Claims:
1. A winding arrangement for DC controlled contactor, comprising:
a dual winding configured with a pickup winding and a hold-on winding, wherein the hold-on winding is wound on the pickup winding,
wherein the pickup winding is configured to be short such that, after the contactor is switched on, the hold-on winding and the pickup winding get connected in series.
2. The winding arrangement as claimed in claim 1, wherein the hold-on winding is a low resistance winding and the pickup winding is a high resistance winding.
3. The winding arrangement as claimed in claim 1, wherein the short of the pickup winding takes effect by a delayed NC contact.
4. The winding arrangement as claimed in claim 3, wherein depth of the NC contact ensures that the transition from ‘NC’ to ‘NO’ occurs only after the contact close condition.
5. The winding arrangement as claimed in claim 3, wherein changeover of the delayed NC contact takes place after a certain delay that is translated in terms of bridge travel of the controlled contactor.
6. The winding arrangement as claimed in claim 1, wherein winding of the pickup winding on top of the hold-on winding allows for faster switching due to accelerated cooling.
7. The winding arrangement as claimed in claim 1, wherein direction of winding of the hold-on winding and the pickup winding is same with the direction favoring flux addition.
8. The winding arrangement as claimed in claim 1, wherein coil of the dual wounding configured to be assembled on an fixed magnet that has core shaped as letter “E”.
9. The winding arrangement as claimed in claim 1, wherein resistance of the hold-on winding is lower than the pickup coil.
10. The winding arrangement as claimed in claim 1, wherein resistance of the pickup winding is much higher than the hold-on coil.
, Description:
TECHNICAL FIELD
[0001] The present disclosure generally relates to the field of DC controlled contactors. In particular, the present disclosure pertains to application of normally closed (NC) contacts in DC controlled contactors. More specifically, the present disclosure relates to a winding technique for DC controlled contactors that utilize a delayed NC contact.

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] A contactor can mainly comprise of an electromagnetic coil circuit and a power circuit. When the coil is energized, a moving magnet is attracted to a fixed magnet. This leads to closing of the contact system and thus closes the circuit. But, there have been apprehensions regarding switching frequency, particularly in case of a conventional DC controlled contactor that can be very low due to its huge size.
[0004] There have been efforts in the past to utilize application of a dual winding over core but they provide only limited gains. Particularly, limitations of separating the dual winding over different parts of the core not only lead to less efficient utilization of space but also falls short of ensuring a compact and economical arrangement thereof.
[0005] There is a need in the art to provide a simple, efficient and economical winding arrangement for DC controlled contractors so as to obviate aforementioned shortcomings encountered in the art. Further, it would be an added benefit to enable a construction of coil of control circuit that ensures the contactor to consume lesser power as compared to AC controlled contactor.
[0006] All publications herein are incorporated by reference to the same extent as if each individual publication or patent application were specifically and individually indicated to be incorporated by reference. Where a definition or use of a term in an incorporated reference is inconsistent or contrary to the definition of that term provided herein, the definition of that term provided herein applies and the definition of that term in the reference does not apply.
[0007] In some embodiments, the numbers expressing quantities of ingredients, properties such as concentration, reaction conditions, and so forth, used to describe and claim certain embodiments of the invention are to be understood as being modified in some instances by the term “about.” Accordingly, in some embodiments, the numerical parameters set forth in the written description and attached claims are approximations that can vary depending upon the desired properties sought to be obtained by a particular embodiment. In some embodiments, the numerical parameters should be construed in light of the number of reported significant digits and by applying ordinary rounding techniques. Notwithstanding that the numerical ranges and parameters setting forth the broad scope of some embodiments of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as practicable. The numerical values presented in some embodiments of the invention may contain certain errors necessarily resulting from the standard deviation found in their respective testing measurements.
[0008] 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.
[0009] The recitation of ranges of values herein is merely intended to serve as a shorthand method of referring individually to each separate value falling within the range. Unless otherwise indicated herein, each individual value is incorporated into the specification as if it were individually recited herein. 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.
[0010] Groupings of alternative elements or embodiments of the invention disclosed herein are not to be construed as limitations. Each group member can be referred to and claimed individually or in any combination with other members of the group or other elements found herein. One or more members of a group can be included in, or deleted from, a group for reasons of convenience and/or patentability. When any such inclusion or deletion occurs, the specification is herein deemed to contain the group as modified thus fulfilling the written description of all groups used in the appended claims.
