Elsevier S & T

Tribology in Electrical Environments

Prashad, H.

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Table of contents

Cover
Contentsv
Prefacexv
About the Authorxvii
Chapter 1. ANALYSIS OF BEARINGS AND LUBRICANTS IN ELECTRICAL ENVIRONMENTS: A STATE-OF-THE-ART REVIEW1
1.1 Introduction1
1.2 Rolling-Element Bearings3
1.3 Lubricants6
1.4 Hydrodynamic Journal Bearings7
1.5 Hydrodynamic Thrust Bearings8
1.6 Conclusions9
References10
Chapter 2. SHAFT VOLTAGES AND THEIR ORIGIN IN ROTATING MACHINES AND FLOW OF ELECTRIC CURRENT THROUGH15
2.1 Introduction15
2.2 Causes for the Origin of Shaft Voltages15
2.3 Factors Affecting the Shaft Voltages21
2.4 Reasons for Epidemic Shaft Current Problems21
2.5 Passage of Current Through Bearings22
2.6 Bearing Electrical Parameters22
2.7 Conclusions23
Chapter 3. BEHAVIOR OF LUBRICANTS IN ROLLING-ELEMENT BEARINGS UNDER THE INFLUENCE OF ELECTRIC CURREN25
3.1 Introduction25
3.2 The Experimental Facilities27
3.3 The Experimental Procedure31
3.4 Discussion on the Results55
3.5 Conclusions66
References67
Chapter 4. THRESHOLD VOLTAGE PHENOMENON AND EFFECT OF OPERATING PARAMETERS ON THE THRESHOLD VOLTAGE71
4.1 Bearing Threshold Voltage71
4.2 Test Set-Up and Investigations72
4.3 Theoretical75
4.4 Influence of the Operating Parameters and Lubricant Characteristics on Threshold Voltages78
4.5 Phenomenon of Bearing Impedance80
4.6 Influence of the Operating Parameters and Minimum Film Thickness on Bearing Impedance82
4.7 Different Types of Bearing Failure84
4.8 Conclusions85
References86
Chapter 5. EFFECT OF ELECTRIC CURRENT ON THE TRACK SURFACES OF ROLLING-ELEMENT BEARINGS89
5.1 A General Review89
5.2 Process of Formation of Corrugations91
5.3 Theoretical Determination of Pitch and Width of Corrugations on Roller Track of Races and Roller91
5.4 Theoretical Determination of Pitch and Width of Corrugations on Ball Track of Races and Balls of94
5.5 Experimental Investigations99
5.6 Effect of Various factors on Corrugations and on Bearing Surfaces103
5.7 Discussion on Various Aspects of Corrugations109
5.8 Conclusions111
References112
Chapter 6. ELECTRICAL PARAMETERS OF ROLLING-ELEMENT BEARINGS115
6.1 Introduction115
6.2 Electrical Parameters of Roller Bearings116
6.3 Electrical Parameters of Ball Bearings124
6.4 Data Under Different Operating Parameters129
6.5 Review of Results129
6.6 Conclusions135
References136
Chapter 7. LIFE ESTIMATION OF ROLLING-ELEMENT BEARINGS DUE TO THE EFFECT OF CURRENT LEAKAGE139
7.1 General139
7.2 Theoretical Analysis of Life Estimation of Roller Bearings140
7.3 Theoretical Analysis of Life Estimation of Ball Bearings143
7.4 Capacitive Effect of Rolling-Element Bearings147
7.5 Thermal Stresses Due to Thermal Transients on Rolling-Element Track Surfaces of Races151
7.6 Determination of Number of Cycles Before the Initiation of Slip Bands and Craters Formation on R152
7.7 Discussion of Results155
7.8 Conclusions158
References159
Chapter 8. ANALYSIS OF CAPACITIVE EFFECT OF ROLLER BEARINGS ON REPEATED STARTS AND STOPS OF A MACHIN165
8.1 Introduction165
8.2 Theoretical Analysis to Accumulate and Discharge of the Accumulated Charges165
8.3 Theoretical Data172
8.4 Results and Discussion on Shaft Rotations for Charge Accumulation/Discharge and the Formation of173
8.5 Conclusions174
References175
Chapter 9. EFFECT OF CURRENT LEAKAGE ON ELECTRO-ADHESION FORCES IN ROLLING FRICTION AND MAGNETIC FLU179
9.1 General179
