Electric Motor Control

Front Cover......Page 1
Title Page......Page 4
Copyright......Page 5
Contents......Page 6
Preface......Page 9
SECTION 1: Introduction......Page 12
MOTOR CONTROL INSTALLATION CONSIDERATIONS......Page 14
PURPOSE OF CONTROLLER......Page 16
MANUAL CONTROL......Page 17
REMOTE AND AUTOMATIC CONTROL......Page 18
STARTING AND STOPPING......Page 21
SPEED CONTROL OF MOTORS......Page 22
PROTECTIVE FEATURES......Page 23
CLASSIFICATION OF AUTOMATIC MOTOR STARTING CONTROL SYSTEMS......Page 24
Study Questions......Page 26
FRACTIONAL HORSEPOWER MANUAL MOTOR STARTERS......Page 28
MANUAL PUSH-BUTTON LINE VOLTAGE STARTERS......Page 30
THERMAL OVERLOAD PROTECTION......Page 32
Study Questions......Page 33
MAGNETIC STARTERS VERSUS MANUAL......Page 34
STARTER ELECTROMAGNETS......Page 35
SHADED POLE PRINCIPLE......Page 37
MAGNET COIL......Page 38
MOTOR OVERHEAT......Page 39
OVERLOAD CONTACTS......Page 49
AC MAGNETIC STARTERS......Page 50
AC COMBINATION STARTERS......Page 51
VACUUM CONTACTORS......Page 54
NEMA AND IEC......Page 55
Study Questions......Page 57
SECTION 2: Circuit Layout, Connections, and Symbols......Page 60
UNIT 4: Symbols......Page 62
SENSING DEVICES......Page 66
EXPLANATION OF COMMON SYMBOLS......Page 69
Study Questions......Page 71
LINE DIAGRAMS AND WIRING DIAGRAMS......Page 74
THREE-WIRE CONTROL......Page 77
TARGET TABLES......Page 79
MOTOR NAMEPLATE DATA AND WIRING INTERPRETATION......Page 80
MOTOR POWER AND GREATER EFFICIENCY......Page 82
REVERSING A SINGLE-PHASE MOTOR WITH A DRUM SWITCH......Page 83
Study Questions......Page 87
SECTION 3: Control Pilot Devices......Page 90
PUSH BUTTONS......Page 92
SELECTOR SWITCHES......Page 94
CONTROL STATIONS......Page 95
Study Questions......Page 96
CONTROL RELAYS......Page 98
SOLID-STATE RELAY......Page 101
SURGE PROTECTION......Page 102
THERMOSTAT RELAY......Page 104
Study Questions......Page 105
CONTACTORS......Page 106
AC MECHANICALLY HELD CONTACTORS AND RELAYS......Page 109
Study Questions......Page 112
PNEUMATIC TIMERS......Page 114
MOTOR-DRIVEN TIMERS......Page 116
CAPACITOR TIME LIMIT RELAY......Page 117
ELECTRONIC TIMERS......Page 118
SELECTING A TIMING RELAY......Page 120
Study Questions......Page 122
UNIT 10: Pressure Switches and Regulators......Page 124
Study Questions......Page 127
UNIT 11: Float Switches......Page 128
MERCURY BULB FLOAT SWITCH......Page 130
Study Questions......Page 132
UNIT 12: Flow Switches......Page 134
Study Questions......Page 137
LIMIT SWITCHES......Page 138
SOLID-STATE PROXIMITY SWITCHES......Page 139
Study Questions......Page 144
UNIT 14: Phase Failure Relays......Page 146
LARGE MOTOR CURRENT MONITOR......Page 147
Study Questions......Page 148
TWO-WAY SOLENOID VALVES......Page 150
FOUR-WAY SOLENOID VALVES......Page 151
Study Questions......Page 153
SOLID-STATE TEMPERATURE CONTROL SYSTEMS......Page 154
Study Questions......Page 156
SECTION 4: Basic Control Circuits......Page 158
UNIT 17: Two-Wire Controls......Page 160
Study Questions......Page 162
THREE-WIRE CONTROLS......Page 164
ALARM SILENCING CIRCUIT......Page 165
