Top 60 MCQs of transformer | Objective type questions of transformer #1

(1) In core type transformer which winding is mostly used ?

(a) Sandwich type winding

(b) Concentric winding

(c) Cross over winding

(d) Helical winding

Answer is (b)

(2) In shell type transformer which winding is used ?

(a) Cross over winding

(b) Helical winding

(c) Sandwich type winding

(d) Continuous disc winding

Answer is (c)

(3) The cylindrical winding is used for LV coils upto________

(a) 1300 kVA

(b) 1400 kVA

(c) 1700 kVA

(d) 1500 kVA

Answer is (d)

(4) The purpose of providing an iron core in a transformer is to

(a) Providing support to windings

(b) Decreases the reluctance of the magnetic path

(c) Reduce eddy current loss

(d) Reduce iron loss

Answer is (b)

(5) The function of silica gel is

(a) To absorb heat

(b) To provide insulation

(c) To absorb moisture

(d) To absorb water content

Answer is (c)

(6) A transformer core is laminated for

(a) Reduce eddy current loss

(b) Reduce hysteresis loss

(c) Reduce copper loss

(d) None of above

Answer is (a)

(7) The transformer core is made up of

(a) Cast iron

(b) Copper

(c) Silicon steel

(d) Stainless steel

Answer is (c)

(8) The rectangular core is suitable for

(a) Low voltage transformer

(b) High voltage transformer

(c) Medium voltage transformer

(d) All of above

Answer is (a)

(9) The cross-section of the yoke is made about_______ greater than that of the core.

(a) 10 percent

(b) 15 percent

(c) 20 percent

(d) 30 percent

Answer is (b)

(10) Which winding is suitable for low voltage and large current requirement ?

(a) Disc winding

(b) Cross over winding

(c) Cylindrical winding

(d) Helical winding

Answer is (c)

(11) ANSI standard for manufacture of transformer

(a) High voltage side should lead the low voltage side by 30 degree with Y-∆ or ∆-Y connection

(b) High voltage side should lag the low voltage side by 30 degree with Y-∆ or ∆-Y connection

(c) Low voltage side should lead the high voltage side by 30 degree with Y-∆ or ∆-Y connection

(d) Low voltage side should lag the high voltage side by 30 degree with Y-∆ or ∆-Y connection

Answer is (a)

(12) If the line voltage is high and the current is small, then which connection is suitable for transformer is more economical ?

(a) Delta

(b) Star

(c) Zig-Zag

(d) None of above

Answer is (b)

(13) If the line voltage is small and the current is large, then which connection is suitable for transformer is more economical ?

(a) Delta

(b) Star

(c) Zig-Zag

(d) All of above

Answer is (a)

(14) For parallel operation of transformer which condition is necessary ?

(a) Polarity should be same

(b) Same phase sequence

(c) Same percentage impedance

(d) All of above

Answer is (d)

(15) To reduction in cost of copper which core is preferred ?

(a) Circular coil

(b) Rectangular core

(c) Stepped core

(d) Cylindrical core

Answer is (c)

(16) The commonly used forms of mitred joints is _______

(a) 35 degree

(b) 45 degree

(c) 55 degree

(d) 65 degree

Answer is (b)

(17) Tappings are provided on high voltage (HV) side because_____

(a) It has large no. of turns

(b) It has low current than LV side

(c) It has low resistance

(d) Both (a) and (b)

Answer is (d)

(18) For cooling of transformer which medium is used ?

(a) Air

(b) Oil

(c) Water

(d) All of above

Answer is (d)

(19) The formula of window space factor is _____

(a) Kw=Ac/Aw

(b) Kw=Aw/Ac

(c) Kw=Ac*Aw

(d) Kw=Ai/Aw

Answer is (a)

(20) The choice of window space factor depends upon ______

(a) kVA rating

(b) Voltage rating

(c) EMF per turn

(d) Both (a) and (b)

Answer is (d)

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