1 7 : 02 load output current and cross section of an outer winding is selected based on full load output current. In another embodiment, a voltage regulating device has a winding comprising a multi layer inner winding and a single layer outer winding. In yet another embodiment, a voltage regulating device has a winding comprising a single layer inner winding and a single layer outer winding. In one another embodiment, a voltage regulating device comprising, a contmller to control the movement of the carbon brush as per inputl output voltage limits. In one embodiment, a voltage regulating device comprising, a voltage output from a fixed tapping on the winding, wherein the output tapping is taken from a tum of an outer winding which corresponds to output voltage. In another embodiment, a voltage regulating has output tapping points which are joined in h Q, parallel with a balance coil in between, wherein the balance coil takes care of any voltage m m variation at output tapping points of windings two limb. n -a .u-. In another embodiment, a voltage regulating device has a voltage input is given to the winding + V N of each limb through at least one carbon brush which moves axially over the winding. -. S In another embodiment, a voltage regulating device is a three phase auto transformer, L L 0 comprising of three single phase auto transformers for connecting phases. L V) 7 0 In one another embodiment, a voltage regulating device sends1 receives instructions to1 from an 7 online voltage monitoring tool. - n -I In one another embodiment, a voltage regulating device is an auto transformer based voltage in regulating device and achieves higher efficiency to that of a buck boost based arrangement, M (V -- 7 CO In one another embodiment, a voltage regulating device is an auto transformer based voltage b M regulating device and achieves higher efficiency to that of a dimmer based arrangement. M 0 v- PATENTDELHI 2 9 - 0 7 - 2 0 1 3 6 1 7 : 0 2 3 - In another embodiment, a voltage regulating device has efficiency of the order of 97%-99% In one embodiment, a voltage regulating device has a single layer or multi layered inner winding and a single layer outer winding. These windings are connected in series. Innerwinding has I number of turns based on low input voltage. Outer winding has a number of turns based on a difference of high input voltage and low input voltage. In one another embodiment, a voltage regulating device has a winding where cross section of inner layer (s) is selected based on a net current at full load low voltage input current minus full load output current and cross section of outer layer is selected based on full load output current. One another embodiment of the present invention provides a voltage regulating device that includes a voltage stabilizer having at least three cores where each core is a two limb mitered core, a two layer spiral winding on both legs of each core, the layers of the winding are connected in series. The windings of both legs are connected in parallel and the voltage regulating device is a three phase auto transformer. In one another embodiment, a voltage regulating device has the mitered cores which are made of CRGO material having low losses. In one embodiment, a voltage regulating device has hndings which are connected to flow a flux in the respective core in same (i.e. either clock-wise of anti-clock-wise) direction and flux density in the respective core is proportionate to input voltage. In another embodiment, a voltage regulating device comprising a voltage input applied from a source for selectively stepping up or down output voltage to a load. In another embodiment, a voltage regulating device comprising a voltage output taken from tapping points which are joined in parallel with a balance coil in between, wherein the balance coil takes care of any voltage variation at output tapping points. In one another embodiment, a voltage regulating device has winding comprising a stepped core. In yet another embodiment, a voltage regulating device comprising a controller, wherein the controller regulates an output voitage. P A T E W T D E L H I 29-07-20146 17: 02 These and various other advantages and features of novelty which characterize the invention are pointed out with greater particularity in the claims annexed hereto and form a part hereof. However, for a better understanding of the invention, its advantages, and the objects obtained by its use, reference should be made to the drawings which form a further part hereof, and to accompanying descriptive matter, in which there are illustrated and described specific examples of a system and method in accordance with the invention. BRIEF DESCRIPTION OF THE DRAWINGS A clear understanding of the key features of the invention summarized above may be had by reference to the appended drawings, which illustrate the method and system of the invention, although it will be understood that such drawings depict preferred embodiments of the invention and, therefore, are not to be considered as limiting its scope with regard to other embodiments which the invention is capable of contemplating. Accordingly: FIG. 1 illustrates an exemplary voltage regulating unit system, according to one embodiment of the invention. FIG. 2 illustrates an exemplary voltage regulating unit system, according to another embodiment of the invention. FIG. 3 is a circuit diagram illustrating thecirwit constitution of the voltage switching regulator, when supply is at low input