From the dc magnetization curve of figure it is possible to From the dc magnetization curve of figure it is possible to calculate the relative permeability Âľr = Bc/(Âľ0Hc) for M-5 electrical steel as a function of the flux level Bc. Assuming the core of figure to be made of M-5 electrical steel with the […]
It is desired to achieve a time-varying magnetic flux density It is desired to achieve a time-varying magnetic flux density in the air gap of the magnetic circuit of figure of the form Bg = B0 + B1 sin wt where B0 = 0.5 T and Bl = 0.25 T. The dc field B0 is […]
Loss data for the motor of Problem 5.10 are as follows: Loss data for the motor of Problem 5.10 are as follows: Open-circuit core loss at 4160 V = 37 kW. Friction and windage loss = 46 kW. Field-winding resistance at 75째C = 0.279?. Compute the output power and efficiency when the motor is operating […]
Linear induction motors have been proposed for a variety of Linear induction motors have been proposed for a variety of applications including high-speed ground transportation. A linear motor based on the induction-motor principle consists of a car riding on a track. The track is a developed squirrel-cage winding, and the car, which is 4.5 m […]
Small single-phase permanent-magnet ac generators are frequently Small single-phase permanent-magnet ac generators are frequently used to generate the power for lights on bicycles. For this application, these generators are typically designed with a significant amount of leakage inductance in their armature winding. A simple model for these generators is an ac voltage source ea(t) = […]
The constant-speed magnetization curve for a 25-kW, 250-V dc The constant-speed magnetization curve for a 25-kW, 250-V dc machine at a speed of 1200 r/min is shown in Figure. This machine is separately excited and has an armature resistance of 0.14O. This machine is to be operated as a dc generator while driven from a […]
A square voltage wave having a fundamental frequency of 60 A square voltage wave having a fundamental frequency of 60 Hz and equal positive and negative half cycles of amplitude E is applied to a 1000-turn winding surrounding a closed iron core of 1.25 x 10â3 m2 cross section. Neglect both the winding resistance and […]
The 145 MW hydroelectric generator of Problem 5.15 is operating The generator of Problem 5.22 achieves rated open-circuit armature voltage at a field curren A synchronous machine with a synchronous reactance of 1.28 per unit is operating as a generator at a real power loading of 0.6 per unit connected to a system with a […]
The 145 MW hydroelectric generator of Problem 5.15 is operating The generator of Problem 5.22 achieves rated open-circuit armature voltage at a field current of 850 A. It is operating on the system of Problem 5.22 with its voltage regulator set to maintain the terminal voltage at 0.99 per unit (23.8 kV). a. Use MATLAB […]
A three-phase induction motor, operating at rated voltage and A three-phase induction motor, operating at rated voltage and frequency, has a starting torque of 135 percent and a maximum torque of 220 percent, both with respect to its rated-load torque. Neglecting the effects of stator resistance and rotational losses and assuming constant rotor resistance, determine: […]