Electrical Machines Sparkless commutation can be achieved by employing inter poles. high resistance carbon brushes. compensating winding. any one or more of the above methods. inter poles. high resistance carbon brushes. compensating winding. any one or more of the above methods. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In shunt dc motor the direction of rotation of the motor will reversed. When only armature terminals are reversed. none of above. either field terminals are reversed or armature terminals are reversed. only field terminals are changed. only armature terminals are reversed. none of above. either field terminals are reversed or armature terminals are reversed. only field terminals are changed. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The rotor speed of an induction motor is given by Nr = 120f / p × (1-s). Ns = 120f /p × ( 1 - r). Ns = 120f / p × ( 1 - s ). None of these Nr = 120f / p × (1-s). Ns = 120f /p × ( 1 - r). Ns = 120f / p × ( 1 - s ). None of these ANSWER DOWNLOAD EXAMIANS APP
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 ? 2, 3 and 4 1 and 4 3 and 5 1, 2 and 5 2, 3 and 4 1 and 4 3 and 5 1, 2 and 5 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines For satisfactory performance of 3-phase 480V, 60 Hz induction motor, the supply voltage at 50 Hz should be equal to 350 V. 420 V. 480 V. 400 V. 350 V. 420 V. 480 V. 400 V. 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
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