1、- - MIL-HDBK-802 - 17 W 9999970 0058338 L W 2 Julv 1990 SUPERSEDING February 1957 NAVSEA 0981-LP-052-8140 MILITARY HANDBOOK DESIGN OF ELECTRICAL EQUIPMENT WITH SMALL STRAY MAGNETIC FIELDS (METRIC) AMSC N/A DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. A Licensed b
2、y Information Handling ServicesMIL-HDBK-02 19 M 7777770 0058337 3 MIL-HDBK-802(SH) 2 July 1990 FOREWORD 1. This military handbook is approved for use by the Naval Sea Systems Command, Department of the Navy, and is available for use by all Departments and Agencies of the Department of Defense, 2. Be
3、neficial comments (recommendations, additions, deletions) and any pertinent data which may be of use in improving this document should be addressed to: Commander, Naval Sea Systems Command, SEA 5523, Department of the Navy, Washington, DC 20362-5101 by using the self-addressed Standardization Docume
4、nt Improvement Proposal (DD Form 1426) appearing at the end of this document or by letter. ii Licensed by Information Handling Services MIL-HDBK-802 17 7979970 00583qO T W . MIL-HDBK-802(SH) 2 July 1990 CONTENTS Page 1.2 fl I L . 3 . 3.1 3.2 3.2.1 3.3 3.3.1 3.3.2 3.3.2.1 3.3.2.2 3.3.2.3 3.3.2.4 3.3.
5、2.5 3.3.3 3.3.3.1 3.3.3.1.1 3.3.4 3.3.5 3.3.6 3.4 3.4.1 3 i4.1.1 3.4.1.1.1 3.4.1.2 3.4.1.2.1 3.4.1.2.2 3.4.1.3 3.4.1.3.1 3.4.1.3.2 SCOPE . General Application APPLICABLE DOCUMENTS (not applicable) . GENERAL DESIGN CONSIDERATIONS . Introduction . Definition of a stray magnetic field . Measuring stray
6、 magnetic field . Design for smallest stray magnetic field . General The effect of a ferromagnetic material on a magnetic field The magnetic field of a ferromagnetic material The effects of ferromagnetic materials on the magnetic field of a conductor . The effect of ferromagnetic material on a solen
7、oid Avoid enclosure of magnetic material in current loops . Magnetic material between two current loops of opposite polarity Shielding Shielding effectiveness Using relative permeability to approximate shielding effectiveness . Calculating stray magnetic field . Theory of design for small stray magn
8、etic field Organization of handbook . Illustration and measurement of stray magnetic field The effect of conductor shapes on stray magnetic fields . Introduction . Right-hand rule Straight wire Infinitely long straight wire Finite length straight wire Loops Square loop Circular loop 1 1 1 1 2 2 2 3
9、4 5 5 6 6 7 7 7 8 8 8 8 8 8 9 10 10 11 . iii Licensed by Information Handling ServicesParagraph 3.4.1.4 3.4.1.5 3.4.1.5.1 3.4.1.5.2 3.5 3.6 3.7 3.8 4 . 4.1 4.1.1 4.1.1.1 4.1.2 4.1.2.1 4.1.2.2 4.1.2.3 4.1.3 4.1.4 4.1.5 4.2 4.2.1 4.2.1.1 4.2.1.1.1 4.2.1.2 4.2.1.2.1 4.2.1.2.2 4.2.1.2.2.1 4.2.1.2.2.2 4,
10、2.1.2.3 4.2.1.2.3.1 4.2.1.2.4 4.2.1.2.5 4.2.1,2.5,1 4.2.1.3 4.2.1.4 4.2.1.4.1 CONTENTS . Continued Page MIL-HDBK-80Z 37 m 7777770 0058343 3 m MLL-HDBK-a02(SH) 2 July 1990 Summary . Examples A simple experiment . A large-scale experiment How a magnetic mine works . How a magnetic mine can be defeated
11、 . How a ship magnetic field can be made equal to zero Practical ways of minimizing ship magnetic fields 12 12 12 13 14 14 14 14 MAGNETIC FIELDS PRODUCED BY CURRENT LOOPS General information . Current loop Coil Small and large current loops . Example using small and large loop formulas . Comparison
12、of small and large loop formulas . Small loop formulas . Coordinate axes . Conventions on sign . Notation Magnetic field produced by single current loop . Small current loops . Small current loops and magnetic dipoles Representations of current loops Computation of magnetic dipole moment . Current l
13、oops of equal area . Current loops of differing areas Example . Magnetic moment of loops of differing Vector character of magnetic moment . Vertical component Magnetic moment of an inclined current loop . Magnetic fields of noncoplanar current loops Splitting current loops into smaller loops Magneti
14、c field contours . Magnetic field of a dipole Magnetic field of an X dipole . areas 15 15 15 15 15 15 16 17 17 17 ia ia ia ia 19 19 19 19 20 20 20 21 21 21 22 22 23 23 iv Licensed by Information Handling ServicesParagraph 4.2.1.4.1.1 4.2.1.4.1.2 4.2 1.4.1.3 4.2.1.4.1.4 4.2.1.4.2 4.2.1.4.2.1 4.2.1.4.