volt, in an embodiment of the present invention; FIG. 4 is a circuit diagram illustrating the circuit constitution of the voltage switching regulator, when supply is at high input volt, in an embodiment of the present invention; FIG. 5 illustrates an exemplary voltage regulating unit system, according to one another embodiment of the invention. DETAILED DESCRIPTION OF THE INVENTION In the following, reference is made to embodiments of the invention. However, it should be understood that the invention is not limited to specific described embodiments. Instead, any combination of the following features and elements, whether related to different embodiments or not, 'is contemplated to implement and practice the invention. Furthermore, in various embodiments the invention provides numerous advantages over the state of the arts. However, although embodiments of the invention may achieve advantages over other possible solutions and1 or over the state of the art, whether or not a particular advantage is achieved by a given embodiment is not limiting of the invention. PATENTDELH.~ 29-07'-201'6 17: 02 Thus, the following aspects, features, embodiments and advantages are merely illustrative and are not considered elements or limitations of the appended claims except where explicitly recited in claims. Similarly, reference to the invention shall not be ~0nst~eads a generalization of any inventive subject hatter disclosed herein and shall not be considered to be an element or limitation of the appended claims except where explicitly recited in claims. It is the principal object of the present invention to provide an improved auto transformer based three phase voltage regulating device, which is designed for extreme voltage variations and capable of managing unbalanced or uneven load and unbalanced voltage. It is a further object of the invention to provide an improved three phase voitage regulating device, which is a servo motor operated device and is buck boost free and capable of maintaining constant voltage to save energy. It is a still further object of the present invention to provide an improved three phase voltage regulating device which is highly efficient and developed at affordable cost. h d) Embodiments of the present inyention provides a structure with less number of components, cn m fewer and less quantity of materials used in manufacturing of the regulator. Further, the L assembly of the components is easier and relativety less skill dependent. It also takes less time -a .u- to manufacture. ' -+ - N E Various embodiments of the present invention eliminate the possibility of failure due to buck L 0 boast or dimmer as earlier. The arrangement is completely free from Buck boost or dimmer L \ principles thus the losses observed are less, especially under no-load conditions high savings V) 7. are observed. 0 9 It is an object of the invention to provide a better efficiency to that of a buck boost based or dimmer based regulatory arrangement. Further, the efficiency target is to provide an efficiency 7. V) of the order 97% to 99% in comparison to other existing system where the efficiency is 95% to M N 97%. 7 CO b M It is also an object of the invention to provide better heat dissipation arrangement for saving the M (D - device from excess heat based failures. 0. -9 PATEIJTDELHI 2 9 - 0 7 - 2 0 8 6 1 7 : 0 2 3 It is an object of the invention to provide an arrangement where it is possible to regulate the voltage from 200-520 volts to 40014151433 volt with a low impedance. It is an object of the invention to provide a voltage regulating device has winding comprising a stepped core in a radial cross section. Embodiments of the invention provide high efficiency, low cost, low maintenance and less space requirement. The devices are equally useful in hotels, hospitals, multi-storied buildings, mobile towers, shopping malls, cinemas, factories where CNC machines are used, closely-knit colonies and also in other big areas. This is possible due to low cost, high efficiency, easy customization and fast assembly. It is also an object of the invention to provide a structure with two layer windings which is put on the multiple limbs for high voltage1 precision requirements and similar structure with windings on one limb for smaller rating stabilizers in same fashion. It is also an object of the invention to provide a structure with one winding on each limb for high capacity requirements and similar structure with one winding on only one limb for smaller rating stabilizen in same fashion. The above and other objects of the present invention are achieved by employing an auto transformer concept which eliminates the use of buck boost and dimmer, this in-tum reduces the cost, size, and increases the efficiency. Thus, embodiments of the invention may significantly reduce application development and. overhead costs. One of ordinary skill in the art will readily recognize, however, that embodiments of the invention may be adapted for use with a wide variety of applications, .in different platforms, structures, arrangements. FIG. 1 illustrates an exemplary voltage regulating unit system 100 where an input voltage 102 is supplied to a voltage regulating unit 104. The input voltage 102 can be uneven due to varying loads, fluctuations, deterrent supply structure or other reasons. The voltage regulating unit 104 regulates the voltage using one. of the embodiments of the present invention and supplies an output voltage 106. A controller 108 controls the