Claims:We claim:
1. A device for machining dynamoelectric machine pole key, comprising of:
a base plate (10) secured in the machine bed through threaded means (11), (12);
a slot (32) in base plate (10) to provide slot space for laying down at least one pole key bar (30);
plurality of screw(s) (22) to provide required clamping force on sidewise laid pole key bar (30) against the aggressive machining forces when the plurality of screw(s) (22) is configured in respective plurality of hole(s) (21); and
wherein the screw(s) (22) in the hole(s) (21) of the base plate (10) are pushed against the pole key bar (30) to arrest any rattling movement during machining.
2. The device as claimed in claim 1, wherein the number of the pole key bar(s) (30) depends on the machine’s ability to meet material removal rate, finished product lead time, strength of the materials used in different components in the device.
3. The device as claimed in claim 1, wherein the minimum width of the gap in the base plate (10) is in close tolerance to the width of the pole key bar (30).
4. The device as claimed in claim 1 or 3, wherein the height of the slot (32) is at least more than 2mm to that of the height of the pole key bar (30).
5. The device as claimed in claim 1 or 4, wherein at least one the pole key bar (30) is preferably single or in the form of pole key stack.
6. The device as claimed in claim 1, wherein the machine bed is preferably T-slot shaped bed.
7. A method for machining dynamoelectric machine pole key, comprising of the steps:
securing base plate (10) in the T-slot bed of the machine by using threaded means (11), (12) uprightly;
placing the pole key bar (30) or in form of pole key stack in the slot (32) of base plate (10); and
configuring shank (14) of the screw(s) (22) in the hole(s) (21) of the base plate (10) to fasten into the plurality of hole(s) (21) in base plate (10) to provide clamping force on pole key bar (30) against the aggressive machining forces.
, Description:A DEVICE AND METHOD OF MACHINING DYNAMOELECTRIC MACHINE POLE KEY
TECHNICAL FIELD
[0001] The present disclosure, in general, relates to torque-transmitting couplings of the key-and-keyway type. More particularly, this invention relates to an improved means for obtaining great accuracy in manufacturing of dynamoelectric machine pole key means for rigidly holding/locking armature of a stationary or rotating member, such as a rotor of dynamoelectric machine.
BACKGROUND
[0002] Background description includes information that may be useful in understanding the present invention.
[0003] The dynamoelectric machine such as a brushless alternator is composed of two generators, one as the exciter and one as the main generator. The main generator's field winding is in the rotor, the armature winding is in the stator (which will emit electrical output); the exciter's armature winding is in the rotor, and the field winding is in the stator.
[0004] The working principle of the brushless alternator is to excite the excitation winding of the exciter on the stator, and the rotor armature winding will emit alternating current. After rectification, the rotor will supply power to the main generator in the excitation winding of the rotor, thereby making the main power generation. The machine senses the required AC current in the armature winding of the stator. This is the brushless working principle of a general alternator.
[0005] In large size turbo-generators, armature pole key is a component of a brushless exciter seated in exciter shaft keyway to retain the exciter armature in its position and to transmit the torque. To retain these pole key, plurality of key slots is longitudinally disposed on exciter rotor circumference. The pole key in the pole key slot should remain in tight relation with respect to armature to prevent relative motion of the armature during exciter operation wherein it rotates at 3000 rpm to generate required excitation. These pole key are significant in reducing torque ripple as well.
[0006] Technical problem: Over time and during use of the dynamoelectric machine, if these pole keys are not machined with precise dimensional accuracy, exciter armature may become loose which can cause catastrophic failure. Such looseness is obviously undesirable and it is required that these pole keys are accurately manufactured without fault or err.
[0007] The methods as per prior art includes performing different operations on pole keys on plurality of manufacturing machines which not only result in expensive time delays in multiple job and related tool settings but also in transferring the said pole key means on different machine. Also, all these machines are required to be sequentially lined up to accommodate, without delay, in their manufacturing schedule. Multiple job settings not only creates operator fatigue but also reduce the job quality for obvious reasons well known to person skilled in the art.
