Electrical Machines In DC generators, the brushes remain in contact with conductors which lie under north pole. lie under south pole. lie in the inter polar gaps. there is no hard and fast rule for this. lie under north pole. lie under south pole. lie in the inter polar gaps. there is no hard and fast rule for this. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A 3- phase synchronous motor can operate over a wide range of power factors i.e. from lagging to leading power factor. This is achieved by varying the speed. varying the applied voltage. changing the load. changing the field excitation. varying the speed. varying the applied voltage. changing the load. changing the field excitation. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The volt-ampere euation for a long-shunt compound motor is given by Vt= Ea– Iara Vt= Ea + Iara Vt = Ea + Iara+ ILrs Vt = Ea + Ia(ra + rs) Vt= Ea– Iara Vt= Ea + Iara Vt = Ea + Iara+ ILrs Vt = Ea + Ia(ra + rs) ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Which of following methods are suitable for the speed control of squirrel cage induction motor? 1. Voltage control. 2. Frequency control. 3. Pole changing method. 4. Rotor resistance control select the correct answer using the codes given below:- 1, 3 and 4. 2 and 4. 2, 3 and 4. 1, 2 and 3. 1, 3 and 4. 2 and 4. 2, 3 and 4. 1, 2 and 3. 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 1, 3, 5 2, 3 , 5 1, 4 2, 4 ,5 1, 3, 5 2, 3 , 5 1, 4 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Maximum allowable tan - delta (tanδ) of dielectric dispassion factor of power transformer insulating oil is generally taken as 1 at 90°C. 0.5 at 90°C. 3 at 90°C. 2 at 90°C. 1 at 90°C. 0.5 at 90°C. 3 at 90°C. 2 at 90°C. ANSWER DOWNLOAD EXAMIANS APP
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