1、NEMA Standards PublicationNational Electrical Manufacturers AssociationNEMA CB 1-2000 (R2012)Brushes for Electrical MachinesCB 1-1995 Page 1-ii NEMA Standards Publication CB 1-2000 (R2012) Brushes for Electrical Machines Published by: National Electrical Manufacturers Association 1300 N. 17th Street
2、, Suite 1752 Rosslyn, Virginia 22209 Copyright 2012 by the National Electrical Manufacturers Association. All rights including translation into other languages, reserved under the Universal Copyright Convention, the Berne Convention for the Protection of Literary and Artistic Works, and the Internat
3、ional and Pan American Copyright Conventions. CB 1-2000 (R2012) Page ii NOTICE AND DISCLAIMER The information in this publication was considered technically sound by the consensus of persons engaged in the development and approval of the document at the time it was developed. Consensus does not nece
4、ssarily mean that there is unanimous agreement among every person participating in the development of this document. The National Electrical Manufacturers Association (NEMA) standards and guideline publications, of which the document contained herein is one, are developed through a voluntary consens
5、us standards development process. This process brings together volunteers and/or seeks out the views of persons who have an interest in the topic covered by this publication. While NEMA administers the process and establishes rules to promote fairness in the development of consensus, it does not wri
6、te the document and it does not independently test, evaluate, or verify the accuracy or completeness of any information or the soundness of any judgments contained in its standards and guideline publications. NEMA disclaims liability for any personal injury, property, or other damages of any nature
7、whatsoever, whether special, indirect, consequential, or compensatory, directly or indirectly resulting from the publication, use of, application, or reliance on this document. NEMA disclaims and makes no guaranty or warranty, expressed or implied, as to the accuracy or completeness of any informati
8、on published herein, and disclaims and makes no warranty that the information in this document will fulfill any of your particular purposes or needs. NEMA does not undertake to guarantee the performance of any individual manufacturer or sellers products or services by virtue of this standard or guid
9、e. In publishing and making this document available, NEMA is not undertaking to render professional or other services for or on behalf of any person or entity, nor is NEMA undertaking to perform any duty owed by any person or entity to someone else. Anyone using this document should rely on his or h
10、er own independent judgment or, as appropriate, seek the advice of a competent professional in determining the exercise of reasonable care in any given circumstances. Information and other standards on the topic covered by this publication may be available from other sources, which the user may wish
11、 to consult for additional views or information not covered by this publication. NEMA has no power, nor does it undertake to police or enforce compliance with the contents of this document. NEMA does not certify, test, or inspect products, designs, or installations for safety or health purposes. Any
12、 certification or other statement of compliance with any health or safetyrelated information in this document shall not be attributable to NEMA and is solely the responsibility of the certifier or maker of the statement. CB 1-2000 (R2012) Page iii Copyright 2012 by the National Electrical Manufactur
13、ers Association FOREWORD NEMA CB 1-2000, Brushes for Electrical Machines, revises and supersedes the previous edition, CB 1-1995. It represents the general practice in the design and manufacture of brushes by the electrical manufacturing industry and is issued to provide practical information and to
14、 assist the user in the proper selection of such brushes. The standards in this publication are the result of many years of research and investigation and have been developed through continual consultation among manufacturers, users, and national engineering societies. When utilized by the industry,
15、 they have resulted in improved quality of electrical products and economy in manufacture. These standards are subject to periodic review. They have been revised from time to time to meet changing economic conditions and technical progress. In keeping with the policy of the U.S. National Committee o
16、f the International Electrotechnical Commission (IEC), an effort has been made to bring this publication into conformity with existing IEC publications to the extent practical. This revision incorporates provisions of the IEC publications where practical and where they can be achieved without hardsh