SEPARATE CONTROL......Page 166
Study Questions......Page 168
UNIT 19: Hand-Off Automatic Controls......Page 170
Study Questions......Page 172
UNIT 20: Multiple Push-Button Stations......Page 174
Study Questions......Page 175
MECHANICAL INTERLOCK......Page 176
PUSH-BUTTON INTERLOCK......Page 177
AUXILIARY CONTACT INTERLOCK......Page 179
Study Questions......Page 182
AUTOMATIC SEQUENCE CONTROL......Page 184
LOGIC CONCEPT AND CONTROL FUNCTION......Page 186
SOLID-STATE LOGIC ELEMENTS......Page 187
Study Questions......Page 190
JOGGING CONTROL CIRCUITS......Page 192
JOGGING USING A CONTROL RELAY......Page 193
Study Questions......Page 196
UNIT 24: Time-Delay, Low-Voltage Release Relay......Page 198
CONSTRUCTION AND OPERATION......Page 199
Study Questions......Page 200
SECTION 5: AC Reduced Voltage Starters......Page 202
THE MOTOR......Page 204
TYPICAL STARTING METHODS......Page 208
Study Questions......Page 209
PRIMARY RESISTOR-TYPE STARTERS......Page 210
Study Questions......Page 215
UNIT 27: Autotransformer Starters......Page 216
Study Questions......Page 220
UNIT 28: Part Winding Motor Starters......Page 222
TWO-STEP STARTING......Page 223
OVERLOAD PROTECTION......Page 224
Study Questions......Page 226
APPLICATIONS......Page 228
OPERATION......Page 229
CLOSED TRANSITION STARTING......Page 230
Study Questions......Page 233
THE NEED FOR SOLID-STATE CONTROL......Page 234
SOLID-STATE REDUCED VOLTAGE MOTOR STARTING......Page 235
SOLID-STATE CONTROL WITH EXISTING MAGNETIC DEVICES......Page 237
ENERGY SAVING......Page 238
APPLICATION......Page 240
Study Questions......Page 241
SECTION 6: Three-Phase, Multispeed Controllers......Page 242
THE MOTOR......Page 244
CONTROLLERS......Page 245
Study Questions......Page 248
UNIT 32: Two-Speed, One-Winding (Consequent Pole) Motor Controller......Page 250
TWO-SPEED STARTER WITH REVERSING CONTROLS......Page 254
Study Questions......Page 257
COMPELLING RELAYS......Page 258
Study Questions......Page 262
SECTION 7: Wound Rotor (Slip Ring) Motor Controllers......Page 264
UNIT 34: Wound Rotor Motors and Manual Speed Control......Page 266
Study Questions......Page 270
UNIT 35: Push-Button Speed Selection......Page 272
Study Questions......Page 274
UNIT 36: Automatic Acceleration for Wound Rotor Motors......Page 276
AUTOMATIC ACCELERATION WITH REVERSING CONTROL......Page 277
AUTOMATIC ACCELERATION USING FREQUENCY RELAYS......Page 278
Study Questions......Page 280
UNIT 37: Automatic Speed Control for Wound Rotor Motors......Page 282
Study Questions......Page 284
SLIP POWER RECOVERY......Page 286
POWER FACTOR CORRECTION CAPACITORS......Page 287
Study Questions......Page 289
SECTION 8: Synchronous Motor Controls......Page 290
UNIT 39: Synchronous Motor Operation......Page 292
POWER FACTOR CORRECTION BY SYNCHRONOUS MOTOR......Page 293
BRUSHLESS SYNCHRONOUS MOTORS......Page 294
Study Questions......Page 296
UNIT 40: Push-Button Synchronizing......Page 298
Study Questions......Page 301
UNIT 41: Timed Semiautomatic Synchronizing......Page 302
Study Questions......Page 304
ROTOR CONTROL EQUIPMENT......Page 306
