TN 12th Model Question Paper Electrical Machines and Appliances

No. of Printed Pages : 11
1402 (NP)
!1402NPElectricalMachines! £vÄ Gs
Register Number

Part III — Vocational Subjects
(Engineering and Technology Area )

ªß C¯¢vµ[PЮ \õuÚ[PЮ (P¸zv¯À)
ELECTRICAL MACHINES AND APPLIANCES (THEORY)
( uªÌ ©ØÖ® B[Q» ÁÈ / Tamil & English Version )

Põ» AÍÄ : 2.30 ©o ÷|µ® ] [ ö©õzu ©v¨ö£sPÒ : 90
Time Allowed : 2.30 Hours ] [ Maximum Marks : 90

AÔÄøµPÒ : (1) AøÚzx ÂÚõUPЮ \›¯õP £vÁõQ EÒÍuõ GߣuøÚ
\›£õºzxU öPõÒÍÄ®. Aa_¨£v¨¤À SøÓ°¸¨¤ß AøÓU
PsPõo¨£õÍ›h® EhÚi¯õPz öu›ÂUPÄ®.
(2) }»® AÀ»x P¸¨¦ ø©°øÚ ©mk÷© GÊxÁuØS®
AiU÷PõikÁuØS® £¯ß£kzu ÷Ásk®. £h[PÒ ÁøµÁuØS
ö£ß]À £¯ß£kzuÄ®.

Instructions : (1) Check the question paper for fairness of printing. If there is any lack of
fairness, inform the Hall Supervisor immediately.

(2) Use Blue or Black ink to write and underline and pencil to draw diagrams.

£Sv & I / PART - I

SÔ¨¦ : (i) AøÚzx ÂÚõUPÐUS® Âøh¯ÎUPÄ®. 15x1=15

(ii) öPõkUP¨£mkÒÍ ©õØÖ ÂøhPÎÀ ªPÄ® Hئøh¯
Âøhø¯z ÷uº¢öukzxU SÔ±mkhß Âøh°øÚ²® ÷\ºzx
GÊuÄ®.
Note : (i) Answer all the questions.
(ii) Choose the most appropriate answer from the given four alternatives and
write the option code and the corresponding answer.

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1402 (NP) 2

1. ø©UPõ ªß Põ¨¦¨ ö£õ¸Îß ÁS¨¦ ©ØÖ® öÁ¨£{ø» Gx GßÖ
TÖP.
(A) ÁS¨¦ F (1558C) (B) ÁS¨¦ C (1808C) &US ÷©À
(C) ÁS¨¦ A (1058C) (D) ÁS¨¦ B (1308C)
Thermal Insulation class to which Mica belongs to :

(a) Class F (1558C) (b) Class C (> 1808C)

(c) Class A (1058C) (d) Class B (1308C)

2. ªßÛ¯[QPÎÀ £¯ß£kzu¨£k® EÀø»U PhzvPÒ GÆÁõÖ
ÁøP¨£kzu¨£kQßÓÚ ?
(i) ÁmhU PhzvPÒ (ii) ö\ÆÁPU PhzvPÒ
(iii) •ÖUS PhzvPÒ (iv) GÚõ©Àk PhzvPÒ
(A) (i) & (iii) ©mk® (B) (ii) & (iv) ©mk®
(C) (i), (ii) & (iii) ©mk® (D) (i), (ii) & (iv) ©mk®
How to classify the winding wires used in electrical motors ?
(i) Round wires (ii) Rectangular straps
(iii) Stranded wires (iv) Enamelled winding wires
(a) only (i) and (iii) (b) only (ii) and (iv)
(c) only (i), (ii) and (iii) (d) only (i), (ii) and (iv)

3. _¸Ò Cøhzyµ Põµo ©ØÖ® £QºÄ Põµo°ß ö£¸UPØ£»ß :
(A) ¤ß Cøhzyµ® (B) _¸Ò Cøhzyµ®
(C) •ß Cøhzyµ® (D) EÀø»U Põµo
The product of pitch factor and distribution factor is :
(a) Back pitch (b) Coil pitch
(c) Front pitch (d) Winding factor

3 1402 (NP)

4. ÷|ºvø\ C¯¢vµzvÀ Aø» •øÓ EÀø»¯õP C¸¢uõÀ
Cøn¨£õøuPÎß GsoUøP¯õÚx :
P
(A) 2P &US \©® (B) 2 &US \©®

(C) 2 &US \©® (D) P &US \©®
The number of parallel paths offered by the wave winding of a dc Machine is :

