GATE EE 2018 EXAM:Electrical Machines Quiz 6

The air-gap between the yoke and armature in a dc motor is kept small

In a d.c. compound generator, "flat-compound" characteristic, required for certain applications, may be obtained by connecting a variable resistance;

A dc shunt generator is supplying a load of 1.8 kW at 200 V. Irs armature and field resistances are 0.4Ω and 200 Ω respectively. What is the generated emf?

The full-load copper loss and iron loss of a transformer are 6400 W and 5000 W, respectively. What are the above copper loss and iron loss, respectively at half-load?

An eight pole d.c. generator has a simple wave wound armature containing 32 coils of 6 turns each. Its flux per pole is 0.06 Wb. The machine is running at 250 rpm. The induced armature voltage is

A 5 kW, 200 V dc shunt motor has armature resistance of 1 ohm and shunt field resistance of 100 ohm. At no load, the motor draws 6 A from 200 V supply and runs at 1000 rpm. What is the total copper loss of the machine?

A 400V D.C. shunt motor takes 5A at no-load. R_a = 0.5 ohms, R_i = 200 ohms. What is the ratio of speed from full load to no-load, when the D.C. shunt motor lakes 50 A on full load?