Electrical Machines To increase starting torque of a 3-phase slip ring induction motor, preferred method is to increase rotor resistance supply frequency supply voltage None of these rotor resistance supply frequency supply voltage None of these ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A 240 V, dc shunt motor draws 15 A while supplying the rated load at a speed of 80 rad/s. The armature resistance is 0.5 W and the field winding resistance is 80 W. The external resistance to be added in the armature circuit to limit the armature current to 125% of its rated value is 31.9 Ω 31.1 Ω 15.1 Ω 15.9 Ω 31.9 Ω 31.1 Ω 15.1 Ω 15.9 Ω ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The rotor speed of an induction motor is given by Nr = 120f / p × (1-s). Ns = 120f /p × ( 1 - r). Ns = 120f / p × ( 1 - s ). None of these Nr = 120f / p × (1-s). Ns = 120f /p × ( 1 - r). Ns = 120f / p × ( 1 - s ). None of these ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines If s is the slip and f is the supply frequency of an induction motor, the frequency of rotor current is given by s2. f / s. sf. sf / 2. s2. f / s. sf. sf / 2. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In a DC compound motor the field regulator is provided to control the field flux. demagnetize the field partially. limit the armature current. control the armature flux. control the field flux. demagnetize the field partially. limit the armature current. control the armature flux. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In induction motor the 7th harmonic torque may make the motor rotate at (1 / 7)th synchronous speed. This is called cogging. crawling. resonance. harmonics. cogging. crawling. resonance. harmonics. ANSWER DOWNLOAD EXAMIANS APP
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