Preface |
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xiii | |
Acknowledgments |
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xvii | |
Nomenclature |
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xix | |
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1 Introduction to condition monitoring |
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1 | |
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1 | |
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1.2 The need for monitoring |
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4 | |
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1.3 What and when to monitor |
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7 | |
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9 | |
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10 | |
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2 Construction, operation and failure modes of electrical machines |
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13 | |
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13 | |
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2.2 Materials and temperature |
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14 | |
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2.3 Construction of electrical machines |
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16 | |
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2.3.2 Stator core and frame |
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18 | |
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20 | |
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26 | |
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2.4 Structure of electrical machines and their types |
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26 | |
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2.5 Machine specification and failure modes |
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33 | |
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2.6 Insulation ageing mechanisms |
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35 | |
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36 | |
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2.6.5 Environmental ageing |
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38 | |
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2.6.6 Synergism between ageing stresses |
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39 | |
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2.7 Insulation failure modes |
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39 | |
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2.7.2 Stator winding insulation |
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40 | |
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2.7.3 Stator winding faults |
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45 | |
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2.7.4 Rotor winding faults |
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50 | |
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54 | |
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54 | |
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2.8.2 Connection faults (high-voltage motors and generators) |
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54 | |
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2.8.3 Water coolant faults (all machines) |
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56 | |
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56 | |
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56 | |
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3 Reliability of machines and typical failure rates |
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61 | |
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3.3 Failure sequence and effect on monitoring |
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63 | |
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3.4 Typical root causes and failure modes |
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66 | |
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3.7 Typical failure rates and MTBFs |
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4 Instrumentation requirements |
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79 | |
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4.2 Temperature measurement |
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81 | |
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4.3 Vibration measurement |
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88 | |
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4.3.2 Displacement transducers |
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89 | |
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4.3.3 Velocity transducers |
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91 | |
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4.4 Force and torque measurement |
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94 | |
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4.5 Electrical and magnetic measurement |
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97 | |
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4.6 Wear and debris measurement |
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100 | |
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104 | |
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5 Signal processing requirements |
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109 | |
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5.3 High-order spectral analysis |
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115 | |
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116 | |
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5.5 Signal processing for vibration |
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118 | |
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118 | |
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5.5.3 Time averaging and trend analysis |
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120 | |
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121 | |
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6.2 Local temperature measurement |
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127 | |
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6.3 Hot-spot measurement and thermal images |
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132 | |
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134 | |
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7.2 Insulation degradation |
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137 | |
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7.3 Factors that affect detection |
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138 | |
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7.4 Insulation degradation detection |
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142 | |
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7.4.1 Particulate detection: core monitors |
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142 | |
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7.4.2 Particulate detection: chemical analysis |
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146 | |
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7.4.3 Gas analysis off-line |
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148 | |
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7.4.4 Gas analysis on-line |
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149 | |
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7.5 Lubrication oil and bearing degradation |
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152 | |
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7.6 Oil degradation detection |
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153 | |
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7.7 Wear debris detection |
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153 | |
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7.7.2 Ferromagnetic techniques |
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154 | |
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7.7.3 Other wear debris detection techniques |
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8.2.2 Calculation of natural modes |
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161 | |
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8.2.3 Stator electromagnetic force wave |
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164 | |
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8.3 Stator end-winding response |
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167 | |
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8.4.1 Transverse response |
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168 | |
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8.5.2 Rolling element bearings |
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173 | |
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8.6 Monitoring techniques |
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176 | |
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8.6.1 Overall level monitoring |
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177 | |
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8.6.2 Frequency spectrum monitoring |
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179 | |
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8.6.3 Faults detectable from the stator force wave |
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182 | |
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8.6.4 Torsional oscillation monitoring |
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183 | |
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8.6.5 Shock pulse monitoring |
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187 | |
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189 | |
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9 Electrical techniques: current, flux and power monitoring |
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193 | |
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9.2 Generator and motor stator faults |
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193 | |
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9.2.1 Generator stator winding fault detection |
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193 | |
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9.2.2 Stator current monitoring for stator faults |
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193 | |
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9.2.3 Brushgear fault detection |
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194 | |
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9.2.4 Rotor-mounted search coils |
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194 | |
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9.3 Generator rotor faults |
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194 | |
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9.3.2 Earth leakage faults on-line |
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195 | |
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9.3.3 Turn-to-turn faults on-line |
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196 | |
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9.3.4 Turn-to-turn and earth leakage faults off-line |
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204 | |
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207 | |
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207 | |
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9.4.2 Airgap search coils |
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207 | |
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9.4.3 Stator current monitoring for rotor faults |
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207 | |
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9.4.4 Rotor current monitoring |
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210 | |
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9.5 Generator and motor comprehensive methods |
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212 | |
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213 | |
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217 | |
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217 | |
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9.5.5 Shaft voltage or current |
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219 | |
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9.5.6 Mechanical and electrical interaction |
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221 | |
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9.6 Effects of variable speed operation |
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221 | |
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224 | |
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224 | |
10 Electrical techniques: discharge monitoring |
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229 | |
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229 | |
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10.2 Background to discharge detection |
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229 | |
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10.3 Early discharge detection methods |
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231 | |
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10.3.1 RF coupling method |
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231 | |
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10.3.2 Earth loop transient method |
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233 | |
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10.3.3 Capacitive coupling method |
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235 | |
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10.3.4 Wideband RF method |
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236 | |
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10.3.5 Insulation remanent life |
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236 | |
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238 | |
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10.5 Modern discharge detection methods |
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239 | |
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241 | |
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241 | |
11 Application of artificial intelligence techniques |
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245 | |
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246 | |
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11.4 Artificial neural networks |
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253 | |
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11.4.2 Supervised learning |
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254 | |
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11.4.3 Unsupervised learning |
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256 | |
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260 | |
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261 | |
12 Condition-based maintenance and asset management |
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263 | |
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263 | |
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12.2 Condition-based maintenance |
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263 | |
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265 | |
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265 | |
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267 | |
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268 | |
Appendix Failure modes and root causes in rotating electrical machines |
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269 | |
Index |
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277 | |