OBJECTS OF THE INVENTION
[0011] A general object of the present disclosure is to provide for a simple, efficient and economical winding arrangement for DC controlled contractors so as to obviate aforementioned shortcomings encountered in the art.
[0012] An object of the present disclosure is to provide a construction of coil of control circuit that ensures DC contactor to consume lesser power.
[0013] Another object of the present disclosure is to provide a winding technique that ensures DC contactor to consume lesser power as compared to ac controlled contactor.
[0014] Yet another object of the present disclosure is to provide a winding arrangement that allows economically efficient application of a single coil with three terminals.

SUMMARY
[0015] Aspects of the present disclosure generally relate to the field of DC controlled contactors. In particular, the present disclosure pertains to application of normally closed (NC) contacts in DC controlled contactors. More specifically, the present disclosure relates to a winding technique for DC controlled contactors that utilize a delayed NC contact.
[0016] In an aspect, the present disclosure provides a winding arrangement for DC controlled contactor that includes a dual winding configured with a pickup winding and a hold-on winding, wherein the hold-on winding can be wound on the pickup winding, wherein the pickup winding can be configured to be short such that, after the contactor is switched on, the hold-on winding and the pickup winding get connected in series. Further, the hold-on winding can be a low resistance winding and the pickup winding can be a high resistance winding.
[0017] In an aspect, short of pickup winding can take effect by a delayed NC contact, wherein depth of the NC contact can ensure that the transition from ‘NC’ to ‘NO’ occurs only after the contact close condition, wherein changeover of the delayed NC contact can take place after a certain delay that can be translated in terms of bridge travel of the controlled contactor.
[0018] In an aspect, winding of pickup winding on top of hold-on winding can allow for faster switching due to accelerated cooling, wherein direction of winding of the hold-on winding and the pickup winding can be same with the direction favoring flux addition.
[0019] In an aspect, coil of the dual wounding can be configured to be assembled on a fixed magnet that has core shaped as letter “E”.
[0020] In an embodiment, resistance of hold-on winding shall be less than pick-up winding and resistance of the pickup winding shall be much higher than hold-on winding.
[0021] 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
[0022] 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.
[0023] FIG. 1 illustrates an exemplary top view of dc controlled contactor in accordance to an embodiment of the present disclosure.
[0024] FIG. 2 illustrates an exemplary front view of electromagnet assembly in accordance to an embodiment of the present disclosure.
[0025] FIG. 3 illustrates an exemplary perspective view of a part of electromagnet assembly in accordance to an embodiment of the present disclosure.

DETAILED DESCRIPTION
[0026] 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.
[0027] 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.
[0028] 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.
[0029] Embodiments of the present disclosure generally relate to the field of DC controlled contactors. In particular, the present disclosure pertains to application of normally closed (NC) contacts in DC controlled contactors. More specifically, the present disclosure relates to a winding technique for DC controlled contactors that utilize a delayed NC contact.
[0030] As used herein, a person known in the relevant art would appreciate that a normally closed (N.C.) contact that can generally remain closed (in a conductive state) when it, or the device operating it, is in a de-energized state or relaxed state. Moreover, the present disclosure further mentions about a normally open (N.O.) contact that can be open (in a non-conductive state) when it, or the device operating it, is in a de-energized state or relaxed state.
[0031] FIG. 1 illustrates an exemplary top view 100 of dc controlled contactor in accordance to an embodiment of the present disclosure. As illustrated, the view 100 shows a terminal 102 for coil supply A1, terminal 104 for coil supply A2, add on block 106 with auxiliary contact, common terminal of the coil circuit 108, and connecting wires 110 from the auxiliary contact to the coil terminals.
[0032] In an aspect, dual winding coil of the present disclosure can function along with electromagnet to pull the armature when the contactor can be in contact open condition and keep the magnet systems in sealed condition after contact close. Here, the outer winding functions as pick up winding and inner winding as hold-on winding.
