Electrical Machines In an induction motor, what is the ratio of rotor input to rotor copper loss? S 1/(1-S) 1/S 1-S S 1/(1-S) 1/S 1-S ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In a synchronous machine, if φ is the flux per pole and f is the frequency of the emf induced E then E ∝ f/φ E ∝ φ/f E ∝ φf E ∝ 1/(φf) E ∝ f/φ E ∝ φ/f E ∝ φf E ∝ 1/(φf) ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In an induction motor, air gap power is 10 Kw and mechanically developed power is 8 Kw. What are the rotor ohmic losses? 0.5Kw 2KW 3KW 1.5KW 0.5Kw 2KW 3KW 1.5KW ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Maximum efficiency will occur, when copper loss is_______to iron loss? greater than any of the above equal to less than greater than any of the above equal to less than ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines An induction motor has a rotor resistance of 0.002 Ω / phase. If the resistance is increased to 0.004 Ω / phase then the maximum torque will increase by 100% increase by 200% remain unaltered reduced to half increase by 100% increase by 200% remain unaltered reduced to half ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The counter (or back) emf in a dc machine is 1. the same as generated emf in a dc motor 2. proportional to field flux and armature speed 3. not the same as generated emf in a dc motor 4.inversely proportional to field flux 5. proportional to number of armature conductors 6. constant from no load to full load From these, the correct answer is 2, 4, 5, 6 3, 4, 5 1, 2, 5 2, 3, 6 2, 4, 5, 6 3, 4, 5 1, 2, 5 2, 3, 6 ANSWER DOWNLOAD EXAMIANS APP
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