15、2.2 4.2.1.4.2.3 4.2.1.4.3 4.2.1.4.3.1 4.2.1.4.3.2 MIL-HDBK-802(SH) 2 July 1990 CONTENTS - Continued Page The x component of the magnetic field of an X dipole 24 The y component of the magnetic field of an X dpoie 25 The z component of the magnetic field of an X dipole 26 Total magnetic field produce
16、d by an X dipole . 26 The magnetic field produced by a Y dipole . 26 The x component of the magnetic field of The y component of the magnetic field of The z component of the magnetic field of The magnetic field produced by a 2 dipole . 28 The x component of the magnetic field of a Z dipole . 28 The
17、y component of the magnetic field of a Z dipole . 28 The z component of the magnetic field of a Z dipole . 29 Large current loops . 29 General 29 Horizontal rectangular loop . 29 Narrow horizontal rectangular loop 31 Vertical rectangular loop . 32 Magnetic field produced by two or more a Y dipole .
18、27 a Y dipole . 27 a Y dipole . 27 . Narrow vertical rectangular loop 33 small current loops 34 General . 34 Principle of superposition 34 Simple example of superposition . 34 Principle of compensation . 35 Compensation with two current loops . 35 Compensation with more than two current loops Exampl
19、e of compensation Validity Vector character of compensation General information on formulas . Convenience . Accuracy Formulas for dipole arrays Contour maps of dipole arrays . Two dipole arrays . 35 36 36 37 37 38 38 38 38 38 Licensed by Information Handling ServicesMIL-HDBK-802 19 7977770 0058343 5
20、 MIL-HDBK-802(SH) 2 July 1990 CONTENTS . Continued Paragraph 4.3.2.5.2 4.3.2.5.3 4.3.2.6 4.3.2.7 4.3.2.8 4.3.3 4.3.3.1 4.3.3.1.1 4.3.3.2 4.3.3.3 4.3.3.4 4.3.3.5 4.3.3.6 4.3.3.7 4.3.3.8 4.3.3.9 4.3.3.10 4.3,3.11 4.3.3.12 4.3.3 13 4.3.3.14 4.3.3.15 4.3.3.16 4.3.3,17 4.3.3.18 4.3.3.18,l 4.3,3.19 4.3.3
21、e 20 4.3.3.21 4.3.3 * 22 4.3.3.23 4.3.3.24 4.3.3.25 4.3.3.26 4.3.4 4.3.4.1 4.3.4.2 4.3.4.3 4.3.4.4 Arrays with more than two dipoles . Computation of contour maps . Dimensions Radial dipole arrays Dipole configurations . Two X dipoles on the x axis . Example of the use of parallel dipole Two X dipol
22、es on the y axis . Two X dipoles on the z axis . Two Z dipoles on the x axis . Y dipoles . configuration equations Two Z dipoles on the z axis Four X dipoles on the x axis Four X dipoles on the x axis - case 2 Four X dipoles on the y axis Four X dipoles on the z axis Four X dipoles on the xy plane F
23、our X dipoles on the xz plane Four Z dipoles on the z axis - case 1 Four Z dipoles on the z axis - case 2 . - case 1 . . Four X dipoles on the yz plane Four Z dipoles on the x axis . . Four Z dipoles on the xy plane Four Z dipoles on the yz plane Four radial dipoles on the xz plane - case 1 . Exampl
24、e of the use of radial dipole configuration equations Four radial dipoles on the xz plane case 2 . Six radial dipoles on the xz plane case 1 . Six radial dipoles on the xz plane case 2 . Eight radial dipoles on the xz plane - case 1 . Eight radial dipoles on the xz plane . case 2 . Four radial dipol
25、es on the xy plane . Eight radial dipoles on the xy plane Circular arrays in the xz plane . Advantages Vertical axis machines - . - Six radial dipoles on the xy plane Summary of formulas for circular arrays Circular arrays in the xy plane . . Page 38 39 39 39 39 40 40 41 42 43 44 45 46 47 48 49 50 5
26、1 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 68 68 68 68 vi Licensed by Information Handling Services7 . MIL-HDBK-02 17 H 7797770 0058344 7 MIL-HDBK-802(SH) 2 July 1990 Paragraph 4.3.5 4.3.5.1 4.3.5.2 4.3.6 43.7 5 . 5.1 5.2 5.3 5.3.1 5.3.2 5.3.3 5.4 5.5 5.5.1 5.5.2 5.6 5.6.1 5.6.1.1 5.6.1.1.
