Question A.2 a) A marine slow-speed D.C. generator has an armature of diameter 3.0m and active conductors of length 510m

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Question A 2 A A Marine Slow Speed D C Generator Has An Armature Of Diameter 3 0m And Active Conductors Of Length 510m 1 (123.01 KiB) Viewed 28 times

Question A.2 a) A marine slow-speed D.C. generator has an armature of diameter 3.0m and active conductors of length 510mm. The average strength of the field in the air gap is 0.8T and the armature speed is 200 rev/min. If the armature has 144 conductors arranged in 8 parallel paths, find the e.m.f. generated at the machine terminals (1 decimal place). (5 marks) b) The D.C. generator in part (a) is now connected to two long straight parallel bus bars which have their centres 25mm apart. If each bar carries a load current of 120 A, calculate the mutual force/metre that the bus bars run (2 decimal place). [5 marks] c) A 230V D.C. shunt motor is now connected to the bus bars to drive a Freshwater pump. The motor has an input of 5kW when loaded. The armature and field resistances are 0.10 and 100 respectively. Calculate the back e.m.f.value 1 (1 decimal place). [5 marks) d) A coil consumes 300W when connected into a 60V D.C. circuit. When connected to an A.C Circuit of 130v, it consumes 1200W. What is the coil's reactance. (1 significant figure)? (5 marks] e) A single-phase AC motor has an input of 50.6A at 240V, the power input being 10kW and the output 9kW. Calculate the value of the apparent power (1 decimal place), power factor (2 decimal place) and the efficiency of the machine. [5 marks)