P
(a) Equal to 2P (b) Equal to
2
(c) Equal to 2 (d) Equal to P

5. ]Ô¯ ÷|ºvø\ ªßÚ[PÎß PhzvPÒ vø\©õØÔ E¯ºÄ £Sv°¾ÒÍ
¤ÍÂÀ øÁzx JmhøÁUP¨£kÁøu RÌUPshÁõÖ SÔ¨¤kQ÷Óõ® :
(A) PmikuÀ (B) ªß£ØÓ øÁzuÀ
(C) E¸UQ CønzuÀ (D) öÁ¨£ vo¨¤øn¨¦
Small DC armature conductors are kept in the Commutator raiser slits and spot welded.
This is called :
(a) Banding (b) Soldering
(c) Brazing (d) Hot stacking

6. £À AÍ塧 C¸ ÷\õuøÚ •øÚPøͲ® JßÓõP CønUS® ö£õÊx
AÍÄ •Ò Põmk® AÍÁõÚx :
(A) §ä¯® •uÀ AÍÂhõ AÍÂØS Em£mh H÷uÝ® J¸ K® AÍÄ
(B) ¥¨ J¼ Gʨ¦®
(C) §ä¯® K®
(D) AÍÂh •i¯õ AÍÄ K®
While touching the two probes of Multimeter together the Meter should read :
(a) Any ohmic value between 0 and infinity
(b) Produces beep sound
(c) Zero ohm
(d) Infinite ohm

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1402 (NP) 4

7. ªß \Uvø¯ öÁ¨£a\Uv¯õP ©õØÔ _h ©ØÖ® \ø©UP EuÄ® \õuÚ®
__________ BS®.

(A) Sκ\õuÚ¨ ö£mi (B) ©õÄ AøµUS® G¢vµ®
(C) ªß AÚÀÁõmk (D) ªß Ak¨¦
An/A _________ converts electricity into heat to cook and bake.
(a) Fridge (b) Grinder
(c) Electric toaster (d) Electric stove

8. öÁ¨£{ø»¨¤°À EÒÍ C¸ E÷»õP[PÒ :
(i) JßÖ öÁ¨£zuõÀ AvP }m]ø¯²® ©ØöÓõßÖ SøÓ¢u }m]²®
öPõshx
(ii) Cµsk® \© }m]ø¯ öPõsi¸US®
(A) Cµsk÷© \› (B) Cµsk® uÁÖ
(C) (i) ©mk® \› (D) (ii) ©mk® \›
In Bimetallic thermostat :
(i) One metal plate has a high rate of expansion when heated and other has low
rate.
(ii) Both metals have same rate of expansion when heated.
(a) Both are correct (b) Both are wrong
(c) (i) alone is correct (d) (ii) alone is correct

9. ÷u[Põ²hß öPõmøhPøͲ® |ÖUSÁuØS £¯ß£k® áõi ÁøP Gx ?
(A) ]Ô¯ áõi (B) ö£›¯ áõi
(C) AÍÁõÚ áõi (D) CvÀ GxÄ® CÀø»
Which type of Jar is used for grating nuts and coconuts ?
(a) Small Jar (b) Big Jar
(c) Medium Jar (d) None of these

5 1402 (NP)

10. E¸øÍ öÁØÔhz x¨¦µÂ RÌUPsh •UQ¯ Ch[PÎÀ £¯ß£kQÓx
(A) ¤ÍÄPÒ, vøµa^ø»PÒ
(B) ÁõPÚ[PÎß Em¦Ó®
(C) Áͺ¨¦ »[SPÎß E÷µõ©[PÒ
(D) ÷©ØTÔ¯ AøÚzx®
The main uses of cylinder type vacuum cleaner are :
(a) Crevices, curtain fabrics
(b) Vehicles interiors
(c) To remove pet hair
(d) All the above

11. ‰ÌS® ÁøP uspº `÷hØÔ uspøµ `÷hØÖÁuØS ÷uøÁ¯õÚ
÷|µ® :
(A) 30 {ªh® (B) 30 {ªhzvØS ÷©À
(C) 5 •uÀ 10 {ªh® (D) 10 •uÀ 15 {ªh®
An immersion water heater heats the water for a time duration of :
(a) 30 minutes (b) More than 30 minutes
(c) 5 to 10 minutes (d) 10 to 15 minutes

