A PWM inverter such as that of Figure is operating from a A PWM inverter such as that of Figure is operating from a dc voltage of 75 V and driving a load with L = 53 mH and R = 1.7O. For a switching frequency of 1500 Hz, calculate the average load current, the […]
Consider a 460-V, 25-kW, four-pole, 60-Hz induction motor which Consider a 460-V, 25-kW, four-pole, 60-Hz induction motor which 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 motor is to be operated from a variable […]
Consider a three-phase 6/8 VRM. Consider a three-phase 6/8 VRM. The stator phases are excited sequentially, requiting a total time of 15 msec. Find the angular velocity of the rotor in r/min.
Consider a three-phase 6/8 VRM. The stator phases are excited Consider a three-phase 6/8 VRM. The stator phases are excited sequentially, requiting a total time of 15 msec. Find the angular velocity of the rotor in r/min.
Consider a multi-stack, multiphase variable-reluctance stepping Consider a multi-stack, multiphase variable-reluctance stepping motor, such as that shown schematically in Figure, with 14 poles on each of the rotor and stator stacks and three stacks with one phase winding per stack. The motor is built such that the stator poles of each stack are aligned. a. […]
Consider a dc shunt motor connected to a constant-voltage source Consider a dc shunt motor connected to a constant-voltage source and driving a load requiring constant electromagnetic torque. Show that if Ea > 0.5Vt (the normal situation), increasing the resultant air-gap flux decreases the speed, whereas if Ea < 0.5vt=”” (as=”” might=”” be=”” brought=”” about=”” […]
Assume the total load in the system of Problem 2.26 Assume the total load in the system of Problem 2.26 to remain constant at 325 MVA. Write a MATLAB script to plot the line-to-line voltage which must be applied to the sending end of the feeder to maintain the load voltage at 24 kV line-to-lines […]
A loudspeaker is made of a magnetic core of infinite A loudspeaker is made of a magnetic core of infinite permeability and circular symmetry, as shown in figures a and b. The air-gap length g is much less than the radius r0 of the central core. The voice coil is constrained to move only in […]
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 […]