SUMMARY OF AUTOMATIC STARTER OPERATION......Page 309
BRUSHLESS SOLID-STATE MOTOR EXCITATION......Page 311
Study Questions......Page 312
SECTION 9: Direct-Current Controllers......Page 314
MOTOR CONSTRUCTION......Page 316
TYPES OF DC MOTORS......Page 317
SPEED CONTROL......Page 318
STARTING THE MOTOR......Page 320
Study Questions......Page 321
UNIT 44: Use of Reduced Voltage for Starting......Page 322
Study Questions......Page 324
UNIT 45: Across-the-Line Starting......Page 326
Study Questions......Page 328
COUNTER EMF CONTROLLER......Page 330
FIELD ACCELERATING RELAY......Page 331
DEFINITE TIME CONTROL STARTING......Page 332
Study Questions......Page 334
STARTING THE MOTOR......Page 336
DC ADJUSTABLE SPEED CONTROL FROM SINGLE-PHASE AC......Page 337
DC ADJUSTABLE SPEED CONTROL,THREE PHASE......Page 338
SELF-TEST DIAGNOSTICS......Page 340
Study Questions......Page 343
SECTION 10: Methods of Deceleration......Page 344
PLUGGING SWITCHES AND APPLICATIONS......Page 346
PLUGGING WITH THE USE OF A TIMING RELAY......Page 348
ALTERNATE CIRCUITS FOR PLUGGING SWITCH......Page 349
ANTIPLUGGING PROTECTION......Page 350
Study Questions......Page 353
UNIT 49: Electric Brakes......Page 354
DC MAGNETIC BRAKES......Page 355
Study Questions......Page 357
UNIT 50: Dynamic and Regenerative Braking......Page 358
DYNAMIC BRAKING FOR LIGHT-DUTY EQUIPMENT......Page 360
DYNAMIC BRAKING FOR A SYNCHRONOUS MOTOR......Page 361
Study Questions......Page 363
APPLICATION......Page 364
SEQUENCE OF OPERATION OF AN ELECTRIC BRAKING CIRCUIT......Page 365
ELECTRIC BRAKING FOR A WOUND ROTOR MOTOR......Page 367
Study Questions......Page 370
SECTION 11: Motor Drives......Page 372
DIRECTLY COUPLED DRIVE INSTALLATION......Page 374
PULLEY DRIVES......Page 376
Study Questions......Page 378
UNIT 53: Gear Motors......Page 380
Study Questions......Page 382
UNIT 54: Variable-Frequency Mechanical Drives......Page 384
Study Questions......Page 386
VARIABLE-FREQUENCY DRIVE OPERATING PRINCIPLES......Page 388
Study Questions......Page 395
ELECTRICALLY CONTROLLED MAGNETIC CLUTCHES......Page 396
MAGNETIC DRIVES......Page 398
Study Questions......Page 400
UNIT 57: DC Variable-Speed Control—Motor Drives......Page 402
MODIFICATIONS......Page 404
Study Questions......Page 406
PROGRAMMABLE CONTROLLERS......Page 408
INSTALLATION......Page 412
PROGRAMMER TERMINAL......Page 413
MOTOR CONTROL CENTER......Page 416
STEPPER MOTORS......Page 418
SELF-SYNCHRONOUS (SELSYN) TRANSMISSION SYSTEM......Page 419
Study Questions......Page 422
SECTION 12: Troubleshooting......Page 424
MOTOR STARTUP......Page 426
MOTOR MOUNTS......Page 427
TROUBLESHOOTING BASICS......Page 428
HOW TO FIND AN INTERMITTENT FAULT......Page 430
SOLID-STATE EQUIPMENT......Page 436
Study Questions......Page 437
SAFETY PRECAUTIONS......Page 438
VOLTMETER BASICS......Page 439
TEST PROCEDURE EXAMPLE 1......Page 441
TEST PROCEDURE EXAMPLE 2......Page 443
TEST PROCEDURE EXAMPLE 3......Page 445
Study Questions......Page 450
Appendix A: Motor Types and Line Diagrams......Page 452
Appendix B: Power Supplies......Page 454
Glossary......Page 456
Index......Page 464