Torsion A straining action produced by couples that act normal to the axis of a member, identified by a twisting deformation. Transmission System by which power is transmitted from the engine to a shaft or axle. Trigonometric function The real-valued functions such as sin(x), tan(x), and cos(x) obtained from studying certain ratios of the sides of a right triangle. Also known as circular functions. Trigonometric leveling A method of determining the difference of elevation between two points by using the principles of triangulation and trigonometric functions. Two-way clutch A clutch with a tooth profile (square or tapered) provides positive power transmission in both directions of rotation. Vane Casting on the backside of the impeller that reduces the pressure acting on the fluid behind the impeller. V-belt An endless V-shaped belt with a trapezoidal cross-section that runs in a pulley having a V-shaped groove. Vibration Continuous periodic change in a displacement with respect to a fixed reference. Vibration/balance analyzer A device that detects the level of imbalance, misalignment, etc., in a rotating part based on the measurement of vibration signals. Viscosity The resistance that a gaseous or liquid system offers to flow when it is subjected to a shear stress. Also known as flow resistance or internal friction. Volute Spiral part of a pump casing that accepts the fluid from the impeller and carries it to the outlet. Keith Mobley /Maintenance Fundamentals Final Proof 15.6.2004 6:28pm page 414 414 Maintenance Fundamentals Wear Deterioration of a surface due to material removal caused by relative motion between it and another part. Whip Phenomenon caused by pulsating loads in the drive system. Excessive belt whip is usually more common on long-center applications where the distance between the two pulley shafts is great. Whip Radial shaft movement. Also referred to as deflection. Whole depth The total height of a height of a tooth or the total depth of a tooth space. Work Transference of energy that occurs when a force is applied to a body that is moving in such a way that the force has a component in the direction of the body’s motion. Working depth The depth of tooth engagement of two matching gears. It is the sum of their addendum. Worm A shank having at least one complete tooth (thread) around the pitch surface. Worm gear A gear with teeth cut on an angle to be driven by a worm; used to connect nonparallel, nonintersecting shafts. Keith Mobley /Maintenance Fundamentals Final Proof 15.6.2004 6:28pm page 415 Glossary 415 INDEX A Aerodynamic instability, 312 Alignment, 71, 74 Anti-friction bearings, 138 Availability, 6 Axial fans, 300 B Backlash, 212, 225 Baghouses, 317, 328 Balancing, 119 standards, 122 Ball valves, 266 Bearings, 125, 261 failures, 162 materials, 149 selection, 165 types, 126 Bevel gears, 213 Blowers, 315 Butterfly valves, 268 C Calibration, 17, 52 standards, 52 Cavitation, 353, 356 Centrifugal compressors, 231 fans, 299, 213 pumps, 331 troubleshooting, 357 Chain conveyors, 290 Cleanliness, 30 Cocked rotor, 114 Compressor performance, 235, 243, 251 Computerized maintenance management systems, 24 Condition monitoring, 10, 26 Configuration management, 57, 63 Conveyor installation, 289, 296 performance, 288, 294 Coordination, 22, 42 Corrective maintenance, 9 Coupled imbalance, 118 Couplings, 171 alignment, 74 installation, 187 selection, 183 types, 171 Cyclone separators, 325, 328 D Decommissioning, 65 Dust collection systems, 318 Dynamic