Electrical Machines Questions and Answers_pag344

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Answer: a 
Explanation: Concentrated winding have all turns on one magnetic axis. 
2. DC machines have ________ windings and synchronous machines use ______ windings. 
a) closed,open 
b) open, closed 
c) open, open 
d) closed, closed 
View Answer 
Answer: a 
Explanation: All the commutator machines use closed winding as it has nothing to deal with 
reactance. In ac machines, the winding can be converted 
to star to delta and vice versa. 
3. We can place closed windings in 
a) ac commutator machine 
b) stepper motor 
c) ac machine 
d) dc machine 
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Answer: a 
Explanation: Closed windings are placed only in commutator as it does not need any 
reconnections later. 
4. Which of the following machines can be used to place open slot winding? 
a) ac machine 
b) ac commutator machine, ac machine 
c) dc machines 
d) all of the mentioned 
View Answer 
Answer: a 
Explanation: Only ac machines are used for open type of winding inside the machine. 
5. The simplex lap winding has the range of winding pitch of 
a) (-2,2) 
b) (-1,1) 
c) more than 2 
d) less than 1 
View Answer 
Answer: a 
Explanation: For a progressive winding, forward pitch – backward pitch = winding pitch 
yb= coil sides/P +or-1 (m) 
 Here m is such that to make yb an odd integer. 
6. The commutator pitch for a simplex lap winding is equal to 
a) 1 and -1 
b) 1 
c) -1