Consider a two-phase stepper motor with a permanent-magnet rotor Consider a two-phase stepper motor with a permanent-magnet rotor such as shown in Figure and whose torque-angle curve is as shown in Figure a. This machine is to be excited by a four-bit digital sequence corresponding to the following winding excitation: a. Make a table of […]
The nameplate on a 50-MVA, 60-Hz single-phase transformer The nameplate on a 50-MVA, 60-Hz single-phase transformer indicates that it has a voltage rating of 8.0-kV: 78-kV. An open-circuit test is conducted from the low-voltage side, and the corresponding instrument readings are 8.0kV, 62.1A, and 206kW. Similarly, a short-circuit test from the low-voltage side gives readings […]
Consider the case in which the load on the synchronous Consider the case in which the load on the synchronous motor in the field oriented torque-control system of Problem 11.13 is increased, and the motor begins to slow down. Based upon some knowledge of the load characteristic, it is determined that it will be necessary […]
The motor of Problem 5.5 is supplied from a 460-V, three-phase The motor of Problem 5.5 is supplied from a 460-V, three-phase source through a feeder whose impedance is Zf = 0.084 + j0.82?. Assuming the system (as measured at the source) to be operating at an input power of 40 kW, calculate the magnitude […]
The magnetic circuit of Problem 1.1 has a nonlinear core The magnetic circuit of Problem 1.1 has a nonlinear core material whose permeability as a function of Bm is given by where Bm is the material flux density. a. Using MATLAB, plot a dc magnetization curve for this material (Bm vs. Hm) over the range […]
The magnetic circuit of figure has two windings and two The magnetic circuit of figure has two windings and two air gaps. The core can be assumed to be of infinite permeability. The core dimensions are indicated in the figure. a. Assuming coil 1 to be carrying a current Il and the current in coil […]
The manufacturer’s data sheet for a 26-kV, 750-MVA 60-Hz three-p The manufacturer’s data sheet for a 26-kV, 750-MVA 60-Hz three-phase synchronous generator indicates that it has a synchronous reactance Xs = 2.04 and a leakage reactance Xal = 0.18, both in per unit on the generator base. Calculate (a) The synchronous inductance in mH, (b) […]
The linear-motor armature of Problem 4.25 has a total active The linear-motor armature of Problem 4.25 has a total active length of 7 wavelengths, with a total of 280 turns per phase with a winding factor kw = 0.91. For an air-gap length of 0.93 cm, calculate the rms magnitude of the balanced three-phase currents […]
The inductor of Problem 1.13 is to be operated fro The inductor of Problem 1.13 is to be operated from a 60-Hz voltage source. (a) Assuming negligible coil resistance, calculate the rms inductor voltage corresponding to a peak core flux density of 1.5 T. (b) Under this operating condition, calculate the rms current and the […]
The magnetic circuit of figure and Problem 1.6 has the The magnetic circuit of figure and Problem 1.6 has the following dimensions: Ac = 8.2cm2 lc = 23cm lp = 2.8 cm g = 0.8 mm X0 = 2.5 cm N = 430 turns a. Assuming a constant permeability of Âľ = 2800Âľ0, calculate the […]