Electrical Engineering · Question Bank

Transformers

110 of 258 questions match · page 6 of 6. Answer in your head first, then check the solution.

📘 EE Mock Board Exam

#101📘 EE Pocket Reviewer RojasEasy

What is the reason why the transformer cores are laminated?

ATo simplify its construction

BTo minimize eddy current loss

CTo reduce the cost

DTo reduce the hysteresis loss

#102📘 EE Pocket Reviewer RojasEasy

Which one is considered a main advantage of an autotransformer over a conventional two winding transformer?

AContinuously varying voltage is available

BConsiderable saving in the winding materials

CCopper losses are considerably reduced

DBoth A and B

#103📘 EE Pocket Reviewer RojasEasy

Which of the following can be determined with the open circuit test in a transformer?

AFull load copper loss

BIron loss

CFull load efficiency

DEquivalent winding resistance

#104📘 EE Pocket Reviewer RojasEasy

The savings in copper achieved by converting a two-winding transformer into an autotransformer is determined from which of the following?

AVoltage transformation ratio

BLoad connected on the secondary

CSize of the transformer core

DType of material used as the core

#105📘 EE Pocket Reviewer RojasEasy

Which one is the biggest advantage of T-T connection over the V-V connection for 3-phase power transformation?

AIt provides a set of balanced voltages under load

BIt provides a true 3-phase, 4-wire system

CIt provides a higher ratio of utilization

DIt provides more voltages

#106📘 EE Pocket Reviewer RojasEasy

Which of the following is a determining factor for the reactance of the transformer?

ALeakage flux

BMutual flux

CSize of the core

DPermeability of the core

#107📘 EE Pocket Reviewer RojasEasy

What is the reason why the secondary of a current transformer is short-circuited before the meter is removed?

ATo protect the primary circuit

BFor safety purposes of the electricians

CTo avoid core saturation and high voltage induction

DAll of these

#108📘 EE Pocket Reviewer RojasEasy

In a transformer, what is reason why the leakage flux of each winding is proportional to the current in that winding?

AThe leakage paths do not saturate

BThe two windings are electrically isolated

CThe mutual flux is confined in the core

DOhm's law applies to magnetic circuits

#109📘 EE Pocket Reviewer RojasEasy

What is the reason why transformers have good all day efficiency?

AIts copper loss is low

BIts core loss is low

CIts copper and core losses are both low

DIt is only loaded few hours in a given day

#110📘 EE Pocket Reviewer RojasEasy

What is the effect of leakage flux in a transformer?

AIt will increase the copper loss

BIt will cause voltage drop in the windings

CIt will increase the eddy current loss

DIt will cause the life of the core to shorten

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