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 […]
Figure shows in schematic cross section a salient-pole Figure shows in schematic cross section a salient-pole synchronous machine having two identical stator windings a and b on a laminated steel core. The salient-pole rotor is made of steel and carries a field winding f connected to slip rings. Because of the non-uniform air gap, the […]
Figure shows an inductor wound on a laminated iron core of Figure shows an inductor wound on a laminated iron core of rectangular cross section. Assume that the permeability of the iron is infinite. Neglect magnetic leakage and fringing in the two air gaps (total gap length = g). The N-turn winding is insulated copper […]
The design of a four-pole, three-phase, 230-V, 60-Hz induction The design of a four-pole, three-phase, 230-V, 60-Hz induction motor is to be based on a stator core of length 21 cm and inner diameter 9.52 cm. The stator winding distribution which has been selected has a winding factor kw = 0.925. The armature is to […]
Figure shows a two-phase hybrid stepping motor with castleated p Figure shows a two-phase hybrid stepping motor with castleated poles on the stator. The rotor is shown in the position it occupies when current is flowing into the positive lead of phase 1. a. If phase one is turned off and phase 2 is excited […]
Field-oriented torque control is to be applied to the permanent- Field-oriented torque control is to be applied to the permanent-magnet synchronous motor of Problem 11.18. If the motor is to be operated at 4000 r/min at rated terminal voltage, calculate the maximum torque and power which the motor can supply and the corresponding values of […]
Figure shows a circularly symmetric system in which a moveable Figure shows a circularly symmetric system in which a moveable plunger (constrained to move only in the vertical direction) is supported by a spring of spring constant K = 5.28 N/m. The system is excited by a samarium-cobalt permanent-magnet in the shape of a washer […]
Design calculations show the following parameters for a three-ph Design calculations show the following parameters for a three-phase, cylindrical-rotor synchronous generator: Phase-a self-inductance Laa = 4.83mH. Armature leakage inductance Lal = 0.33mH. Calculate the phase-phase mutual inductance and the machine synchronous inductance.