[0008] Despite the appreciable advances which have been made in the machining of key-type couplings, still further improvement is desired so that larger torsional loads can be transmitted safely and efficiently.
[0009] Technical Solution: Accordingly, there is a need to manufacture pole keys which are designed to prevent axial or rotary displacement of pole keys, and to eliminate the possibility of the exciter armature slipping out of the rotor during operation of the exciter machine, as a result of severe electrical and mechanical forces.
OBJECTS OF THE DISCLOSURE
[0010] Some of the objects of the present disclosure, which at least one embodiment herein satisfy, are listed hereinbelow.
[0011] It is a general object of the present disclosure is to provide a device and method for machining slender pole keys, while eliminating issues related to prior art such as poor manufacturing quality and low production efficiency.
[0012] It is another object of the present disclosure is to provide device and method for machining pole keys which provide enhanced ergonomics and reduced operator fatigue.
[0013] It is another object of the present disclosure is to provide machining pole keys which makes it possible that a number of operations performed on single means to significantly reduce setting/machining time and expensive delays in machining of pole keys means on different machining.
[0014] It is another object of the present disclosure is to provide a device that has minimum number of structurally durable parts cooperatively assembled in a compact organization and the method is simple, economical, foolproof and inherently free from tendency to err or fall out of adjustment.
[0015] These and other objects and advantages of the present invention will be apparent to those skilled in the art after a consideration of the following detailed description taken in conjunction with the accompanying drawings in which a preferred form of the present invention is illustrated.
SUMMARY
[0016] This summary is provided to introduce concepts related to a portable link reciprocating device. The concepts are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.
[0017] In an embodiment, the present disclosure relates to a device for machining dynamoelectric machine pole key, comprising of a base plate secured in the machine bed through threaded means on both the ends, a slot in base plate to provide slot space for laying down at least one pole key bar, multiple screw(s) are configured into each respective multiple hole(s) to provide required clamping force on sidewise laid pole key bar against the aggressive machining forces to arrest any rattling movement during machining. The method comprises of locking the base plate in the T-slot bed with the help of the threading means provided at both ends. The pole key bar or a stack of pole key bar is then placed in the slot provided onto the base plate and hole(s) provided equidistantly on the base plate are used to fasten the screw(s) to provide clamping force on pole key bar against the aggressive machining forces.
[0018] In an aspect, the number of the pole key bar(s) depends on the machine’s ability to meet material removal rate, finished product lead time, strength of the materials used in different components in the device.
[0019] In an aspect, the minimum width of the gap in the base plate is in close tolerance to the width of the pole key bar.
[0020] In an aspect, the the height of the slot is at least more than 2mm to that of the height of the pole key bar.
[0021] In an aspect, wherein the pole key bar is preferably single or in the form of pole key stack.
[0022] In aspect, the machine bed is preferably T-slot shaped bed.
[0023] 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.
[0024] It is to be understood that the aspects and embodiments of the disclosure described above may be used in any combination with each other. Several of the aspects and embodiments may be combined to form a further embodiment of the disclosure.
[0025] The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent by reference to the drawings and the following detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] The accompanying drawings, which are incorporated in and constitute a part of this disclosure, illustrate exemplary embodiments and, together with the description, serve to explain the disclosed principles. In the figures, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. The same numbers are used throughout the figures to reference like features and components. Some embodiments of system and/or methods in accordance with embodiments of the present subject matter are now described, by way of example only, and with reference to the accompanying figures, in which:
[0027] FIG. 1 illustrate an isometric representation of device for simultaneous processing of large size dynamoelectric machine pole key.
[0028] FIG. 2 illustrates a cross-sectional representation of device for simultaneous processing of large size dynamoelectric machine pole key.
[0029] It should be appreciated by those skilled in the art that any block diagrams herein represent conceptual views of illustrative systems embodying the principles of the present subject matter.
DETAILED DESCRIPTION
[0030] The detailed description of various exemplary embodiments of the disclosure is described herein with reference to the accompanying drawings. It should be noted that the embodiments are described herein in such details as to clearly communicate the disclosure. However, the amount of details provided herein 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 scope of the present disclosure as defined by the appended claims.