movement of the components within the voltage regulating unit 104 and helps in overall functioning of the voltage regulating unit 104. The controller 108 can be an electronic controller which is a microprocessor based controller having instructions to perform similar to various other types of voltage controllers. Intelligent monitoring and control of the components of the voltage regulating unit 104 is performed using the contmller 108. The contmller has a set of predefined instructions as embedded by the manufacturer or can have a contmller interface 110 which interacts with a user to set the instructions for the 'voltage regulating unit 104. The function of the controller 108 is thus to control the voltage in the volage regulating unit 104. In another embodiment for a three-phase voltage supply structure the voltage regulating unit system 100 has three voltage regulating units 104a, 104b, 104c for the respective phases. The respective input voltage 102 (a, b, or c) is supplied to a voltage regulating unit 104 (a, b, or c) respectively. The input voltage 102 can be uneven due tovarying loads, fluctuations, deterrent supply structure or other reasons. The respedive voltage regulating unit 104(a, b, or c) regulates the voltage using one of the embodiments of the present invention and supplies an output voltage 106. For each phase, a separate voltage stabilizer is made, so that voltage of each phase is corrected individually. . . A single controller 108 controls the movement of the components within the three phase structure of the voltage regulating unit 104 (a, b, or c) and helps in overall functioning of the voltage regulating unit 104 (a, b, or c). The controller 108 can be an electronic controller which is a microprocessor based controller having instructions to perform similar to various other types of voltage controllers. Intelligent .monitoring and control of the components of the voltage regulating unit 104 (a, b, or c) is performed using the controller 108. The controller has a set of predefined instruction set for the three phases as embedded by the manufacturer or can have a controller interface 110 which interacts with a user to set the instructions for the three-phase voltage regulating unit 104 (a, b, or c). The function of the controller 108 is thus to control the voltage for all three phases of the voltage regulating unit 104 (a, b, or c) PATENTDELHI 2 9 - 0 7 - 2 0 9 6 17: 02 FIG. 2 illustrates an exemplary voltage regulating unit system 200 where the input voltage 102 is supplied to the voltage regulating unit 104. The voltage regulating unit 104 regulates the voltage using one of the embodiments of the present invention and supplies the output voltage 106. The voltage regulating unit 104 has a servo motor 204, which controls the movement of a chainsprocket arrangement 206. The movement of the chain-sprocket arrangement 206 moves a carbon brush (es) 208. The input voltage 102 is fed in outer layer of the winding with two limbs, of a core and windings component 202, through 'axially movable carbon brush (es) 208. The carbon brush(es) 208 of both the limbs are connected in parallel. Two limit switches are provided so that the carbon brush (es) 208 does not over shoot the desired limits. Control of movement of the carbon brush (es) 208 is regulated by the controller 108. Two output points on windings of both the limbs are joined in parallel with a balance coil 210 in between, the balance coil 210 takes care of any voltage variation at output points of both limbs and provides the output voltage 106. In another embodiment for a three-phase voltage supply structure the voltage regulating unit system 200 has three voltage regulating units lWa, 104b, 104c for the respective phases. The respective input voltage 102 (a, b, or c) is supplied to a voltage regulating unit 104 (a, b, or c) respectively. For each phase, a separate voltage stabilizer is made, so that voltage of each phase is corrected individually. The voltage regulating unit 104 (a. b, or c) has a phase respective servo motor 204 (a, b, or c). which controls the movement of respective chain-sprocket arrangement 206 (a, b, or c). The movement of the chain-sprocket arrangement 206 (a, b, or c) moves a carbon brush (es) 208 (a, b, or c). The input voltage 102 is fed in outer layer of the winding with two limbs (three such pairs, each respective to one phase), of a respective core and windings component 202 (a, b, or c), through axially movable carbon brush (es) 208(a, b, or c). The carbon brush(es) 208 (a, b, or c) of both the limbs are connected in parallel. Two limit switches (to each phase) are provided so that the carbon brush (es) 208 (a, b, or c) does not over shoot the desired limits. Control of movement of the carbon brush (es) 208 (a,'b, or c) is regulated by a single controller 108. Two output points (to each phase windings) of both the limbs are joined in parallel with a balance coil P A T E N T Q E L H I 2 9 - 0 7 - 2 0 8 6 17: 0 2 210 (a, b, or c) to each phase in between, the balance coil 210 (a, b, or c) takes care of any voltage variation at output points of both limbs (to each phase) and provides the output voltage 106. FIG. 3 is a circuit diagram illustrating the circuit constitution of the voltage switching regulator, when supply is at low input volt. The voltage regulating unit component 300 shows the internal circuit diagram of the core and windings component such as of 202 (a, b, c) in one of the embodiments. Each of the voltage regulating