Electrical Machines A 240 V dc series motor takes 40 A when giving its rated output at 1500 rpm. Its resistance is 0.3 Ω. The value of resistance which must be added to obtain rated torque at 1000 rpm is 6 Ω 1.9 Ω 2.2 Ω 5.7 Ω 6 Ω 1.9 Ω 2.2 Ω 5.7 Ω ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A 250 volt dc series motor having an armature resistance of 0.2 Ω takes a load current of 60 A. What will be the torque produced at the shaft of the motor? Consider brush drop of 1V. can not be determined. 266.20 N-m. 133.22 N-m 234.76 N-m. can not be determined. 266.20 N-m. 133.22 N-m 234.76 N-m. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A DC generator beyond critical resistance will generate maximum voltage. maximum power. maximum current. no voltage. maximum voltage. maximum power. maximum current. no voltage. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines How can the synchronous speed of a 3 - Φ IM be varied? By varying the supply frequency. Both (A) and (B). By varying number of poles. By varying supply voltage. By varying the supply frequency. Both (A) and (B). By varying number of poles. By varying supply voltage. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The factors that are responsible for decrease in terminal voltage of a shunt generator are armature resistance, effect of armature reaction. reduction in field current, effect of armature reaction, armature. armature resistance, effect of armature reaction. armature resistance, inter poles, armature. armature resistance, effect of armature reaction. reduction in field current, effect of armature reaction, armature. armature resistance, effect of armature reaction. armature resistance, inter poles, armature. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A DC shunt machine generates 250 V on open circuit at 1000 RPM. Armature resistance is 0.5 Ω, field resistance 250 Ω. When running as a motor takes 4 A at 250 V. Calculate the efficiency when running as a motor taking 40 A at 250 V. Armature reaction weakens the field by 4%. 67.5% 82.5% 72.5% 78.5% 67.5% 82.5% 72.5% 78.5% ANSWER DOWNLOAD EXAMIANS APP
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