Electrical Machines The brush-axis of a bipolar dc motor is rotated by 90°. The effect of this rotation on the back emf Eband the torque developed Tdwould be such that both Eb and Td are zero both Eb and Td are unchanged Eb is zero, but Td is unchanged Eb is unchanged, but Td is zero both Eb and Td are zero both Eb and Td are unchanged Eb is zero, but Td is unchanged Eb is unchanged, but Td is zero ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In the 3-phase induction motor, the resultant flux is of a constant nature and is 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 3/2 times maximum value of flux due to any phase equal to φm, where φm is the maximum flux due to any phase ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines With the increase in speed of a DC motor both back emf as well as line current increase. both back emf as well as line current fall. back emf falls and line current increases. back emf increases but line current falls. both back emf as well as line current increase. both back emf as well as line current fall. back emf falls and line current increases. back emf increases but line current falls. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In DC machine shape of armature MMF wave is? Peaky in nature. Triangular and directed towards brush axis. Saddle shape. Triangular and directed towards main pole. Peaky in nature. Triangular and directed towards brush axis. Saddle shape. Triangular and directed towards main pole. 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 ? 1, 2 and 5 1 and 4 3 and 5 2, 3 and 4 1, 2 and 5 1 and 4 3 and 5 2, 3 and 4 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Find the reactance voltage when current is changed from -2A to 2A in 4 sec and self inductance is 1H? 4 V 1 V 0 V 2 V 4 V 1 V 0 V 2 V ANSWER DOWNLOAD EXAMIANS APP
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