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Which of the following does not change in a transformer ?

Which of the following does not change in a transformer ?

  1. Current
  2. Voltage
  3. Frequency
  4. All of the above
discuss
In a transformer the energy is conveyed from primary to secondary

In a transformer the energy is conveyed from primary to secondary

  1. through cooling coil
  2. through air
  3. by the flux
  4. none of the above
discuss
A transformer core is laminated to

A transformer core is laminated to

  1. reduce hysteresis loss
  2. reduce eddy current losses
  3. reduce copper losses
  4. reduce all above losses
discuss
The degree of mechanical vibrations produced by the laminations of a transformerdepends on

The degree of mechanical vibrations produced by the laminations of a transformerdepends on

  1. tightness of clamping
  2. gauge of laminations
  3. size of laminations
  4. all of the above
discuss
The no-load current drawn by transformer is usually what per cent of the full-loadcurrent ?

The no-load current drawn by transformer is usually what per cent of the full-loadcurrent ?

  1. 0.2 to 0.5 per cent
  2. 2 to 5 per cent
  3. 12 to 15 per cent
  4. 20 to 30 per cent
discuss
The path of a magnetic flux in a transformer should have

The path of a magnetic flux in a transformer should have

  1. high resistance
  2. high reluctance
  3. low resistance
  4. low reluctance
discuss
The permissible flux density in case of cold rolled grain oriented steel is around

The permissible flux density in case of cold rolled grain oriented steel is around

  1. 1.7 Wb/m2
  2. 2.7 Wb/m2
  3. 3.7 Wb/m2
  4. 4.7 Wb/m2
discuss
Sumpner's test is conducted on trans-formers to determine

Sumpner's test is conducted on trans-formers to determineA

  1. temperature
  2. stray losses
  3. all-day efficiency
  4. none of the above
discuss
The dielectric strength of transformer oil is expected to be

The dielectric strength of transformer oil is expected to be

  1. lkV
  2. 33 kV
  3. 100 kV
  4. 330 kV
discuss
No-load on a transformer is carried out to determine

No-load on a transformer is carried out to determine

  1. copper loss
  2. magnetising current
  3. magnetising current and loss
  4. efficiency of the tr
discuss
The efficiency of a transformer will be maximum when

The efficiency of a transformer will be maximum when

  1. copper losses = hysteresis losses
  2. hysteresis losses = eddy current losses
  3. eddy current losses = copper losses
  4. copper losses = iron losses
discuss
No-load current in a transformer

No-load current in a transformer

  1. lags behind the voltage by about 75°
  2. leads the voltage by about 75°
  3. lags behind the voltage by about 15°
  4. leads the voltage by about 15°
discuss
The purpose of providing an iron core in a transformer is to

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

  1. provide support to windings
  2. reduce hysteresis loss
  3. decrease the reluctance of the magnetic path
  4. reduce eddy current losses
discuss
Which of the following is not a part of transformer installation ?

Which of the following is not a part of transformer installation ?

  1. Conservator
  2. Breather
  3. Buchholz relay
  4. Exciter
discuss
While conducting short-circuit test on a transformer the following side is shortcircuited

While conducting short-circuit test on a transformer the following side is shortcircuited

  1. High voltage side
  2. Low voltage side
  3. Primary side
  4. Secondary side
discuss
In the transformer following winding has got more cross-sectional area

 In the transformer following winding has got more cross-sectional area

  1. Low voltage winding
  2. High voltage winding
  3. Primary winding
  4. Secondary winding
discuss
A transformer transforms

A transformer transforms

  1. voltage
  2. current
  3. power
  4. frequency
discuss
A transformer cannot raise or lower the voltage of a D.C. supply because

A transformer cannot raise or lower the voltage of a D.C. supply because

  1. there is no need to change the D.C. voltage
  2. a D.C. circuit has more losses
  3. Faraday's laws of electromagnetic induction are not valid since the rate of change of flux is zero
  4. none of the above
discuss
Primary winding of a transformer

Primary winding of a transformer

  1. is always a low voltage winding
  2. is always a high voltage winding
  3. could either be a low voltage or high voltage winding
  4. none of the above
discuss
Which winding in a transformer has more number of turns ?

Which winding in a transformer has more number of turns ?

  1. Low voltage winding
  2. High voltage winding
  3. Primary winding
  4. Secondary winding
discuss
total MCQs: 133

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