Electrical Machines A delta/star transformer is connected in parallel to a star/delta transformer. The turn ratio former is x times latter, the x is √3 1/3 1/√3 3 √3 1/3 1/√3 3 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Field divertor method of speed control of a DC series motor gives speed above rated one due to reduction of Field current. Line current. None of above. Armature current. Field current. Line current. None of above. Armature current. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines An inverted V curve of synchronous motor shows variation of power factor and DC excitation at constant load. supply voltage and excitation current at constant load. supply voltage and field current at constant excitation. power factor and supply voltage during hunting. power factor and DC excitation at constant load. supply voltage and excitation current at constant load. supply voltage and field current at constant excitation. power factor and supply voltage during hunting. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A 3-phase, 50 Hz, 4 pole induction motor is running at 1440 rpm. Find the rotor efficiency? 92% 95% 96% 94% 92% 95% 96% 94% 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 2, 3 , 5 1, 4 1, 3, 5 2, 4 ,5 2, 3 , 5 1, 4 1, 3, 5 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines What is the necessity of copper brushes in a dc motors? To increase the flux cutting by the rotor. To convert alternating supply current to direct current. To absorb the mechanical shocks produced during running condition. None of these. To increase the flux cutting by the rotor. To convert alternating supply current to direct current. To absorb the mechanical shocks produced during running condition. None of these. ANSWER DOWNLOAD EXAMIANS APP
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