9.2 Introduction180
9.3 Theoretical Model and Approach for Determination of Field Strength182
9.4 Field Strength on Track Surface of Races and Rolling-Elements182
9.5 Magnetic Flux Density on Bearing Surfaces187
9.6 Electro-Adhesion Forces191
9.7 Experimental Facilities and Investigations192
9.8 Test Conditions and Procedure193
9.9 Theoretical and Experimental Data on Flux Density196
9.10 Discussion on Investigations198
9.11 Conclusions204
References205
Chapter 10. TIME SPAN FOR DEVELOPMENT OF FLUTES AFTER THE APPEARANCE OF SLIP BANDS ON THE TRACK SURF211
10.1 General211
10.2 Introduction212
10.3 Background of Electric Current Damage and the Formation of Slip Bands/Corrugations212
10.4 Theoretical Analysis for Energy Requirement for the Appearance of Corrugations214
10.5 Experimental Investigations and Other Related Aspects217
10.6 Comparison of Theoretical and Experimental Data218
10.7 Discussion on Energy and Time Required for the Appearance of Corrugations219
10.8 Conclusions221
References221
Chapter 11. APPEARANCE OF CRATERS ON TRACK SURFACE OF ROLLING-ELEMENT BEARINGS BY SPARK EROSION225
11.1 General225
11.2 Introduction226
11.3 Background and Principle Involved in the Formation of Craters226
11.4 Theoretical Analysis for Energy Requirement Leading to the Formation of Craters227
11.5 Experimental Investigations234
11.6 Data Deduction and Discussion on Energy & Time Required for the Formation of Craters235
11.7 Conclusions239
References240
Chapter 12. APPEARANCE AND EFFECT OF LOCALIZED ELECTRIC CURRENT IN ROLLING-ELEMENT BEARINGS243
12.1 General243
12.2 Introduction243
12.3 Bearing Arrangement and Nature of Bearing Failure244
12.4 Investigations, Observations and Data Collection245
12.5 Theoretical Model and Approach to Determine the Flow of Localized Current in a Bearing247
12.6 Field Strength on the Track Surface of Races and Rolling-Elements250
12.7 Magnetic Flux Density251
12.8 Determination of Time Span for the Appearance of Flutes on the Track Surfaces251
12.9 Data Analysis252
12.10 Results and Discussion on the Localized Current, the Flux Density, Time Span and Mechanism of253
12.11 Conclusions256
References256
Chapter 13. ALTERNATIVE APPROACHES TO DETERMINATION OF STIFFNESS OF ROLLING-ELEMENT BEARINGS261
13.1 General261
13.2 Introduction261
13.3 Theoretical Analysis to Determination of Stiffness of Roller Bearing262
13.4 Theoretical Analysis to Determination of Stiffness of Ball Bearing273
13.5 Conclusions283
References283
Chapter 14. FAILURE DIAGNOSIS AND INVESTIGATIONS OF ROLLING-ELEMENT BEARINGS DUE TO UNFORESEEN CAUSE287
14.1 General287
14.2 Introduction287
14.3 Bearing Arrangement and Nature of Bearing Failure288
14.4 Investigations, Observations and Data Collection289
14.5 Results and Discussion293
14.6 Conclusions297
References298
Chapter 15. ELECTRICAL PARAMETERS OF A CYLINDRICAL HYDRODYNAMIC JOURNAL BEARING AND REDUCTION IN ITS301
15.1 Introduction301
15.2 Theoretical Determination of Electrical Parameters of Cylindrical Hydrodynamic Journal Bearings302
15.3 Optimum Clearance Ratios and Safe Load-Carrying Capacity307
15.4 Theoretical Analysis of the Estimation of Bearing Life Under the Influence of the Shaft Voltage308
15.5 Data of Theoretical Analysis311
15.6 Discussion on Theoretical Analysis312
15.7 Damages Resulting from Shaft Voltages320
15.8 Conclusions321
References322
Chapter 16. ANALYSIS OF CAPACITIVE EFFECT OF JOURNAL BEARINGS ON REPEATED STARTS AND STOPS OF A MACH325
