Electrical Machines A commutator with a diameter of 50 cm rotating at 1000 rpm. For a brush width of 1.5 cm, find the time of commutation in ms. 0.443. 0.649. 0.512. 0.573. 0.443. 0.649. 0.512. 0.573. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A 240 V DC series motor takes 40 A when giving its rated output at 1500 rpm. Its resistance is 0.3 ohms. The value of resistance which must be added to obtain rated torque at 1000 rpm is 1.9 ohms. 5.7 ohms. 2.2 ohms. 6 ohms. 1.9 ohms. 5.7 ohms. 2.2 ohms. 6 ohms. ANSWER DOWNLOAD EXAMIANS APP
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 unchanged Eb is unchanged, but Td is zero Eb is zero, but Td is unchanged both Eb and Td are zero both Eb and Td are unchanged Eb is unchanged, but Td is zero Eb is zero, but Td is unchanged both Eb and Td are zero ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines For which of the following loads, armature reaction is magnetizing in nature? pure inductive load None of these pure capacitive load pure resistive load pure inductive load None of these pure capacitive load pure resistive load ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines If starting current of a 3 - Φ induction motor is 5 times the rated current, while rated slip is 4 %, then ratio of starting torque to full load torque is 0.8. 1. 0.6. 0.4. 0.8. 1. 0.6. 0.4. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines An electric motor with constant output power will have a torque speed characteristics in the form of a Rectangular hyperbola Straight line parallel to the speed axis. Circle about the origin. Straight line through the origin. Rectangular hyperbola Straight line parallel to the speed axis. Circle about the origin. Straight line through the origin. ANSWER DOWNLOAD EXAMIANS APP
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