CONTENTS 



PAGE 



89. Three-pha- utncrs 203 



\uto-transformers 206 



Transformer ( 1 onnections 211 



!'he V -connection 213 



! he Scott orT-connection 214 



oust ant-current Transformers 217 



Instrunu'iit Transformers 220 



95. Electrical Measurements at High Voltages 220 



96. Potential Transformers 221 



97. Current Transformers . .221 



CHAPTER VIII 



THK INDUCTION MOTOR 225 



98. Principle 225 



99. The Alternating-current Rotating Field 227 



100. Rotating Fields in Drum-wound Machines 231 



101. Synchronous Speed; Slip 235 



102. Rotor Frequency and Induced E.m.f 236 



103. Alternating-current Torque 237 



104. The Squirrel-cage Motor 241 



105. Operating Characteristics of the Squirrel-cage Motor. . . . 243 



106. Starting Squirrel-cage Motors 249 



107. The Wound-rotor Induction Motor 253 



108. The Induction Motor Air-gap 258 



109. Speed Control of Induction Motors 258 



110. The Induction Generator 265 



111. The Circle Diagram 270 



112. The Measurement of Slip 273 



1 13. The Induction Regulator 275 



CHAPTER IX 



MOTORS 279 



114. The Series Motor 279 



Iir. The Repulsion Motor 286 



116. Single-phase Induction Motor 292 



117. He:u-t ions in a Single-phase Induction Motor 294 



1 1 s. The Operation of the Polyphase Motor as a Single-phase 



Motor 296 



119. Starting Single-phase Induction Motors 296 



12(1. The Induction Motor as a Phase Converter 300 



121. The Repulsion-induction (RI) Motor 303 



122. The Wagner Type BK, Unity Power-factor Motor. . . . . 304 



