"A motor is used to drive a hoist. Motor characteristics are given by: [Quadrants I,II,IV: N= -8.2T+2031 , RPM // Quadrants II,III,IV; N= -8.2T-2031 , RPM ] when hoist is loaded TL= 188 , Nm and when it is empty TL= -72 , Nm Calculate the equilibrium speeds for operation in all four quadrants. . Choose Only one answer " II

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

× 4:03 K s.eng.ruh.ac.lk □ 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…