17、ip to the user and the industry. This standards publication is, therefore, not in complete conformity with IEC standards. With reference to dimensional data, it should be noted that the bracketed values represent conversion of SI units and are not necessarily IEC specified values. To avoid confusion
18、 to the user, brushes manufactured in conformity with IEC tolerances should be so identified. In the preparation of this standards publication the input of users and other parties of interest has been solicited through American National Standards Committee C64. Inquiries, comments, and proposed or r
19、ecommended revisions should be submitted to the concerned NEMA product subdivision by contacting the: Vice President, Engineering Department National Electrical Manufacturers Association 1300 N. 17th Street Rosslyn, Virginia 22209 The Carbon/Manufactured Graphite Section developed this standards pub
20、lication. Section approval does not necessarily imply that all section members voted for its approval or participated in its development. At the time it was approved, the group/section was composed of the following members: Carbone-Lorraine North America Corporation Parsippany, NJ Fulmer Company Inc
21、orporated Westmoreland, PA Graphite Metallizing Corporation Yonkers, NY Helwig Carbon Products, Incorporated Milwaukee, WI Hoffmann Carbon, Incorporated Bradford, PA Kirkwood Industries Cleveland, OH Morgan Advanced Materials position 10, the right side; position 11, the front; position 12, the left
22、 side; and position 13, the back. To determine the correct designation of locations, the following procedure is used: a. If the brush has a beveled top or bottom, or both (commutator type), observe with front side toward you in accordance with Figures 1-41 and 1-43. b. If the brush has a greater thi
23、ckness (tangential dimension) than width (axial dimension) (slip-ring type), observe in accordance with Figures 1-42 and 1-43. Hold with the front side toward you if beveled. c. If the brush is tapered or wedge-shaped (wedge commutator type), observe with the thinner side to the left in accordance w
24、ith Figure 1-44. d. If the brush has no top or bottom bevel and has a top clip, the side of the brush attached to the clip is considered as the back if the width (axial dimension) is greater than the thickness (tangential dimension); otherwise, it is considered as the right side. Figure 1-41 Figure
25、1-42 COMMUTATOR TYPE SLIP-RING TYPE CB 1-2000 (R2012) Page 15 Copyright 2012 by the National Electrical Manufacturers Association Figure 1-43 SPECIAL CASES Figure 1-44 WEDGE COMMUTATOR TYPECB 1-2000 (R2012) Page 16 Copyright 2012 by the National Electrical Manufacturers Association 1.8.3 Shunt Lengt
26、h The shunt length (L) is the distance from the extreme top of the brush material to the center of the hole or slot in the terminal, or the center of the inserted portion of a plug terminal or, if there is no terminal, to the end of the shunt. To determine the length of the shunt, extend the cable s
27、traight from the top end in a line parallel with the axis of the brush. See Figures 1-45 and 1-46. L LL LFigure 1-45 Figure 1-46 SHUNT LENGTH (NO TERMINAL) SHUNT LENGTH (WITH TERMINAL) 1.9 BRUSH CLIPS Brush clips, referred to as “clips“ in this publication, are parts attached to the brush which serv
28、e to accommodate the spring, spring finger, or hammer, or to act as guides. Where these serve to prevent the wear of the carbon due to the pressure finger, they are called “hammer“ or “finger“ clips. Some clips serve the purpose of lifting the brushes or providing a stop. The width of the clips is d
29、esignated by K. 1.9.1 Hammer Clips 1.9.1.1 A Type A clip consists of a strip formed to lie on the top of the brush and attached to the side of the brush. See Figure 1-47. 1.9.1.2 A Type A extra wide clip is similar to the Type A clip, except that it covers nearly the whole top of the brush. See Figu
30、re 1-48. CB 1-2000 (R2012) Page 17 Copyright 2012 by the National Electrical Manufacturers Association KKFigure 1-47 Figure 1-48 TYPE A TYPE A EXTRA-WIDE 1.9.1.3 An Offset A clip is similar to the Type A extra wide clip, except that the rivet is not placed at the centerline of the brush. See Figure
31、1-49. Figure 1-49 OFFSET A 1.9.1.4 An Extended A (Cantilever) clip is similar to the Type A clip but extends beyond the side of the brush to accommodate the brush pressure finger. Dimension “e“ is measured in the plane shown in Figure 1-50 and is taken to a straight edge. Minimum thickness of clip m
32、aterial is .03 inches (0.71 mm). See ASTM A480, A568 or B2483 for tolerances for thickness of the type of material used. An alternate method to dimension the A clip or protrusion shown in Figure 1-50 is to provide dimension U (see Figure 1-63). These methods may be applied to extended P measurements
33、 (also see Figure 1-63). 3 Available from the American Society for Testing and Materials, 1916 Race Street, Philadelphia, PA 19103. The titles are as follows: A480-80 General Requirements for Delivery of Flat-Rolled Stainless and Heat-Resisting Steel Plate, Sheet, and Strip A568-74 General Requireme
