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Electric Machinery Fundamentals (Solutions Manual) Part 10

Tham khảo tài liệu 'electric machinery fundamentals (solutions manual) part 10', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | e IỊ4 I f cP nv g p mech core p straP Solution a Since this machine has 8 poles it rotates at a speed of 120f 120 50 Hz n -----------------1500 r min p 4 If the output power is 100 kW the output torque is I load 5 -----100 00 Wd 1 min 637 N m 1500 r min 1 r 60 s b The input power is p ouP 110 kW 100 kW _ IN I 0.91 c The mechanical speed is n 1500 r min d The armature current is . -- p 110 kW . I - ------- - ------- 15 A A L V3 Ỵ PF V3 480 V 0.85 ỊA 156 31. A Therefore EA is E VB Ị A A S R jX 277 0 v 0.08 1.0 156 31.8 A EA 156 31.8 A j EA 375 2 .8 V e The magnitude of the armature current is 375 A. f The power converted from electrical to mechanical form is given by the equation conv IN p p 2 CU 3 A p I 3 R 56 A 0.08 5.8 kW pv ỊN D pp 0 kW D 5.8 kW 104.2 kW g The mechanical core and stray losses are given by the equation mech corp p . p OUT D p 04.2 kW 100 kW 4.2 kW 6-12. The Y-connected synchronous motor whose nameplate is shown in Figure 6-21 has a per-unit synchronous reactance of 0.90 and a per-unit resistance of 0.02. a What is the rated input power of this motor b What is the magnitude of E A at rated conditions 164 c If the input power of this motor is 10 MW what is the maximum reactive power the motor can simultaneously supply Is it the armature current or the field current that limits the reactive power output d How much power does the field circuit consume at the rated conditions e What is the efficiency of this motor at full load f What is the output torque of the motor at the rated conditions Express the answer both in newtonmeters and in pound-feet. Solution The base quantities for this motor are V .base 6600 V 6600 V ì .base 43 3811V I .Ja e 04 A n jase rateS 3 T V 3 6600 V 1404 A 1.0 16.05 MW a The rated input power of this motor is IN Jị PVII 3 6600 V 1404 A 1.0 - 16.05 MW b At rated conditions 1.0 0 p V quantities as and I 1.0 0 p so EA is given in per-unit E VB I A A N R s jX 0.02 1.0 0 0.90 1 0 ea 1 0 j Ea 1.33 4 .6 pu The base phase voltage of .