unit 104 is a voltage stabilizer and has a two limb mitered cores (one of 302a1, other of 302a2) made of CRGO electrical sheet steel. Flux density in the core is chosen in such a way so that core does not get saturated even at highest input voltage. The two limb cores will be separate for all three phases (totaling 3 pain of two cores in a 3-phase structure). A two layer winding (302al. 302a2) is put on the each limb. In case of smaller rating stabilizers winding is put only on one limb. Decision to put winding on one' limb or on both limbs depends upon the capacity of stabilizer and current rating of the carbon brush(es) 208. The number of turns in each winding corresponds to higher input voltage requirement. Volt per turn is normally taken as 1-1.2. Number of tums in inner layer corresponds to lower voltage requirement and outer layer has number of tums corresponding to d~fference of higher input voltage and lower input voltage. Cross-section of inner layer is selected based on difference of high input current and output current or low-input current and output current, whichever is more. Whereas, cross-section of outer layer is based upon output current. Inner and outer layen are then connected in series. Circuit diagram shows the flow of current and voltage where lo is Output current, liL is Input current at low input voltage. Two output points (to each phase windings) of both the limbs are joined in parallel with a balance coil 310 (a, b, or c) to each phase in between, the balance coil 310 (a, b, or c) takes care of any voltage variation at output points of both limbs (to each phase) and provides the output current lo. P A T E N T D E L H I 29-07-209'6 17: 02 In this case, windings are provided on both the limbs because maximum input current is more than 60 Amp. Winding on one limb is made in clockwise direction while the winding of other limb is made in anticlockwise direction. For three-phase structure three such winding arrangements will be made respective to each of the phase. FIG. 4 is a circuit diagram illustrating the circuit constiiution of the voltage switching regulator, when supply is at high input volt The voltage regulating unit component 400 shows the internal circuit diagram of the core and windings component such as of 202 (a, b, c) in one of the embodiments. Circuit diagram shows the flow of current and voltage where lo is Output current, liH is Input current at high input voltage. Similar to earlier structure a two layer winding (402al. 402a2) is put on the each limb. Two output points (to each phase windings) of both the limbs are joined in parallel with a balance coil 410 (a, b, or c) to each phase in between, the balance coil 410 (a, b, or c) takes care of any voltage variation at output points of both limbs (to each phase) and provides the output current lo. For three-phase structure three such winding arrangements will be made respective to each of the phase. FIG. 5 illustrates an exemplary voltage regulating unit system 500, according to one another embodiment of the invention. An online monitoring tool 502 communicates with the controller 108 to control the parameten for sending instructions for voltage regulation through the voltage regulation unit 104 (a. b. c). The online monitoring tool 502 also receives inputs for the current state of the voltage regulation unit 104 (a, b, c) through the controller 108. The controller 108 has the necessary components for the online receipt and sending of instructions. The components include a wired or wireless internet connection, relay, sensor units, and other agents for communicating with the sohare installed for the online monitoring tool 502. Data storage 504 keeps a check and record of all the functions and data collected or send time to time. PATENTDELHI 29-07-20i16 1 7 : 02 It is an object of the present invention to reduce the operation & maintenance cost of installed equipment. For this task on-line voltage condition monitoring equipments provide focused. purposeful diagnosis information, so that remedial measures can be initiated for insipient faults.. Equipments work with a standard communication protocol and are linked to server which has powerful analysis sohare to estimate the extent of deterioration and effect of failure on real time basis and thereby forecast any defect or ageing. Among various parameters some of the recorded parameters are winding temperature, output voltage and controller performance, continuous log of voltage & current on all three phases, peak demand conditions, etc. With the help of these tools we can prepare the graphical representations which will be useful for data analysis and will help in planning preventive. maintenance schedules, life estimation and replacementl repair plan, asset life extension by providing analysis & control, maintaining reliability, energy, saving and load management, minimization of the long-term operational cost, cost saving by eliminating the unplanned maintenance, and in time procurement of spare parts to get competitive rates, etc. One of the embodiments have been shown with readings of Single phase. 