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A)
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hich of the following is a bidirectional Thyristor ?
SCR B) TRIAC C) IGBT D) FET

hich of the following commutation method is employed in series inverters ?
Line commutation B) Natural commutation
Load commutation D) All of the above

hich of the following is a dc regulated power supply that performs only stepdown of

[806 ?

Cuk converter B) Buck converter

Cyclo converter D) None of these

hich of the following consists of a mechanical valve operated through an electrical coil ?
Pneumatic valve B) Plug valve

Hydraulic valve D) Solenoid valve

hich of the following starter is most economical and suitable for starting a 3.5 KW SCIM ?
Auto transformer starter B) Star delta starter

Direct on line starter D) Two point starter

Two motors A and B are operated such a way that motor B should start only after
motor A has started. Which of the following arrangement is correct for this operation ?

i

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A)

Insert a normally open contact of contactor A in series with the contactor coil B.
Insert a normally closed contact of contactor A in series with the contactor coil B.
Insert a normally open contact of contactor B in series with the contactor coil A.
Only i B) Only iii C) Only iand ii D) Only ii

Which of the following sequence of connection is/are correct about an AC motor control
circuit ?

Line — Fuse — N/C push button switch — N/O push button switch — OLR — Relay coil
— Neutral

ii. Line - Fuse — N/C push button switch — Neutral — N/O push button switch —- OLR -

Relay coil
iii. Line - Fuse — N/C push button switch — N/O push button switch - OLR — Neutral -
Relay coil
Only ii 8) Only iii
Only i D) All of the above (i, ii and iii)

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