Electrical Machines Consider the following statements regarding the magnetization characteristics of a dc generator : 1. It represents the variation of field flux with field current. 2. Variation of open-circuit terminal voltage with field current is independent of speed 3. It is non-linear from zero to rated field current 4. It helps to determine the critical field resistance at a given speed 5. It always starts from the origin Which of these statements are correct ? 1 and 4 2, 3 and 4 1, 2 and 5 3 and 5 1 and 4 2, 3 and 4 1, 2 and 5 3 and 5 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A DC shunt generator builds up to a voltage of 220 V at no load while running at its rated speed. If the speed of the generator is raised by 25% kepping the circuit conditions unaltered, then the Voltage to which the machine would build up will increase to value lying between 220 V and 1.25 times 220 V not change and remain at 220 V increase to a value greater than 1.25 times 220 V increase to 1.25 times 220 V increase to value lying between 220 V and 1.25 times 220 V not change and remain at 220 V increase to a value greater than 1.25 times 220 V increase to 1.25 times 220 V ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The armature core of a DC machine is laminated to minimise mechanical loss hysteresis loss temperature rise eddy-current loss mechanical loss hysteresis loss temperature rise eddy-current loss ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The commutator segments of DC machines are made up of brass copper hard-drawn copper copper alloy brass copper hard-drawn copper copper alloy ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Consider the following statements regarding dc machines : 1. possible resistance of shunt-field winding is 1 Ω 2. possible resistance of series-field winding is 1 Ω 3. electrographite brushes are used for 230 V, 10 A machines 4. Copper-graphite brushes are used for 230 V, 10 A machines 5. Possible armature-circuit resistance is 1 Ω From these, the correct statements are 2, 4 ,5 2, 3 , 5 1, 4 1, 3, 5 2, 4 ,5 2, 3 , 5 1, 4 1, 3, 5 ANSWER DOWNLOAD EXAMIANS APP