Electrical Machines Questions and Answers_pag2

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b) 1/2 mv​2 
c) 1/2 mv 
d) Jw​r​
2 
View Answer 
Answer: b 
Explanation: Energy stored is kinetic energy, since the system is of linear motion. 
5. In an electro-mechanical energy conversion device, the coupling field on the 
(i) electrical side is associated with emf and current 
(ii) electrical side is associated with torque and speed 
(iii) mechanical side is associated with emf and current 
(iv) mechanical side is associated with torque and speed 
From the above, the correct statements are 
a) (i) & (ii) 
b) (ii) & (iii) 
c) (iii) & (iv) 
d) (i) and (iv) 
View Answer 
Answer: d 
Explanation: The coupling field will be associated with the electrical quantities on electrical side 
and vice versa. 
6. A coupling magnetic field must react with 
(i) electrical system in order to extract energy from mechanical system 
(ii) mechanical system in order to extract energy from mechanical system 
(iii) electrical system in order to extract energy from electrical system 
(iv) mechanical system in order to extract energy from electrical system 
(v) electrical or mechanical system for electro-mechanical energy conversion 
From the above, the correct statements are 
a) (i), (ii) & (iii) 
b) (ii), (iii) & (v) 
c) (ii), (iii) & (iv) 
d) (ii), (iii) & (v) 
View Answer 
Answer: b 
Explanation: To convert electrical to mechanical, the coupling magnetic field must take energy 
from input, the electrical system and vice versa. 
7. The developed electromagnetic force and/or torque in electromechanical energy conversion 
system, acts in such a direction that tends to ___________ 
a) increase the stored energy at constant mmf 
b) decrease the stored energy at constant mmf 
c) decrease the co-energy at constant mmf 
d) increase the stored energy at constant flux 
View Answer 
Answer: b