[0033] In an embodiment, resistance of the outer winding shall be less than inner winding and resistance of the inner winding shall be much higher than outer winding. This high resistance winding therefore reduces the current drastically thereby preventing overheating of the coil. The number of turns required to achieve this high resistance can be large and this can exert large sealing force on the armature. The magnet air gap can be provided so that it will allow the force to collapse successfully once the supply is switched off.
[0034] In an aspect, supply to the coil can be provided through terminals marked 102 (A1) and 104 (A2) while third terminal 108 can be present in the dual wound coil. Terminals 108 and 104 can be shorted with the help of a delayed auxiliary contact that can be placed in add-on block 106. The shorting can be done with the help of wires indicated by 110.
[0035] In an aspect, the present disclosure provides a winding arrangement for DC controlled contactor that includes a dual winding configured with a pickup winding and a hold-on winding, wherein the hold-on winding can be wound on the pickup winding, wherein the pickup winding can be configured to be short such that, after the contactor is switched on, the hold-on winding and the pickup winding get connected in series. Further, the hold-on winding can be a low resistance winding and the pickup winding can be a high resistance winding.
[0036] In an aspect, short of pickup winding can take effect by a delayed NC contact, wherein depth of the NC contact can ensure that the transition from ‘NC’ to ‘NO’ occurs only after the contact close condition, wherein changeover of the delayed NC contact can take place after a certain delay that can be translated in terms of bridge travel of the controlled contactor.
[0037] In an aspect, winding of pickup winding on top of hold-on winding can allow for faster switching due to accelerated cooling, wherein direction of winding of the hold-on winding and the pickup winding can be same with the direction favoring flux addition.
[0038] In an aspect, coil of the dual wounding can be configured to be assembled on a fixed magnet that has core shaped as letter “E”.
[0039] In an embodiment, resistance of hold-on winding can be in the range of 16 to 18 ohms and resistance of the pickup winding can be between 1.5k ohms to 1.7k ohms.
[0040] FIG. 2 illustrates an exemplary front view 200 of electromagnet assembly in accordance to an embodiment of the present disclosure. The view 200 illustrates a moving magnet assembly 202, fixed magnet assembly 204, and a wound coil assembly 206, wherein the wound coil assembly 206 can be assembled on the fixed magnet assembly 204. Notably, the circuit can be completed with the moving magnet assembly 202 that can be attached to contactor bridge.
[0041] In an aspect, as illustrated by FIG. 2, moving magnet assembly 202 can be part of the bridge-armature system of the contactor in accordance with an implementation of the present disclosure.
[0042] FIG. 3 illustrates an exemplary perspective view 300 of a part of electromagnet assembly in accordance to an embodiment of the present disclosure. As illustrated, leads can be designated as 302, 304 and 306, wherein the leads 304 and 306 can finally form coil terminals A1 and A2. Further, lead 302 can form the common terminal of the dual winding coil. This common terminal (alternatively, common lead 302) along with the terminal formed by the lead 306 can be connected by the auxiliary contact.
[0043] In an aspect, the instant figures illustrates common lead 302 can join the inner lead of pick up winding and outer lead of hold on winding. Moreover, lead 304 can indicate outer lead of the pickup winding that can be same as coil terminal A1, lead 306 can indicate inner lead of hold-on winding that can be same as coil terminal A2 while coil 308 can be former on which pickup and hold on windings can be wound.

ARRANGEMENT FOR SWITCHING CONTACTOR ON
[0044] In an aspect, as illustrated in FIG. 2, dual wound coil can be assembled on an E core fixed magnet that can, in turn, be assembled on base plate. The front housing that has a E shaped armature can then be assembled on the base plate. The inner winding of the coil can be shorted with the help of an auxiliary contact.
[0045] When the coil is energized at A1-A2 terminals, current path can be traced through the outer winding of the coil as the inner winding can be effectively shorted by the auxiliary block. The coil along with electromagnet generates force to pull the armature.
[0046] The auxiliary contact can be placed in a housing with a bridge. The auxiliary contact can be actuated by means of movement of the bridge that can be connected to the main contactor armature. When the main armature is pulled by the coil electromagnet system, the auxiliary bridge that can be linked with the main armature can also move, resulting in changeover from NC to NO. This will result in series connection of the high resistance winding with the low resistance winding thereby reducing the coil current.