imbalance, 116, 118 Keith Mobley /Maintenance Fundamentals Final Proof 15.6.2004 6:29pm page 416 416 E Effective maintenance, 12 Engineering change management, 60 Equipment life, 7 reliability, 27 Estimating, 19 materials, 22, 39 time, 21, 37, 38 F Fan installation, 307 performance, 302 troubleshooting, 312 Fixed bearings, 133 Fixed interval maintenance, 11, 45 Flexible couplings, 172 Fluid power, 276 Functional specifications, 63 G Gate valves, 267 Gears, 201 dynamics, 220 failures, 220 pitch calculations, 208 pumps, 350 troubleshooting, 226 Globe valves, 269 H Helical gears, 215, 225 lobe compressors, 240 Herringbone gears, 219, 226 I Imbalance, 115, 265 Improvement process, 27 Inspections, 12, 20, 37, 46, 190 control records, 53 intervals, 52 J Journal bearings, 133 K Key stress calculations, 197 Keys and keyways, 115, 185, 192 Keyway manufacturing tolerances, 196 L Lubrication, 15, 31, 46, 152, 188, 189, 263 codes, 49 M Maintenance costs, 1 engineer, 55 improvement 8 management, 24, 37 manager, 20 philosophy, 7, 36 planner, 23 policies, 2 Management effectiveness, 1 Mean-time-between-failures, 8 Mean-time-to-failure, 4, 14 Mechanical imbalance, 3, 4 Mechanical seals, 341 Miter gears, 213 N Non-destructive testing, 112 O Oil whip, 6 Oil whirl, 6 Operating condition, 169 dynamics, 6 P Perfect alignment, 5 Personnel, 74 Plain bearings, 31 Planning, 131, 155 Pneumatic conveyors, 287, 318 Positive displacement compressor, 238 fans, 315 pumps, 343, 361 Keith Mobley /Maintenance Fundamentals Final Proof 15.6.2004 6:29pm page 417 Index 417 Precision balancing, 40 Predictive maintenance, 19, 35 Preventive maintenance, 4 Prioritizing, 4, 9, 10, 20, 22, 25, 31, 35, 37, 43, 45 Procedure development, 121 Process instability, 316 valves, 266 Procurement package, 68 Propeller fans, 299 R Radial bearings, 63 Reactive maintenance, 133 Record keeping, 3, 10 Reciprocating compressors, 246, 262 pumps, 344, 362 Reliability, 24 engineering, 27, 66 Rigid couplings, 8 Role of maintenance, 171 Rolling element bearings, 6 Rotary compressors, 238, 257, 261 pumps, 340 Run-to-failure management, 138, 153, 156, 160 S Scheduled maintenance, 2 Scheduling, 10, 45 Screw compressors, 240 conveyors, 292 SFMEA, 22, 35, 39 Shaft alignment, 30 stress calculations, 71 Simplified failure modes and effects analysis, 198 Soft foot, 30 Spares inventory, 82 Spectrometric oil analysis, 7 Spur gears, 13 Standard procedures, 201 Static imbalance, 37, 64, 66 T Thermic growth, 116 Thermodynamics, 236 Thermography, 106 Thresholds, 5, 6 Thrust bearings, 5, 6 Tribology, 14 U Unscheduled breakdowns, 133 Utilization of maintenance workforce, 5 V Valve actuators, 283 installation, 274, 278 performance, 271, 278 troubleshooting, 285 Vibration monitoring, 7 Visual inspection, 5, 6 W Worm gears, 216 Keith Mobley /Maintenance Fundamentals Final Proof 15.6.2004 6:29pm page 418 418 Index . 300 B Backlash, 21 2, 22 5 Baghouses, 317, 328 Balancing, 119 standards, 122 Ball valves, 26 6 Bearings, 125 , 26 1 failures, 1 62 materials, 149 selection, 165 types, 126 Bevel gears, 21 3 Blowers, 315 Butterfly. 26 7 Gears, 20 1 dynamics, 22 0 failures, 22 0 pitch calculations, 20 8 pumps, 350 troubleshooting, 22 6 Globe valves, 26 9 H Helical gears, 21 5, 22 5 lobe compressors, 24 0 Herringbone gears, 21 9, 22 6 I Imbalance,. /Maintenance Fundamentals Final Proof 15.6 .20 04 6 :29 pm page 416 416 E Effective maintenance, 12 Engineering change management, 60 Equipment life, 7 reliability, 27 Estimating, 19 materials, 22 ,