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Figure shows the general nature of the slot-leakage flux produce Figure shows the general nature of the slot-leakage flux produced by current i in a rectangular conductor embedded in a rectangular slot in iron. Assume that the iron reluctance is negligible and that the slot leakage flux goes straight across the slot in the region […]

For the potential transformer of Problem 2.29, find the maximum For the potential transformer of Problem 2.29, find the maximum reactive burden (minimum reactance) which can be applied at the secondary terminals such that the voltage magnitude error does not exceed 0.5 percent. Is this the question you were looking for? If so, place your […]

For each of the following changes in operating condition for For each of the following changes in operating condition for a dc shunt motor, describe how the armature current and speed will vary: a. Halving the armature terminal voltage while the field fluxes and load torque remain constant. b. Halving the armature terminal voltage while […]

For a 25-kW, 230-V, three-phase, 60-Hz squirrel-cage motor opera For a 25-kW, 230-V, three-phase, 60-Hz squirrel-cage motor operating at rated voltage and frequency, the rotor I2R loss at maximum torque is 9.0 times that at full-load torque, and the slip at full-load torque is 0.023. Stator resistance and rotational losses may be neglected and the […]

A superconducting magnet has an inductance of 4.9 H, A superconducting magnet has an inductance of 4.9 H, a resistance of 3.6 mO, and a rated operating current of 80 A. It will be supplied from a 15-V rms, three-phase source through a three phase, phase-controlled bridge. It is desired to “charge” the magnet at […]

Figure shows the magnetic circuit for a permanent-magnet Figure shows the magnetic circuit for a permanent-magnet loudspeaker. The voice coil (not shown) is in the form of a circular cylindrical coil which fits in the air gap. A samarium-cobalt magnet is used to create the air-gap dc magnetic field which interacts with the voice coil […]

Figure shows a system consisting of a three-phase wound-rotor Figure shows a system consisting of a three-phase wound-rotor induction machine whose shaft is rigidly coupled to the shaft of a three-phase synchronous motor. The terminals of the three-phase rotor winding of the induction machine are brought out to slip rings as shown. With the system […]

Superconducting synchronous machines are designed with supercond Superconducting synchronous machines are designed with superconducting fields windings which can support large current densities and create large magnetic flux densities. Since typical operating magnetic flux densities exceed the saturation flux densities of iron, these machines are typically designed without iron in the magnetic circuit; as a result, […]

Thermal considerations limit the field-current of the Thermal considerations limit the field-current of the laboratory-size synchronous generator of Problem 4.18 to a maximum value of 2.4 A. If the peak fundamental air-gap flux density is limited to a maximum of 1.3 T, calculate the maximum torque (N 路 m) and power (kW) which can be […]

An inductor is made up of a 525-turn coil on An inductor is made up of a 525-turn coil on a core of 14-cm2 cross-sectional area and gap length 0.16 mm. The coil is connected directly to a 120-V 60-Hz voltage source. Neglect the coil resistance and leakage inductance. Assuming the coil reluctance to be […]