#4. ANSWER 4 AND 5 ONLY. NO ROUNDING OFF. STRICTLY HANDWRITTEN THEN BOX THE FINAL ANSWERS. RUSH PLS

Why is it necessary to conduct polarity tests on transformers?

Full solutions for the question with explanation

A 4 pole dc shunt generator with a shunt field resistance of 100 ohm and an armature resistance of 1 ohm has 378 wave connected conductor in its armature. the flux per pole is 0.02wb, if the load resistance of 10 ohm is connexted across the aemature terminal and the generator driven at 1000rpm, calculate the power obsorbed by load

T-a. The direction of rotation of a single-phase split-phase motor can be change by........ a) reversing the connection of the start winding b) reversing the connection of the run winding c) reversing the connection of the start and run winding at the same time d) "a" or "b", not "c" T-b. Single-phase split-phase motors using an electrolytic capacitor in the start winding circuit should not be cycled more than about__________ time per hour. a) 8 b) 12 c) 24 d) none of the above T-c. When replacing the capacitor in a capacitor-start induction-run motor, one must be sure to replace the bad capacitor with__________ . a) a smaller one b) one of the same size c) a larger one d) none of the above

C. Is full-pitch winding possible? Why?

. A 20 kW compound generator works on full load with terminal voltage of 250 V. The armature, series, and shunt windings have resistances of 0.05-ohm, 0.025 ohm, and 100 ohms, respectively. If the machine is connected short shunt, the emf generated is nearest to. (Our subject is Electrical Machines 1 ) (I need a clear answer and solution. Thank you so much)

Calculate the flux per pole required on full-load for a 50 kW, 400 V, 8-pole, 600 r.p.m. d.c. shunt generator with 256 conductors arranged in a lap-connected winding. The armature winding resistances is 0.1 Q, the shunt field resistance is 200 Q and there is a brush contact voltage drop of 1 V at each brush on full- [0.162 Wb] 5. load. Calculate the flux in a 4-pole dynamo with 722 armature conductors generating 500 V when running at 1000 r.p.m. when the armature is (a) lap connected (b) wave connected. [(a) 41.56 mWb (b) 20.78 mWb] (City & Guilds, London) 7. A 4-pole machine running at 1500 r.p.m. has an armature with 90 slots and 6 conductors per slot. The flux per pole is 10 mWb. Determine the terminal e.m.f. as d.c. Generator if the coils are lap-connected. If the current per conductor is 100 A, determine the electrical power. [810 V, 324 kW] (London Univ.) 8. An 8-pole lap-wound d.c. generator has 120 slots having 4 conductors per slot. If each conductor can carry 250 A and if…