27、1 5.6.1.1.2 5.7 5.7.1 5.7.2 5.8 5.8.1 5.9 5.9.1 5.10 5.10.1 5.11 5.11.1 CONTENTS . Continued Page Different arrays of dipoles producing the same vertical magnetic field . Other arrays with similar equations . Compensation using arrays of dipoles producing the same vertical magnetic field Calculation
28、 of magnetic field using Taylors series expansion Location and magnitude of maximum . 69 69 70 70 70 PRINCIPLES OF DESIGNING EQUIPMENT AND CIRCUITS FOR MINIMUM STRAY MAGNETIC FIELD . General . Principles of design for small stray magnetic field . The principle of simplicity . Extreme example . Examp
29、le of extreme simplicity . Example of simplicity in field poles of generators and motors . Principles of minimum magnetic moment and minimum separation . Principle of zero net magnetic moment . Application to equipment Limitation of the principle . Principles of series and parallel compensation . Co
30、mparison of series and parallel compensation . Inequality of current division Series compensation . Parallel compensation . Use of parallel compensation Symmetry Precaution to minimize the effects of unequal current division . Principle of self compensation Orientation . Principle of mutual compensa
31、tion Principle of compatibility Justification . Principle of minimum disturbance by magnetic material Minimization of magnetic material . Utility . 71 71 72 72 72 73 73 74 74 74 75 75 75 75 75 77 77 77 77 78 78 78 78 79 79 79 79 Licensed by Information Handling ServicesMIL-HDBK-802 19 9999970 005834
32、5 9 MIL-HDBK-802(SH) 2 July 1990 CONTENTS - Continued Paragraph 5.11.2 5.12 5.12.1 5.12.2 5.13 6. 6.1 6.1.1 6.2 6.2.1 6.2.1.1 6.2.1.2 6.2.2 6.2.2.1 6.2.2.1.1 6.2.2.1.2 6.2.2.1.3 6.2.2.1.4 6.2.2.1.5 6.2.2.2 6.2.2.2.1 6.2.2.2.2 6.2.3 6.2.3.1 6.2.3.2 6.2.3.3 6.2.3.4 6.2.4 6.2.5 . 6.3 6.3.1 6.3.2 . 6.3.
33、3 6.3.4 6.3.4.1 6.3.4.2 Arrangement of conductors with respect to magnetic material . Principle of final check Need for final check Nature of the check . Objectives of design DESIGN OF MAGNETIC MINESWEEPING EQUIPMENT General . Interfacing equipment . Cable runs Cable runs modeled by current loops .
34、Single current loop . Multiple current loops Power cables and cable configurations . Dc power cables . Use of single-conductor cables Use of double-conductor cables Arrangement of cables for opposing current loops Equal current division-among cables connected in parallel Unequal current division in
35、double- conductor cables . Ac power cables . Phase conductors in a common cable Phase conductors in separate cables . Spiraling the cable run to minimize the effects of unequal current division Spiraling a four cable quad arrangement . Spiraling eight cables in a circular array Spiraling eight cable
36、s in a rectangular array Other numbers of cables . Cable spacing Concentric cable Connections between equipment and cable runs . Compatibility of cable runs and terminal Arrangement of terminals and approach by cable run Cable runs Three-terminal arrangements . Four-cable connection with endways app
37、roach to edgewise terminals . Four-cable connection with crossways approach to edgewise terminals . viii Licensed by Information Handling ServicesParagraph 6.3.4.3 6.3.4.4 6.3.4.5 6.3.4.6 6.3.4.7 6.4 6.4.1 6.4.2 6.4.2.1 6.4.2.2 6.4.3 6.4.4 6.4.5 6.4.6 6.4.6.1 MIL-HDBK-802(SH) 2 Julv 1990 CONTENTS .
