مشاهدة النسخة كاملة : Electrical Machines Equation


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03-03-2013, 05:11 PM
Electrical Machines Equation
السلام عليكم ورحمة الله وبركاتة
هذي معادلات اخذته من الجامعه والمسطلحات الانجليزيه خبلت راسي:86: الي با الاحمر ارجو مساعدتي في هادا
وجزاكم الله خير..


A four-pole wave-connected armature has 51 slots with 12 conductors per slot and is driven at 900 RPM. if the useful flux per pole is 25 mWb,calculate the value of the generated EMF





A d.c motor takes an armature current of 110A at 480 V.The resistance of the armature circuit is 0.2 ohm.The machine has six poles and the armature is lap-connected with 864 conductors. The flux per pole is 0.05 Wb.
calculate a) the speed
b) the gross torque developed by the armature




The torque required to driven a d.c. generator at 15 rev/sec is 2 kNm. The core, friction, and windage losses in the machine are 8 KW. calculate the power generated in the armature winding





A ****** motor runs at 600 RPM when taking 110 A from a 230-V supply. The resistance of the armature circuit is 0.12 ohm and that of the ****** winding is 0.03 ohm. calculate the speed when the current has fallen to 50A, assuming the
useful flux per pole of 110 A to be 0.024Wb and that for 50 A to be 0.00155Wb






A shunt generator is to be converted into a level-compounded generator by the addition of a ****** field winding. From a test on the machine with shunt excitation (field) only, it is found that the shunt current is 4.1 A to give 440 V ** ** load and 5.8 A to give the same voltage when the machine is supplying its full load of 200 A. The shunt winding has 1200 turns per pole. Find the number of ****** turns required per pole






A 100-kW, 460-V shunt generator was run as a motor on ** load at its rated voltage and speed. The total current taken was 9.8 A, including a shunt current of 2.7 A .The resistance of the armature circuit at **rmal working temperature was 0.11 ohm . Calculate the efficiency at full load.



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