[0047] In an implementation, for dual winding coil can be wound in the following method. Initially, high resistance winding is initially wound on the coil former so as to form the inner winding. The low resistance winding is then wound on top of the inner winding so as to form the outer winding. The leads of the inner and outer winding are finished in such a way that the two windings are connected in series with the direction favoring flux addition. The outer lead of the inner winding can be joined with the inner lead of the outer winding so as to form the common lead 302 as illustrated in Figure 3. After the lead is formed, the winding process of the outer wind is commenced. The inner winding is isolated from the outer winding. Therefore, this method of winding the coil results in three terminals instead of two as in the case of conventional coils.
[0048] In an aspect, for the method of coil winding, the low resistance winding can be wound above the high resistance winding. This can be beneficial to the coil functioning in many ways. The low resistance winding as the outer winding can be more exposed to the external ambient temperature compared to the inner winding. As the low resistance winding carries high current during starting, exposure to external ambient can help in faster cooling. This can facilitate faster switching operation of the contactor.
[0049] In an aspect, since switching frequency of a conventional dc controlled contactor can be very low due to its huge size, the dual winding arrangement (as mentioned hereinbefore) can allow the contactor to be switched at a frequency that can be comparable with the switching frequency of ac controlled contactors. Another alternative to this method can be to place low resistance winding initially (inner winding) and thereafter to place the high resistance winding on top of the inner winding. The benefits of faster cooling of the pickup winding can be negated in this method (reverse winding with low resistance as inner winding) as the hold-on (high resistance) winding is exposed to the external (ambient air). As the current carried by the hold-on winding is low, exposing the hold on winding to the external ambient does not pose any specific benefit.
[0050] In an aspect, as low resistance winding can be preferably wound as the outer winding, the effective mean length will increase. This can allow lower number of turns to achieve the targeted coil resistance resulting in less bulky coils compared with conventional DC coils. Due to smaller size, the heat removal from the coils can be increased, resulting in reduced losses and higher efficiency of coils. Due to the aforementioned mentioned winding arrangement of coil, AC magnet can be used in the DC circuit. Hence, the length of the dc magnet can be reduced that can lead to reduced magnetic losses.
[0051] In an aspect, depending upon requirements of the mechanism and general design for proper functioning of the contactor, the electromagnetic system can be designed such that the force exerted by it should exceed the combined forces exerted by the contact and return springs of the contactor. Also, the force exerted by the system in the contact open condition needs to be large enough to pull the armature to the fixed magnet.
[0052] Also, in order to prevent the coil from overheating due to high current, the mechanism must reduce the current carried by the coil once the contacts have reached the closed position. This condition can be achieved in the invention with the help of the delay provided by the ‘NC ‘contact of the auxiliary contact block. The delay provided by the auxiliary contact is translated in terms of travel of the bridge. Therefore, the depth of the ‘NC’ contact should be such that the transition from ‘NC’ to ‘NO’ should occur only after contact close condition.
[0053] In an aspect, in accordance with winding direction and lead finishing of the wound coil of the present disclosure, the high resistance wire can be initially wound on the former. Once the number of turns is wound, the low resistance winding can be wound above the high resistance winding, maintaining the winding direction as same. The wires can then be connected in series.
[0054] In an aspect, manufacturing of the dual winding coil can be simple as it is not much different from the conventional process of winding. Modifications can be made in the contactor for accommodation of the third terminal. Hence, the cost difference between the dc controlled contactor and conventional ac contactor can be minimal. Again, because of the insulation techniques adopted in the finishing of the wound coils, the probability of coil burning due to poor finishing can be reduced.
[0055] Thus, the present disclosure provides a winding arrangement for DC controlled contractors that reduce the requirement of large winding space and assembly costs related thereto, and increases productivity, while resulting in an overall reduction in the time and effort of its implementation.
[0056] 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
[0057] The present disclosure provides a simple, efficient and economical winding arrangement for DC controlled contractors so as to obviate aforementioned shortcomings encountered in the art.
[0058] The present disclosure provides a construction of coil of control circuit that ensures DC contactor to consume lesser power.
[0059] The present disclosure provides a winding technique that ensures DC contactor to consume lesser power as compared to ac controlled contactor.
[0060] The present disclosure provides a winding arrangement that allows economically efficient application of a single coil with three terminals.