16.1 Introduction325
16.2 Theoretical Analysis Pertaining to Repeated Starts and Stops of a Machine327
16.3 Theoretical Model to Determine Number of Cycles for the Appearance of Craters on the Liner Surf332
16.4 Data Deduction335
16.5 Results and Discussion336
16.6 Conclusions339
References340
Chapter 17. ELECTRICAL PARAMETERS AND DYNAMIC COEFFICIENTS OF DIFFERENT MULTI-LOBES AND TILTING-PAD345
17.1 General345
17.2 Introduction345
17.3 Two-Lobe Journal Bearing346
17.4 Three-Lobe Bearing361
17.5 Four-Lobe Bearing374
17.6 Tilting-Pad Journal Bearings387
17.7 Conclusions397
References400
Chapter 18. EVALUATION OF STIFFNESS AND DAMPING COEFFICIENTS OF CYLINDRICAL JOURNAL BEARINGS BY ELEC403
18.1 Introduction403
18.2 Background404
18.3 Theoretical Derivations405
18.4 Bearing Stiffness Coefficients408
18.5 Theoretical Analysis for Damping Coefficients411
18.6 Mathematical Model413
18.7 Determination of Damping and Stiffness Coefficients415
18.8 Results and Discussion417
18.9 Conclusions420
References421
Chapter 19. ELECTRICAL PARAMETERS AND LIFE ESTIMATION OF PIVOTED PAD THRUST BEARINGS UNDER THE INFLU425
19.1 Introduction425
19.2 Theoretical Determination of Capacitance Between Pivoted Pad and Thrust Collar/Runner of a Bear426
19.3 Theoretical Determination of Active Resistance Between Thrust Collar/Runner and a Pivoted Pad428
19.4 Capacitance and Resistance of Thrust Bearings428
19.5 Determination of Capacitive Reactance and Impedance of Hydrodynamic Thrust Bearing, and Between429
19.6 Life Estimation of Pivoted Pad Thrust Bearings429
19.7 Data Deduction From Theoretical Analysis435
19.8 Results and Discussion on Electrical Parameters and Bearing Life437
19.9 Conclusions443
References445
Chapter 20. ANALYSIS OF PIVOTED PAD THRUST BEARINGS ON REPEATED STARTS AND STOPS OF A MACHINE OPERAT451
20.1 Introduction451
20.2 Theoretical Analysis of Repeated Starts and Stops of a Machine453
20.3 Theoretical Model to Determine Number of Cycles for the Appearance of Craters on the Track Surf458
20.4 Data on Repeated Starts/Stops and on the Crater Formation462
20.5 Results and Discussion463
20.6 Conclusions467
References468
Chapter 21. ANALYSIS OF INDUCTIVE EFFECTS OF BEARINGS UNDER THE INFLUENCE OF SHAFT VOLTAGES473
21.1 Introduction473
21.2 Inductance of Bearing Curcuit474
21.3 Analysis of Inductive Effect474
21.4 Data Deduction477
21.5 Discussions478
21.6 Conclusions480
References480
Index483

Book details

Vendor Elsevier S & T
SKU 9780444518804
ISBN-13 9780080521589
Author Prashad, H.
Category Technology & Engineering
Subject Mechanical

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This book summarises work done and experience gained over the past three decades in the area of tribology in electrical environments. It takes a close look at behaviour and response characteristics of rolling-element, and hydrodynamic journal & thrust bearings working under the influence of electrical current. Detailed analysis plugs the existing knowledge gaps in the area of tribology in electrical environments. This is because the genesis of intermolecular forces during tribological interaction involves electrostatic attraction or repulsion that creates electro-dynamic, magnetic and exchange forces between atoms. Therefore all tribological phenomena occurring in any interacting system is electrical in nature.

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