Electrical Machines Considering a galvanometer is connected to the rotor of a 3 - Φ, 4 pole, 50 Hz IM and is making 130 oscillations in a minute, then calculate the rotor speed? 1435. 1450. 1440. 1500. 1435. 1450. 1440. 1500. 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 1, 4 2, 3 , 5 1, 3, 5 2, 4 ,5 1, 4 2, 3 , 5 1, 3, 5 2, 4 ,5 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A 200 V DC machine supplies 20 A at 200 V as a generator. The armature resistance is 0.2 Ω. If the machine is now operated as a motor at same terminal voltage and current but with the flux increased by 10%, the ratio of motor speed to generator speed is 0.95 0.87 1.06 0.96 0.95 0.87 1.06 0.96 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A dc shunt motor runs at a no-load speed of 1140 rpm. At full load, armature reaction weakens the main flux by 5% whereas the armature circuit voltage drops by 10%. The motor full-load speed in rpm is 1203 1080 1000 1200 1203 1080 1000 1200 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In most condition which frame of motor will be preferred? Totally enclosed fan coiled. Drip proof. Splash proof. Open type. Totally enclosed fan coiled. Drip proof. Splash proof. Open type. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In the 3-phase induction motor, the resultant flux is of a constant nature and is 3/2 times maximum value of flux due to any phase equal to φm, where φm is the maximum flux due to any phase 1/2 times maximum value of flux due to any phase 3 times maximum value of flux due to any phase 3/2 times maximum value of flux due to any phase equal to φm, where φm is the maximum flux due to any phase 1/2 times maximum value of flux due to any phase 3 times maximum value of flux due to any phase ANSWER DOWNLOAD EXAMIANS APP
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