Handbook of Electrical Engineering

410 HANDBOOK OF ELECTRICAL ENGINEERING In this case the maximum rms value ofIis, Imax= Id π √ 3 2 2 = √ 6 π Id ( 15. 11 ) 15.2.4 ...

HARMONIC VOLTAGES AND CURRENTS 411 The motor running details are, Running output power 217.8 kW Running voltage 323.3 volts Runn ...

412 HANDBOOK OF ELECTRICAL ENGINEERING b 1 = sin( 2 × 66. 753 )−sin( 2 × 66. 215 )− 2 × 0. 00939 2 ( 0. 4033 − 0. 3947 ) = 0. 72 ...

HARMONIC VOLTAGES AND CURRENTS 413 Note, a ‘rule-of-thumb’ expression for the power factor is, cos Ø 1  0. 7 ωo ωn + 0. 2 Where ...

414 HANDBOOK OF ELECTRICAL ENGINEERING The value of the fundamental coefficientb 1 is, b 1 = 1 π ( 4 √ 3 2 ) = 2 √ 3 π 15.3.2 Si ...

HARMONIC VOLTAGES AND CURRENTS 415 Figure 15.5 Trapezoidal current in the supply side of a six-pulse thyristor bridge, with the ...

416 HANDBOOK OF ELECTRICAL ENGINEERING The average value of the waveform is zero because it is symmetrical about the Y-axis, and ...

HARMONIC VOLTAGES AND CURRENTS 417 Therefore the commutating reactance= 2. 0 × 0. 245 × 0. 4306 =0.211 ohms/phase=Xc Vd=Vdocosα− ...

418 HANDBOOK OF ELECTRICAL ENGINEERING Figure 15.6 Circuit diagram of a 12-pulse thyristor bridge. For example, leti 1 =I sinωta ...

HARMONIC VOLTAGES AND CURRENTS 419 two parts are, Part 1. For the 180◦rectangle waveform, bn 180 = 4 πn , the fundamentalb 1180 ...

420 HANDBOOK OF ELECTRICAL ENGINEERING Figure 15.7 Primary line currents in the transformers feeding a 12-pulse thyristor bridge ...

HARMONIC VOLTAGES AND CURRENTS 421 The effect of the commutation angleuon the 180◦,60◦and supply current waveforms is the same a ...

422 HANDBOOK OF ELECTRICAL ENGINEERING Figure 15.10 Waveform of the load current in a single-phase quazi-square-wave inverter. a ...

HARMONIC VOLTAGES AND CURRENTS 423 The inverter bridge switches the DC voltage across the lines of the motor. The waveform appea ...

424 HANDBOOK OF ELECTRICAL ENGINEERING For motors that normally operate at slips in the order of 0.5% to 3.0% the values ofsnfor ...

HARMONIC VOLTAGES AND CURRENTS 425 Assume the inverter equivalent output phase-to-neutral voltage consists of a 180◦rectangle wa ...

426 HANDBOOK OF ELECTRICAL ENGINEERING The combined admittance of the rotor and magnetising impedances become, Ym 2 = −j nXm + R ...

HARMONIC VOLTAGES AND CURRENTS 427 Table 15.4. Harmonic rms currents and voltages in a star-wound induction motor that is fed fr ...

428 HANDBOOK OF ELECTRICAL ENGINEERING Figure 15.12 Instantaneous voltages and currents in an induction motor supplied from a vo ...

HARMONIC VOLTAGES AND CURRENTS 429 The supply voltage becomes, V 15 =I 15 Z1m2 =− 110. 95 √ 2 ( 0. 00878 +j 0. 7711 ) =− 0. 6888 ...