20 KVA, input voltage 175 to 280 V, and output voltage of 230 V. Calculations: Volt/ turn (taken as) Tums corresponding to low input Tums corresponding to high input Tums corresponding to output voltage Tums in inner layer Tums in outer layer Output tapping from top of outer layer Current at low input Current at High input Output current Winding provided on single1 both limbs Cross-section of inner layer corresponds to Cross-section of outer layer corresponds to 1.1 159 255 209 159 (255-159) = 96 255-209= 46 tums 114.3 Amp 71.43 Amp 86.96 Amp Both (connected in parallel) Higher of {(I1 4.3-86.96)12=13,67) & ((86.96-71.43)12=7.77) i.e. 13.67 Amp 86.9612 = 43.48 Amp P A T E N T D E L H I 29-07-20% 17: 02 In one of the embodiments of the current invention, the data was recorded for the various combinations and following readings were observed. ~ossibleK VA rating, input voltage range and output voltage are as follows: The following tables show that no-load losses are less and efficiency is more in case of , proposed invention as compare to normal voltage stabilizer with buck boost and dimmer. P A T E N T D E L H I 29-07-20136 17: 02 Output Voltage 400 to 433 400 to 433 . 400 to 433 400 to 433 400 to 433 KVA 15-200 15-225 15-240 15-260 15-300 Input Voltage Range 242-520 260-520 280-520 300-520 340-500 Table 1.1 shows the input voltage supplied, output voltage obtained at various KVA readings under No Load Losses, Load Losses. Total Losses conditions and efficiency obtained with dimmer type switching regulator i.e. using dimmer witching regulator arrangement under the already available structures in arts. Auto Transformer Type 7 0 9 J W Table 1.2 shows the input voltage supplied, output voltage obtained at various KVA readings 0 under No Load Losses, Load Losses. Total ~ossesco nditions and efficiency obtained with auto 7 V) transformer type switching regulator i.e. using one of the embodiments of the present invention. M cu 7 CO The t'able 1.2 further shows that the auto transformer based voltage regulating device achieves b M . higher efliciency.to that of a dimmer based arrangement. M (.D 0 9 P A T E N T O E L H I 2 9 - D7-20i46 1 7 : 02 The table 1.2 further also shows that the autotransformer based voltage regulating device has efficiency of the order of 97%-99%. In accordance with a preferred embodiment of this invention, there is provided a voltage regulating device comprising; a winding, a voltage input to' the winding, wherein the voltage input is provided by a carbon bmsh to.the winding and wherein the carbon brush is coupled to a chain-sprocket arrangement and controlled using a servo motor. In accordance with another preferred embodiment of this invention, there is provided a voltage regulating device comprising; a winding, wherein said winding has an inner winding and an outer winding and wherein the inner winding has a number of turns based on low input voltage and the outer winding has a number of tums based on a difference of high input voltage and low input voltage, and wherein cross section of the inner winding is selected based on a net current at full load low voltage input current minus full load output current and cross section of the outer winding is selected based on full load output current and wherein the inner winding can be single layer or multi-layer and the outer winding can be single layer. In accordance with one other prefemd embodiment of the present invention, there is provided a voltage regulating device, wherein said voltage regulating device is a three phase auto transformer, preferably works in an alternating current power system. In accordance with one other preferred embodiment of the present invention, there is provided a voltage regulating device, wherein said voltage regulating device is a three phase auto transformer, preferably works as a stabilizer, wherein the stabilizer is having three two limb mitered cores.of CRGO material. On both legs of each core spiral windings are laid which are connected in series. Windings of both legs are connected in parallel. These windings are made and connected in such a way, so that flux in the core flows in the same direction (i.e. either clockwise or anti clockwise) properly. This type of arrangement eliminates use of auxiliary winding which may otherwise be required for reducing impedance voltage. In accordance with one other preferred embodiment of the present invention, there is provided a voltage regulating device, wherein the winding has a stepped core in radial cross-section and the core is having two legs and wherein on both legs of a core, a two layer spiral windings are laid which are connected in series, windings of both legs are connected in parallel and wherein the voltage input is applied from a source for selectively stepping up1 down output to a load. In accordance with one other preferred embodiment of the present invention, there is provided a voltage regulating device, wherein the winding has a stepped core and the core is having two legs and wherein on both legs of a core, a spiral windings, the layers of which, are connected in series, windings of both legs are connected in parallel and wherein the volage input is applied from a source for selectively stepping up1 down output to a load. In accordance with another embodiment of the present invention, there is provided a voltage regulating device, wherein the carbon brush is also moved manually and wherein the two limit switches are provided so that the carbon brush does not over shoot the desired limits. In accordance with one other preferred embodiment of the present invention, there is provided a voltage regulating device, wherein said voltage regulating device further provides an output from a fixed tapping on the winding and wherein the output tapping is taken from the turn of outer winding which corresponds to output voltage. Input is given to this winding