4.B] When three-phase balanced impedances are connected in star, across a three-phase, 415V, 50Hz supply, the line current drawn is 20A, at a lagging p.f of 0.4. Determine the parameters…
6. B] With usual notations, develop the torque equation of the D.C motor. Answer: The turning or twisting force about an axis is called torque.Consider a wheel of radius R…
3.B] A circuit consists of a resistance of 20Ω, an inductance of 0.05H connected in series. A supply of 230V at 50 Hz is applied across the circuit. Determine the…
8. B] Develop the E.M.F. equation of synchronous generator. Answer: Let φ = Flux per pole, in WbP = Number of polesN = Synchronous speed in r.p.m.f = Frequency of…
8. A] With neat sketches, explain the construction of two types of synchronous generators. Answer: There are two types of generators:i) Salient pole of generatorii) Non Salient pole generators CONSTRUCTION:…
6. A] Discuss various types of losses in a transformer. Answer: The transformer has two types of losses :• Core or Iron losses [constant losses]• Copper losses [cu losses] Iron…
Problems on three phase synchronous generator 8.C] A 12 pole, 500 rpm star-connected alternator has 48 slots with 15 conductors per slot. The flux per pole is 0.02 Wb and…
Problems on 3 phase induction motor 7.C] A 12 pole 3 phase alternator is coupled to an engine running at 500 rpm. It supplies an induction motor that has a…
Problems on transformers 6.C] A 250 KVA, 11000/415 volts, 50 Hz single phase transformer has 80 turns on the secondary. Calculate i) Rated primary and secondary currents ii) Number of…
5.C] A 4 pole, 1500 r.p.m. D.C. generator has a lap wound armature, having 32 slots and 8 conductors per slot. If the flux per pole is 0.04Wb, determine the…