12. T¢uÀ E»ºzv°À EÒÍ uk¨¦zvøµ E»ºzvø¯ RÌUPsh Gv¼¸¢x
PõUQÓx :
(A) ªß Avºa]°¼¸¢x
(B) •i JmiUöPõÒÁv¼¸¢x
(C) AvP öÁ¨£zv¼¸¢x
(D) ÷uøÁ¯ØÓ ö£õ¸mPøÍ EÔg_Áv¼¸¢x
The protective screen in hair drier is to prevent hair drier from :
(a) Electric shock
(b) Sticking on hairs
(c) Over heating
(d) Sucking outside things

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1402 (NP) 6

13. ø©¯Â»US Âø\ø¯ E¸ÁõUP EuÄ® £Sv :

(A) _ÇØusk (B) x¸zv

(C) _¸Ò ÁiÁ EøÓ (D) Aøh¨¦ ö£mi

The part due to which water gets the centrifugal force is called :

(a) Spindle (b) Impeller

(c) Casing or volute (d) Stuffing box

14. uõ[Q°ß EøÇUS® Põ» AÍÄ __________ ö£õÖzx Aø©²®.

(A) ö\¯À öÁ¨£{ø»ø¯ (B) E¯Âk® Põ» CøhöÁÎ

(C) £ÐÂß ußø© (D) CÖUP©õÚ ‰i°ÚõÀ

Long service life of bearing depends mainly on :

(a) Operating temperature (b) Frequency of re-lubrication

(c) Type of load (d) Sealing arrangement

15. ÁÇUPzvØS ©õÓõÚ öÁ¨£ E¯ºÄ, ªß©õØÔ Gsön°À HØ£kÁuØPõÚ
Põµn® :

(A) ªøP £Ð (B) ªß_ØÖ xsi¨£õß ö\¯¼Ç¨¦

(C) ªøP ªßÚÊzu® (D) ªß©õØÔ CǨ¦PÒ

Abnormal rise in temperature of oil in transformer may be due to :

(a) Over loading (b) Failure of circuit breaker

(c) Over voltage (d) Transformer losses

7 1402 (NP)

£Sv & II / PART - II
GøÁ÷¯Ý® £zx ÂÚõUPÐUS Âøh¯ÎUPÄ®. ÂÚõ Gs 28 &US
Pmhõ¯® Âøh¯ÎUPÄ®. 10x3=30
Answer any ten questions. Q.No. 28 is compulsory.

16. ªßPõ¨¦ EøÓPÒ ö\´¯ HØÓ ªßPõ¨¦ ö£õ¸mPÒ ¯õøÁ ?
List some of the Insulation Materials in which sleeves are made ?

17. ö|QÌÄzußø© Phzv GßÓõÀ GßÚ ?
What is meant by Flexible Wire ?

18. uõ[Q }sh |õÒ EøÇUP GkUP ÷Ási¯ |hÁiUøPPÒ ¯õøÁ ?
Name the steps to be taken to ensure long service life of the bearings.

19. ‰ßÖ {ø» 6 x¸Á 24 £ÒÍ[PÒ öPõsh ©õÖvø\ C¯¢vµzvß Aø»
ÁøP EÀ»ø»UPõÚ Akzukzu £ÒÍ[PÐUS Cøh°À EÒÍ ÷Põnzøu
Psk¤i.
Calculate the angle between the adjacent slots for a wave winding for a 3 phase having
6 pole ac machine and 24 slots.

20. ªßÚPa ÷\õuøÚ ÁøPPÒ ¯õøÁ ?
What are the different methods of testing ?

21. vÓ¢ua _ØÖ, SøÓa_ØÖ Põq®ö£õÊx £À÷|õUS AÍ Põmk® AÍÄ
GßÚ?
Explain briefly the application of multimeter to perform open circuit and short circuit
test.

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1402 (NP) 8

22. \õuõµn ©ØÖ® uõÛ¯[Q, AÚÀ Áõmk塧 ÷ÁÖ£õkPøÍ u¸P.
Distinguish between Non-automatic and automatic type electric toaster.

23. \õuõµn uspøµ }µõ ªß÷u´¨¦¨ ö£mi°À £¯ß£kzuU Thõx
Hß ?
Ordinary water is not recommended in steam iron box. Why ?

24. ªß P»UQ Khõø© ©ØÖ® AvP öÁ¨£® Eshõu¾UPõÚ Põµn®, \›
ö\´²® •øÓ ¯õx ?
State the possible causes and remedies when (i) Mixie motor is not running (ii) Excessive
heat is produced.

25. \»øÁ C¯¢vµzvß ‰ßÖ ö\¯À _ÇØ]PÒ ¯õøÁ ?
Brief the three working cycle in washing machine.

