Electrical Machines The frequency of voltage generated by an alternator having 8 poles and rotating at 250 rpm is 50 Hz. 25 Hz. 60 Hz. 16.67 Hz. 50 Hz. 25 Hz. 60 Hz. 16.67 Hz. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The mechanical power is developed by a DC motor is maximum when back emf is equal to applied voltage. none of above. back emf is equal to twice of applied voltage. back emf is equal to half of applied voltage. back emf is equal to applied voltage. none of above. back emf is equal to twice of applied voltage. back emf is equal to half of applied voltage. 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. 133.22 N-m 234.76 N-m. 266.20 N-m. can not be determined. 133.22 N-m 234.76 N-m. 266.20 N-m. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Minimum allowable resistivity of power transformer insulating oil is generally taken as 1 X 1012 Ω - cm at 27°C and 0.1 X 1012 3 X 1012 Ω - cm at 27°C and 0.3 X 1012 2 X 1012 Ω - cm at 27°C and 0.2 X 1012 4 X 1012 Ω - cm at 27°C and 0.4 X 1012 1 X 1012 Ω - cm at 27°C and 0.1 X 1012 3 X 1012 Ω - cm at 27°C and 0.3 X 1012 2 X 1012 Ω - cm at 27°C and 0.2 X 1012 4 X 1012 Ω - cm at 27°C and 0.4 X 1012 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Example of double excited machine is DC Shunt Motor Both are correct. Synchronous motor. None of these DC Shunt Motor Both are correct. Synchronous motor. None of these ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The rotor speed of an induction motor is given by 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 Nr = 120f / p × (1-s). Ns = 120f /p × ( 1 - r). ANSWER DOWNLOAD EXAMIANS APP
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