[0031] It is also to be understood that various arrangements may be devised that, although not explicitly described or shown herein, embody the principles of the present disclosure. Moreover, all statements herein reciting principles, aspects, and embodiments of the present disclosure, as well as specific examples, are intended to encompass equivalents thereof.
[0032] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments. As used herein, the singular forms “a",” “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises,” “comprising,” “includes” and/or “including,” when used herein, specify the presence of stated features, integers, steps, operations, elements and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and/or groups thereof.
[0033] It should also be noted that in some alternative implementations, the functions/acts noted may occur out of the order noted in the figures. For example, two figures shown in succession may, in fact, be executed concurrently or may sometimes be executed in the reverse order, depending upon the functionality/acts involved.
[0034] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which example embodiments belong. It will be further understood that terms, e.g., those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
[0035] The present invention relates to a device and method of machining dynamoelectric machine pole key with precise dimensional accuracy. The device in the present invention comprises of a base plate 10 that is fixed on the machine belt with the help of threading means 11, 12. The threading means 11, 12 is a big sized nut and bolt fastened at the ends of the base plate 10. The pole key bar or plurality of pole key bars 30 are laid onto a slot 32 provided on the base plate 10. The base plate 10 has screw(s) for providing clamping force in the sidewise laid pole key bar 30 against the aggressive machining forces when the screw(s) 22 is configured in hole 21 to stop the rattling movement of the pole key bar(s) 30 during machining.
[0036] The method for machining dynamoelectric machine pole key comprises the steps of locking the base plate 10 in the T-slot bed with the help of the threading means 11, 12 provided at both ends. The pole key bar(s) or a stack of pole key bar 30 is then placed in the slot 32 provided onto the base plate 10. The hole(s) 21 provided on the base plate 10 are used to fasten the screw(s) 22 with the help of a shank 14 to provide clamping force on pole key bar 30 against the aggressive machining forces.
[0037] Referring to figure 1 and 2, the base plate 10 of the device is secured in the T-slot bed of the machine uprightly using a threaded means 11, 12. The threaded means or bolt 11 is threaded at suitable lengths at its shank 14 so as to first secure the base plate 10.
[0038] Once the base plate 10 is secured in machine bed using threaded means 11, 12, the pole key bar 30 as single job or plurality of bars adjacent to each other. The bar 30 is laid parallel in slot 32 of base plate 10. The number of the pole key bar(s) 30 depends on the machine’s ability to meet material removal rate, finished product lead time, strength of the materials used in different components in device.
[0039] However, the width of the slot 32 can be varied depending upon the number of pole key bars 30 to be simultaneously machined in single setting and the machining abilities of the machine tool. Also the width of the slot 32 in plate 10 is in close tolerance to the width of at least one bar 30 and the width of the gap 32 can be increased in multiples of the width of bar 30.
[0040] Once the pole key bar 30 is placed on the base plate 10, the slot 32 and the shank 14 of the screw 22 passes through the hole 21 of the base plate 10 to provide required job clamping force on pole key bar 30 against the aggressive machining forces to arrest any rattling movement during machining.
[0041] The number of pole key bar 30 in a stack depends on the machine’s ability to machine the stack in one go while meeting the quality standards. This may be material removal rate, finished product lead time, strength of the material used in the device.
[0042] Also, to enhance threading strength, it is advisable that the height of slot 32 should at least be more that 2mm to that of the height of a single bar 30 and the minimum width of the gap in the base plate 10 is in close tolerance to the width of the pole key bar 30.
[0043] With the present device and method for machining dynamoelectric machine pole key, the following technical advantages are obtained.
[0044] The possibility of the exciter armature slipping out of the rotor during operation of the exciter machine, as a result of severe electrical and mechanical forces is eliminated.
[0045] Due to the simplicity in its construction and operation, the desired quality of machining of said slot tightening means can be reproduced.
[0046] The larger torsional loads can be transmitted safely and efficiently.
[0047] 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.