34、nts for Steel, Carbon and High-Strength Low-Alloy Hot-Rolled Sheet, Hot-Rolled Strip, and Cold- Rolled Sheet B248-11 General Requirements for Wrought Copper and Copper-Alloy Plate, Sheet, Strip, and Rolled Bar CB 1-2000 (R2012) Page 18 Copyright 2012 by the National Electrical Manufacturers Associat
35、ion Figure 1-50 EXTENDED A (CANTILEVER) A 1.9.1.5 An Angular A clip is similar to the Type A clip but is attached to an angle to accomplish the same purpose as beveling the holder end of the brush. See Figure 1-51. 1.9.1.6 A Channel A clip is similar to the Type A clip, except that it has the edges
36、turned up as a guide to position the spring finger on top of the brush. See Figure 1-52. KKFigure 1-51 Figure 1-52 ANGULAR A CHANNEL A 1.9.2 Lifting and Guide Clips 1.9.2.1 Type B is a lifting clip having two lugs, in one of which there is a hole and in the other a slot opening toward the side of th
37、e brush. The slot opening direction is optional, depending on the application. See Figure 1-53. 1.9.2.2 Type C is a guide clip. It is generally fastened into a groove in the brush by one or more rivets. See Figure 1-54. CB 1-2000 (R2012) Page 19 Copyright 2012 by the National Electrical Manufacturer
38、s Association KKFigure 1-53 Figure 1-54 TYPE B TYPE C 1.9.2.3 Type D is a bail-type lifting clip. The bail is fixed to the brush by a metal plate. See Figure 1-55. 1.9.2.4 Type E is a lifting clip formed into the shape of a hook. See Figure 1-56. Figure 1-55 Figure 1-56 TYPE D TYPE E 1.9.2.5 Type F
39、is a lifting clip similar to the Extended A (Cantilever type) hammer clip and is usually made in double thickness or two pieces. See Figure 1-57. The clip protrusion is dimensioned perpendicularly from the brush surface to the end of the clip. An alternate method to dimension the A clip or protrusio
40、n is to provide dimension U as shown in Figure 1-63. KCB 1-2000 (R2012) Page 20 Copyright 2012 by the National Electrical Manufacturers Association 1.9.2.6 Type G is a lifting clip having a raised portion which projects outward from the side of the brush. See Figure 1-58. 1.9.2.7 Type H is a lifting
41、 clip similar to the Type E (hook type) clip, except that it has a minor projection which extends outward from the side of the brush. See Figure 1-59. 1.9.2.8 Type K is a lifting clip combining the features of a Type E lifting clip and an Angular A hammer clip. See Figure 1-60. KK Figure 1-57 Figure
42、 1-58 TYPE F TYPE G KKFigure 1-59 Figure 1-60 TYPE H TYPE K 1.10 BRUSH PADS Brush pads, referred to as “pads“ (are designated by “P“) in this publication, are resilient parts attached to the brush top to absorb vibration. Pads are composed of a resilient material or a combination of resilient and no
43、nresilient materials. Pads are typed according to the shape of their top surface. All of these types are of the channel design which acts as a guide to position the spring or spring finger on top of the brush. See Figure 1-61 for an example of a typical channel design. The width of the pad is design
44、ated by “K.“ 1.10.1 Type P is a pad with a plain rectangular surface. See Figure 1-62. CB 1-2000 (R2012) Page 21 Copyright 2012 by the National Electrical Manufacturers Association Figure 1-61 Figure 1-62 CHANNEL DESIGN PAD TYPE P 1.10.2 An Extended P pad protrusion is similar to a type P pad but ex
45、tends beyond the side of the brush to accommodate the brush pressure spring or finger. See Figure 1-63. Depending on the materials selected, the pad extension is critical. An alternate method to dimension the P pad is to provide dimension U as shown in Figure 1-63. Figure 1-63 EXTENDED P 1.10.3 A co
46、nvex P pad is similar to a Type P pad, except that it has a convex top. See Figure 1-64. Radius R dimension is specified. 1.10.4 A Concave P pad is similar to a Type P pad, but it has a concave top. See Figure 1-65. Radius R is specified. 1.10.5 A Single-Angle P pad is similar to a type P pad, excep
47、t it has an angled top. See Figure 1-66. 1.10.6 A Double-Angle P pad is similar to a Type P pad, but the top consists of two intersecting planes. See Figure 1-67KKCB 1-2000 (R2012) Page 22 Copyright 2012 by the National Electrical Manufacturers Association 1.11 WEAR INDICATORS Wear indicators are us
48、ed to help determine when to replace a brush or brushes. Wear indicators include slots or painted lines on the brush body, a sensor inserted in the body of the brush, or an indicating band on the shunt. KRKRFigure 1-64 Figure 1-65 CONVEX P CONCAVE P KKFigure 1-66 Figure 1-67 SINGLE-ANGLE P DOUBLE-AN
49、GLE P CB 1-2000 (R2012) Page 23 Copyright 2012 by the National Electrical Manufacturers Association Section 2 DIMENSIONS AND TOLERANCES The dimensions and tolerances in this section apply only to fractional-horsepower and industrial-size brushes as classified in 1.4.2 and 1.4.3. 2.1 BRUSH DIMENSIONS 2.1.1 The dimension (D) of a brush is the dimension of the round portion and is at right angles to the length. See Figure 2-1. 2.1.2 Th
