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. 0.512. 0.443. 0.649. 0.573. 0.512. 0.443. 0.649. 0.573. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines When operating, two or more transformers in parallel, % impedance of these transformers should be inversely proportional to MVA rating of transformers. such that actual impedance of all transformers would be same. proportionate to MVA rating of transformers. same. inversely proportional to MVA rating of transformers. such that actual impedance of all transformers would be same. proportionate to MVA rating of transformers. same. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Scott connections are used for single phase to three phase transformation. three phase to single phase transformation. three phase to two phase transformation. any of the above. single phase to three phase transformation. three phase to single phase transformation. three phase to two phase transformation. any of the above. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In a seperately excited DC Motor if field current is increased, it will Increase acceleration duration. Reduce armature heating. Reduce starting torque. Increase speed Increase acceleration duration. Reduce armature heating. Reduce starting torque. Increase speed 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, 3 , 5 1, 3, 5 2, 4 ,5 1, 4 2, 3 , 5 1, 3, 5 2, 4 ,5 1, 4 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Slip speed is the difference of synchronous speed and actual rotor speed. half of the sum of synchronous and rotor speeds. sum of synchronous and rotor speeds. difference of actual rotor speed and synchronous speed. difference of synchronous speed and actual rotor speed. half of the sum of synchronous and rotor speeds. sum of synchronous and rotor speeds. difference of actual rotor speed and synchronous speed. ANSWER DOWNLOAD EXAMIANS APP
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