Electrical Machines The direction of rotation of a DC motor can be determent by Lenzs law. Flemings left hand rule. Amperes law. Flemings right hand rule. Lenzs law. Flemings left hand rule. Amperes law. Flemings right hand rule. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In V/f speed control of 3-phase induction motor, with increase in frequency, the slip at which maximum torque occurs increase. None of these decrease. either of these. increase. None of these decrease. either of these. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The armature shaft must be able to withstand any unbalanced magnetic pull on the armature core. twisting strains due to transmission of torque. bending moment due to weight of the armature. All of these any unbalanced magnetic pull on the armature core. twisting strains due to transmission of torque. bending moment due to weight of the armature. All of these ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A synchronous generator is feeding a zero power factor (lagging) load at rated current. The armature reaction is cross – magnetizing. magnetizing. demagnetizing. ineffective. cross – magnetizing. magnetizing. demagnetizing. ineffective. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines At slip s = 1 torque developed in machine is starting torque. none. electromagnetic torque. maximum torque. starting torque. none. electromagnetic torque. maximum torque. 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%. 920 RPM 960 RPM 970 RPM 940 RPM 920 RPM 960 RPM 970 RPM 940 RPM ANSWER DOWNLOAD EXAMIANS APP
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