through carbon brush(es) which moves axially over the winding. Movement of carbon brush is through chain and sprocket arrangement and is controlled with the help of servo motor mechanism. Two limit switches are provided so that the carbon brush does not over shoot the desired limits. According to the present invention, the voltage regulating device is developed based on the concept of auto transformer, thereby quantity of major material such as copper, core, oil, steel etc as well as losses are reduced. This in-tum reduces the cost, size, and increases the efficiency. Stepped core in radial cross-section reduces conductor length and copper losses. While the present invention has been described in terms' of particular embodiments and applications, in both summarized and detailed forms, it is not intended that these descriptions in any way limit its scope to any such embodiments and applications, and it will be understood that many substitutions, changes and variations in the described embodiments, applications and details of the method and system illustrated herein and of their operation can be made by those skilled in the art without departing from the spirit of this invention.

We Claim: 1. A voltage regulating device, comprising: a winding; at least one carbon brush, wherein a voltage input to the winding is provided by the carbon brush; a chain-sprocket arrangement, wherein the carbon brush is coupled to the chainsprocket arrangement; a servo motor, wherein the servo motor is used to control the carbon brush; wherein the voltage regulating device is an auto transformer, and is configured to work in an alternating current power system. 2. The voltage regulating device as 'claimed in clai,m 1, wherein the winding further comprises an inner winding and an outer winding, the inner winding has a number of tums based on low input voltage and the outer winding has a number of tums based on a difference of high input voltage and low input voltage. 3. The voltage regulating device as claimed in claim 1, wherein cross section of an inner winding is selected based on a net current at full load low voltage input current minus full load output current and cross section of an outer winding is selected based on full load output current. 4. The voltage regulating device as claimed in claim 1, wherein the winding further comprising a multi layer inner winding and a single layer outer winding. 5. The voltage regulating device as claimed in claim 1, wherein the winding further comprising a single layer inner winding and a single layer outer winding. 6. The voltage regulating device as claimed in claim 1 further comprising, a controller to wntrdl the movement of the carbon brush as per input/ output voltage limits. 7. The voltage regulating device as claimed in claim 1 further comprising, a voltage output from a fixed tapping on the winding, wherein the output tapping is taken from a tum of an outer winding which corresponds to outpj voltage. 8. The voltage regulating device as claimed in claim 8, wherein the output tapping points are joined in parallel with a balance coil in between, wherein the balance coil takes care of any voltage variation at output tapping points. 9. The voltage regulating device as claimed in claim 1, wherein the voltage input is given to the winding through at least one carbon brush which moves axially over the winding. 10. The voltage regulating device as claimed in claim 1, wherein the voltage regulating device is a three phase auto transformer. 1 11. The voltage regulating device as claimed in claim 1,. wherein the voltage regulating device sendl receive instruction to1 from an online voltage monitoring tool. 12. The voltage regulating device' as claimed in claim 1, wherein the voltage regulating device has efticiency of the order of 97%-99%. 13. A voltage regulating device, comprising: a voltage stabilizer, wherein the stabilizer is having: at least three cores, wherein each core is a two limb mitered core; spiral windings on both legs of each core, wherein the layers of the winding are connected in series; wherein the windings of both legs are connected in parallel; wherein the voltage regulating device is a three phase auto transformer. 14. The voltage regulating device as claimed in claim 13, wherein the windings are connected to flow a flux in the respective core in same direction and flux density in the respective core is proportionate to input voltage. 15. The voltage regulating device as claimed in claim 13, further comprising a voltage input applied from a source for selectively stepping up or down output voltage to a load. P A T E N T D E L H I 2 9 - 0 7 - 2 0 1 % 1 7 : 02 .16. The voltage regulating device as claimed in claim 13, further comprising a voltage output taken from tapping points which are joined in parallel with a balance coil in between. wherein the balance coil takes care of any voltage variation at output tapping points. 17. The voltage regulating device as claimed in claim 13, wherein the winding further , . comprising a stepped core.' . .. .. . .. 18. The voltage regulating device as claimed in claim 13, further comprising a controller, ' wherein the controller regulates an output voltage. 19. The voltage regulating device as claimed in claim 13, wherein the voltage regulating device send1 receive instruction to1 from an online voltage monitoring tool. 20. The voltage regulating device as claimed in claim 14, wherein the voltage regulating device has efficiency of the order of 97%-99%.