Electrical Machines A generator may loose residual magnetism due to vibrations. heating. over excitation. any of these. vibrations. heating. over excitation. any of these. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines For a 3-phase, 4 pole, 50 Hz synchronous motor the frequency, pole number and the frequency are halved. The motor speed will be 1500 rpm 75 rpm 3000 rpm 375 rpm 1500 rpm 75 rpm 3000 rpm 375 rpm ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The armature core of a DC machine is laminated to minimise hysteresis loss temperature rise mechanical loss eddy-current loss hysteresis loss temperature rise mechanical loss eddy-current loss ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The direction of rotation of a DC motor can be determined by Fleming's right hand rule. Fleming's left hand rule. Ampere's law. Lenz's law. Fleming's right hand rule. Fleming's left hand rule. Ampere's law. Lenz's law. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines An IM cannot run at synchronous speed because air friction will prevent it. none of above. rotor torque will not be produced. induction motor will become synchronous motor. air friction will prevent it. none of above. rotor torque will not be produced. induction motor will become synchronous motor. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines φA 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 speed when running as a motor taking 40 A at 250 V. Armature reaction weakens the field by 4%. 970 RPM 960 RPM 920 RPM 940 RPM 970 RPM 960 RPM 920 RPM 940 RPM ANSWER DOWNLOAD EXAMIANS APP
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