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Replace the 28-tooth rotor of Problem 8.7 with a rotor Replace the 28-tooth rotor of Problem 8.7 with a rotor with 26 teeth. a. Phase 1 is excited, and the rotor is allowed to come to rest. If the excitation on phase 1 is removed and excitation is applied to phase 2, calculate the resultant […]

Repeat Problem 7.6 including the saturation effects represented Repeat Problem 7.6 including the saturation effects represented by the saturation curve of Figure. For part (a), set the field current equal to the value required to produce an open-circuit armature terminal voltage of 250 V at 1200r/min. Is this the question you were looking for? If […]

A three-phase, variable-speed induction motor is operated from a A three-phase, variable-speed induction motor is operated from a variable frequency, variable-voltage source which is controlled to maintain constant peak air-gap flux density as the frequency of the applied voltage is varied. The motor is to be operated at constant slip frequency while the motor speed […]

A three-phase, Y-connected, 460-V (line-line), 25-kW, 60-Hz, A three-phase, Y-connected, 460-V (line-line), 25-kW, 60-Hz, four-pole induction motor has the following equivalent-circuit parameters in ohms per phase referred to the stator: R1 = 0.103 R2 = 0.225 X1 = 1.10 X2 = 1.13 Xm = 59.4. The total friction and wind age losses may be assumed […]

A three-phase, eight-pole, 60-Hz, 4160-V, 1250-kW squirrel-cage A three-phase, eight-pole, 60-Hz, 4160-V, 1250-kW squirrel-cage induction motor has the following equivalent-circuit parameters in ohms-per-phase-Y referred to the stator: R1 = 0.212 R2 = 0.348 X1 = 1.87 X2 = 2.27 Xm = 44.6. It is operating from a field-oriented drive system at a speed of 805r/min […]

A three-phase Y-connected ac machine is initially operating A three-phase Y-connected ac machine is initially operating under balanced three-phase conditions when one of the phase windings becomes open-circuited. Because there is no neutral connection on the winding, this requires that the currents in the remaining two windings become equal and opposite. Under this condition, calculate […]

A three-phase two-pole winding is excited by balanced three A three-phase two-pole winding is excited by balanced three-phase 60-Hz currents as described by Eqs. 4.23 to 4.25. Although the winding distribution has been designed to minimize harmonics, there remains some third and fifth spatial harmonics. Thus the phase-a mmf can be written as Fa = […]

A three-phase induction motor runs at almost 1198 r/min at and 1112 r/min at full load when supplied from a 60-Hz, three-phase source. a. How many poles does this motor have? b. What is the slip in percent at full load? c. What is the corresponding frequency of the rotor currents? d. What is the […]

A three-phase linear ac motor has an armature winding of A three-phase linear ac motor has an armature winding of wavelength 25 cm. A three-phase balanced set of currents at a frequency of 100 Hz is applied to the armature. a. Calculate the linear velocity of the armature mmf wave. b. For the case of […]

Figure shows a configuration that can be used to measure the Figure shows a configuration that can be used to measure the magnetic characteristics of electrical steel. The material to be tested is cut or punched into circular laminations which are then stacked (with interspersed insulation to avoid eddy-current formation). Two windings are wound over […]