None
generator and synchronous converter 379 Over-compound generator, operation of 134 use of shunt for series field on 108 Over-load release 174 Pancake coil, use of in transformer 283 Panel of a switchboard 424 Parallel operation of a-c. generators 260 c-c. generators 142-146 Period, meaning of term 196 natural, of an a-c. circuit 227 of a synchronous motor 328 Permeabihty, magnetic 19 Phase characteristics of a synchronous motor 316 Phase displacement of voltage and current 203 Physiological effect of an electrical current 2 Pitch of armature windings 84 Pole shoe, use of 35 Pole tips 35 Poles, commutating 36, 119 material and construction 32, 124 Polyphase circuit, metering power in a 404 machinery compared to single phase / 400 power, advantage over single phase 398 transformation 402 Potential, meaning of the term 14 difference of 14 Power, active in an a-c. circuit 205 Power factor of an a-c. circuit 204 Power, formula for, in a c-c. circuit 13 in an a-c. circuit 204 , measurement of, in an a.c. circuit 208 reactive, in an a-c. circuit 204 unit of 13 " Pump-back " test 193 462 INDEX PAGE Quadrature current or e.m.f 205 Quantity of electricity, unit of 10 Rating of a-c. machinery 251 Radiation, effect of, on capacity of a machine 139 Reactance 215 Reaction, armature, compensation for, in c-c. machines 125 distortion of field by 166 effect of, on commutation 122 on speed of a motor 165 on voltage of a generator 130 in c-c. machines 22 in polyphase alternator 249-250 in single-phase alternator 244 limits length of air gap 43 Reaction, capacity 220 inductance 213 resistance 211 Reactive current or e.m.f , 204 power 205 Rectifier, mercury arc 391 vibrating 389 Regulation of a generator 135 of a transformer 295 voltage, used with alternators 255 Relay, over-load, time-Umit 415 Release, no-voltage 175 over-load 174 Reluctance of a magnetic circuit 16 Repulsion motor 362 Resistance, dependence upon dimensions of conductor G dependence upon temperature 6 effective, of an a-c. circuit 209 general conception of 5 of copper wires, table of 8 Resistance drop in a c-c. armature, calculation of 101 leads in a single-phase series motor 359 Resonance in an a-c. circuit 226 Reversibility of motor and generator 25 Rheostat, field 105 motor starting 172 cfilculation of .,.,.. 173 INDEX ;463 PAGE Ribbon wound field coil 73 Rotary converter 367 Rotor, of an induction motor 331 » •■■! Scott connection of transformers 402 Series generator, characteristics of a 131 Series motor, characteristics of and use 158, 352 Shunt generator, characteristics of 132 motor 151 Shunt, used with series field winding 108 Single-phase induction motor 347 series motor 101 compensating winding for 356 commutation of 358 use of resistance leads 359 Skin effect in solid conductors 211 Slot in armature core, shape of 46 Solution of problems on a-c. circuits 225 Sparking at commutator due to brushes in wrong position 439 insufficient brush pressure 439 open circuited coil 440 over-loaded armature 439 poorly fitted brushes 439 rough surface 436 short circuited coil 439 unequal air gap 440 unequal brush spacing 440 vibration of machine 439 Speed of a motor, effect of variation in line voltage on 167 Speed, no-load, of a motor, calculation of 160 Speed control of motor by field variation 177 by multiple voltage supply line 176 of induction motor 345 of railway motors 179 Speed-load curves for different types of motors 160 Spider, armature 43 commutator 53 Split phase method of starting an induction motor 347 Split pole synchronous converter 387 Starting a machine, precautions to be observed 430 Starting rheostat for a motor 172 "Step-down" and "step-up" transformers 277 464 INDEX PAGE Stray power in a dynamo-electric machine 190 Synchronizing a-c. generators 262 Synchronoscope 263 Synchronous condenser 323 converter, capacity of a 378 compounding 381 construction 367 current in various armature coils 373 heating of coils 376 methods of starting 379 voltage ratio of 369 voltage ratio of tl:e auxiliary poles 369 used for power factor correction 386 motor, equivalent circuit of 321 operation of a 309 phase characteristics •. 316 phase shifting with change of load 325 starting characteristics of 310 Switch, air-break 406 oil-break 407 motor-operated 408 Switchboard, general arrangement of 424 Table of copper wire sizes 8 Temperature coefficient of resistance 6 rise dependent upon ventilation 139 Three phase system, grouping of apparatus 401 metering power 404 weight of copper required, compared to single- phase 398 Three-wire generator 135 system of distribution 136 Time of short circuit for commutation 110 Tirrill regulator 255 Torque acting in a generator 150 acting in a motor 151 calculation of, in a c-c. armature, developed 86, 239 field (see field windings). Y-connected alternator 236 Yoke, material of, in c-c. machinery 32 reluctance of 67 UNIVERSITY OF CALIFORNIA BRANCH OF THE COLLEGE OF AGRICULTURE THIS BOOK IS DUE ON THE LAST DATE STAMPED BELOW i>£ip ;-? 1929 M»N 2 3 1962 UNIVERSITY OF CALIFORNIA LIBRARY. 