If the synchronizing power coefficient and the change in the rotor angle is given by 1.2 p.u and 0.89 p.u respectively, the change in power is given by . the power angle curve. in 0.0186 1.068 O 1.199 0.741

a 6 A single phase 400W, 50 Hz Motor takes Suply current of SOA at power factor of 0. Lagging The motor power factor hall been Improved to 0.9 lagging by connecting a capacitor in parallet. Calculeite the size of capacitor

• - 1800 pm In a two pole 3-p synchronous generator, the peak flux of rotor magnetic field is o5Tand the rotor rate of rotation is 1800 rpm. The stator windings have a surface area of 0.1 m? and there are 50 turns per Bmax : 0.5T, 0.5T coil. The machine is A-connected. A: 0-1 m? N: 50 a) What is the RMS phase and line voltage of the generator? b) Write the three stator phase voltages as functions of time.

Which of the following statements related to wind turbine types are true? Select one or more: a. The Savonius rotor will not start without an auxiliary motor b. In modern industrial-sized wind turbines, the most common type of turbine is a 3-bladed wind turbine. c. In a downwind turbine, the blades are on the (upper) side of the wind when viewed from the nacell

a) To increase the output of an ac generator, a student has the choice of doubling either the generator's magnetic field or its frequency. To maximize the increse in emf output, A - he should double the magentic field.B - he should double the frequency.C - it does not matter which one he doubles. b) Two students display their ac generators at a science fair. The generator made by Student A has a loop area of 100 cm22 rotating in a magnetic field of 20 mT at at 60 Hz. The generator made by Student B has a loop area of 75 cm22 rotating in a magnetic field of 200 mT at at 120 Hz. Calculate the emf of the two generators. Student A: Student B:

In a synchronous generator, a DC current is applied to the rotor windingList two advantages of this arrangement.

The speed of an alternator rotor in rpm that has 6 poles and is producing a voltage at 57.4 Hertz is

×ばつ 4:03 K s.eng.ruh.ac.lk □しろいしかく Û 8. Figure 4 shows the core of a simple dc motor. The magnetization curve for the metal in this core is given by Figure 5 and Figure 6. Assume that the cross-sectional area of each air gap is 18 cm2 and that the width of each air gap is 0.05 cm. The effective diameter of the rotor core is 4 cm. L It is desired to build a machine with as great a flux density as possible while avoiding excessive saturation in the core. What would be a reasonable maximum flux density for this core? ii. What would be the total flux in the core at the flux density of part (i)? iii. The maximum possible field current for this machine is I A. Select a reasonable number of turns of wire to provide the desired flux density while not exceeding the maximum available current. Flux Density, B (T) 2.8 སྤྲ ཤཱ ཀ ཀཱ བྷ ཀ ཡཱཾ བ ་ 1.2 1.0 0.4 0.2 4-48cm Figure 4 0 10 20 30 40 50 100 → Depth 4 cm -0.05 cm 200 300 500 1000 2000 Magnetizing Intensity, H (A.turns/m) Figure 5 Magnetization curve...