26. öÁ¨£ ªßÛøÇ°ß ø|U÷µõ® P®¤ £¯ß£kzxÁuØPõÚ C¸
Põµn[PøÍ GÊxP.
State the two features Nichrome wire has, that make it good producer of heat.

27. Eµõ´Ä \Uv GßÓõÀ GßÚ ?
What is friction head ?

28. £QºÄ Põµo GßÓõÀ GßÚ ?
Define Distribution factor.

9 1402 (NP)

£Sv & III / PART - III
GøÁ÷¯Ý® I¢x ÂÚõUPÐUS Âøh¯ÎUPÄ®. ÂÚõ Gs 35 &ØS
Pmhõ¯® Âøh¯ÎUPÄ®. 5x5=25

Answer any five Questions. Q.No. 35 is compulsory.

29. EÀø» PhzvUS ÷uøÁ¨£k® Sn[PÒ ¯õøÁ ?
What are the properties needed for Winding Wire ?

30. ‰ßÖ {ø» ‰ßÖ Phzv \©£Ð, \©©ØÓ £Ð öPõsh ªß _ØÖPÐUS
ªß vÓøÚ AÍUP EuÄ® •øÓø¯ _¸UP©õP u¸P.
Using relevant circuits, explain briefly the suitable method of power measurement for
(i) 3-phase, 3 wire balanced load (ii) 3-phase, 3 wire unbalanced load.

31. öÁ¨£ CÖS® ¤ÍõìiU ©ØÖ® öÁ¨£ CÍS® ¤ÍõìiU CµsiØS®
EÒÍ ÷ÁÖ£õkPøÍ ÂÁ›. C¢u Cµsi¾® EÒÍ Cµsk ÁøP
¤ÍõìiUSPÒ Sn[PÒ £ØÔU TÖP.
What are the differences between Thermoplastic and Thermosetting plastics ? Discuss
the properties of any two materials from each category.

32. RÌUPshÁØøÓ¨ £ØÔ ]Ö SÔ¨¦ ÁøµP.
(i) Põ¨¦ / Cøn¨¦ ‰i
(ii) öuõ[P¨£k® P®¤
(iii) ÷ÁPUPmk¨£õk Cøn¨¤
Explain briefly the following with respect to Ceiling Fan :

(i) Canopy

(ii) Suspension rod

(iii) Speed regulator

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1402 (NP) 10

33. ªßÛ¯[Q°À GkUP¨£h ÷Ási¯ vÚ\› £µõ©›¨¦ ö\¯À£õkPÒ
¯õx ?
What are the necessary actions to be taken during daily Maintenance of Motors ?

34. ªß©õØÔ°À ªßPõ¨¦ ©v¨¦ SøÓ¢uõÀ \› ö\´¯ GkUP ÷Ási¯
|hÁiUøPPøÍ GÊxP.
State the actions to be taken to rectify the problem of low insulation value.

35. ªßP»UQ°øÚ _zu¨£kzx® •øÓPøÍ GÊxP. Auß £ÊxPЮ,
{Áºzv ö\´u¾® SÔ¨¤kP.
What is the process of cleaning the Mixie ? Write down the Repairs and Remedies.

£Sv & IV / PART - IV
AøÚzx ÂÚõUPÐUS® Âøh¯ÎUPÄ®. 2x10=20

Answer all the questions.

36. (A) uõÛ¯[Q ªß÷u´¨¦¨ ö£mi°ß Aø©¨¦ ö\¯À£k® Âuzøu
£hzxhß ÂÁ›. \õuõµn ÁøP²hß Cx GÆÁõÖ ÷ÁÖ£kQÓx ?
AÀ»x
(B) AÊzuªÀ»õ ÁøP uspº `÷hØÖ® P»Ûß Aø©¨¦, ÷Áø»
ö\´²® Âuzøu £hzxhß ÂÁ›.
(a) Explain the construction and working of Automatic iron box. Also discuss in
what way automatic iron box differs from Non-automatic type.

OR

(b) Explain the construction and working of Non-pressure type storage water heater.
State its area of application.

11 1402 (NP)

37. (A) ªß AÚÀ Áõmk塧 ÁøPPøÍU TÖP. Auß ÁøPPøÍ £hzxhß
ÂÍUSP.
AÀ»x
(B) \»øÁ C¯¢vµzvÀ HØ£k® SøÓ£õkPøÍ PshÔ¢x AÁØøÓ \›
ö\´²® •øÓø¯ ÂÁ›.
(a) What are the types of Electric Toasters ? Explain its types with operation with
neat diagram.
OR
(b) List out the problems occurring in Washing Machine. How will you Troubleshoot
the errors ? Write in detail.

-o0o-

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