Sunday, February 17, 2013

Objective Questions From Transformers: Part-4

Transformers Objective Questions and Answers:

[1] A Buchholz relay can be installed on
A. Auto-transformers
B. Air-cooled transformers
C. Welding transformers
D. Oil cooled transformers

[2] The chemical used in breather is
A. Asbestos fibre
B. Silica sand
C. Sodium chloride
D. Silica gel

[3] Material used for construction of transformer core is usually
A. 0.4mm to 0.5 mm
B. 4mm to 5 mm
C. 14mm to 15 mm
D. 25mm to 40 mm

[4] Helical coils can be used on
A. Low voltage side of high kVA transformers
B. High frequency transformers
C. High voltage side of small capacity transformers
D. High voltage side of high kVA rating transformers

[5] The transformer ratings are usually expressed in terms of
A. Volts
B. Amperes
C. kW
D. kVA

[6] The value of flux involved in the emf equation of a transformer is
A. RMS value
B. RMS value
C. Maximum value
D. Instantaneous value

[7] The main advantage of auto transformer over a two winding transformer is
A. Hysteresis losses are reduced
B. Saving in winding material
C. Copper losses are negligible
D. Eddy losses are totally eliminated

[8] During short circuit test iron losses are negligible because
A. The current on secondary side is negligible
B. The voltage on secondary side does not vary
C. The voltage applied on primary side is low
D. Full-load current is not supplied to the transformer

[9] Which of the following properties is not necessarily desirable in the material for transformer core?
A. Mechanical strength
B. Low hysteresis loss
C. High thermal conductivity
D. High permeability

[10] The main reason for generation of harmonics in a transformer could be
A. Fluctuating load
B. Poor insulation
C. Mechanical vibrations
D. Saturation of core

12:10 PM


  1. bimal*b 27.06.2014June 26, 2014 at 11:56 PM

    In Question no.3 ans will be 0.25 to 0.5mm

  2. Replies
    1. How can "D" be the answer for quesiton 10?

    2. I think 10 no ques ans will be A ...