38、Continued Paae Four-cable connection with endways Four-cable connection with crossways Four-cable connection with sideways Eight-cable connection Disconnect switch boxes and contactor panels . Basic conductor arrangement . Conductor bends . Conductors lying in different planes on each side of the be
39、nd Conductors lying in the same plane on each side of the bend Parallel compensation . Current loops in power circuits . Terminals . Shunt box . Description of connection . -s . Cancellation of magnetic field Straight-through disconnect switch box Folded arrangement Folded arrangement for disconnect
40、 switch box Description of connection . Advantages Equal current loops . Unequal current loops . Single-pole contactor . Flexibility of folded arrangement . The crisscross arrangement The crisscross Current loops . Difference between folded and crisscross approach to flat terminals . approach to fla
41、t terminals . approach to edgewise or flat terminals General connection method for six cables . Folded arrangement for contactor panel 6.4.6.2 Current 100 . 6.4.6.3 6.4.7 6.4.8 6.4.8.1 6.4.8.1.1 6.4.8.1.2 6.4.8.1.3 6.4.8.1.4 6.4.8.2 6.4.8.2.1 6.4.9 6.4.10 6.4.10.1 6.4.10.2 6.4.11 arrangements . 6.4.
42、12 CornDarison of folded and crisscross arrangements . Comparison or equal current division between outer conductors . Comparison for unequal current division between outer conductors . Comparision for zero current in one outer conductor and 1. O00 amperes in the other outer conductor 6.4.12.1 6.4.1
43、2 2 6:4,12.3 I . iX 95 96 97 97 99 101 101 102 102 103 103 103 103 104 104 104 106 106 107 107 107 108 108 108 108 110 110 110 111 111 111 113 113 114 114 Licensed by Information Handling Services1 MIL-HDBK-802 17 7979970 0058347 2 Paragraph 6.4.12.4 6.5 6.5.1 6.5.1.1 6.5.1.2 6.5.2 6.5.2.1 6.5.2.2 7
44、. 7.1 7.1.1 7.1.1.1 7.1.1.2 7.1.2 7.1.3 7.1.3.1 7.1.3.2 7.1.3.3 7.1.3.4 7.1.3.5 7.1.3.6 7.1.3.7 7.1.3.8 7.1.4 7.1.4.1 7.1.4.2 7.1.4.3 7.1.4.4 7.2 7.2.1 7.2.2 7.2.3 7.2.3.1 7.2.3.2 7.2.3.3 7.2.3.4 7.2.3.5 7.2.3.6 7.2.3.7 MIL-HDBK-802(SH) 2 July 1990 CONTENTS - Continued Page Conclusions 114 Design of
45、 induction clutches 115 115 Operation 117 Disadvantages 117 Induction clutch for small stray magnetic field 117 Field coils 118 119 . Typical induction clutch . . . Advantages of the form . DESIGN OF MINESWEEPING GENERATORS 119 General 119 Introduction 119 Design objectives . 119 minesweeping genera
46、tors 119 Cause of stray magnetic field 120 Essential features in generator design 120 Frame 120 Number of field poles 120 Symmetry and uniformity 120 Wiring around the frame 120 Lap-wound armature 121 Brush collector rings 121 Connections for brush collector rings . 121 Double-armature machines 121
47、121 Desirable features in generator design Angular position of takeoff points 122 Number of commutator bars 122 Brush rigging 122 Position of brush collector rings . 122 Field circuit design 122 Applicability 122 Sources of stray magnetic field produced by the field coils 122 . Application to machin
48、es other than . . . . . . . . . . 122 Minimization of stray magnetic field Number and orientation of field coils . 123 Effect of radius 124 Effect of iron 125 Uniformity and symmetry 125 Minimum number of poles in minesweeping generators 127 Minimum number of poles in other generators and in aotors
49、127 Minimization of stray magnetic field produced by the connections to the field coils 128 . . . X Licensed by Information Handling ServicesCONTENTS . Continued Pape 7.3.1 7.3.2 7.3.2.1 7.3.2.2 7.3.2.3 7.3.2.4 7.3.2.5 7.3.2.6 7.3.2.7 7.3.2.8 7.3.2.9 7.3.2.10 7.3.2.11 7.3.2.12 7.3.2.13 7.3.2.14 7.3.2.15 7.3.2.16 7.3.2.17 7.3.2.18 7.3.2.19 7.3.2.20 7.3.2.21 7.3.2.22 7.3.2.23 7.3.2.24 7.3.2.25 7.3.2.26 7.3.2.27 7.3.2.28 7.3.2.29 7.3 2.30 7.3.2.31 7.3.3 7.3.3.1 7.3.3.2 7.3.3.3 7.3.3.4 Armature circuit General . The armature circuit from the armature winding to t
