1:52 PM | 5.7KB/s.. < EXAM.pdf File Preview HOD. 江苏科技大学课程考试卷(A) JUST COURSE EXAMINATION NAME: «Electrical Machinery>> Se

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1:52 PM | 5.7KB/s.. < EXAM.pdf File Preview HOD. 江苏科技大学课程考试卷(A) JUST COURSE EXAMINATION NAME: «Electrical Machinery>> Semester: 2021-2022 Spring Apartment Major Student II Name ITEM Part I Part II Part III TOTAL Marks TIVE 9:00 AM - 11:00 AM MARKS: First part is 15. second part is 45, and last part is 40. The total marks for this examination is 100. PART 1. Magnetic circuits problems (Total 15 points) 1. A ferromagnetic core is shown in Figure. The mean path length is 40 cm, and the cross- sectional area of the core is 12 cm². The winding on the left leg of the core has 400 turns. The current direction is shown in the figure. What flux would be produced by current -0.25 A? What about /=0.85 A? Draw the flux with direction in the figure. * Assume μ-4000 and constant. (par-4xx107) (5 points) 第1頁 共8 頁 2. A core with three legs is shown in Figure. Its depth is 5 cm, and there are 200 turns on the leftmost leg. The relative permeability of the core can be assumed to be 1500 and constant. What flux exists in each of the three legs of the core? What is the flux density in each of the legs? Assume a 5% increase in the effective area of the air gap due to fringing effects. (ar4x10) (10 points) -3- +0+ Mar 1900 f 9 features... Use the following document Full Screen Mark/Fill Use Now > Conv... 注意,装订线外,例写答案 35% ... BO