The voltage transformation ratio of a transformer is equal to the ratio of? Mark as favorite Copy Link primary turns to secondary turns secondary current to primary current secondary induced e.m.f. to primary induced e.m.f. secondary terminal voltage to primary applied voltage Check Answer
Natural air cooling is generally restricted for transformers up to? Mark as favorite Copy Link 1.5 MVA 5 MVA 15 MVA 50 MVA Check Answer
Which of the following statements regarding an ideal single-phase transformer having a turn ratio of 1 : 2 and drawing a current of 10 A from 200 V A.C. supply is incorrect? Mark as favorite Copy Link Its secondary current is 5 A Its secondary voltage is 400 V Its rating is 2 kVA Its secondary current is 20 A Check Answer
Increase in secondary current of a transformer brings about increase in primary current. This is possible because? Mark as favorite Copy Link primary and secondary windings are capacitively coupled primary and secondary windings are inductively coupled primary and secondary windings are conductively coupled none of the above Check Answer
In order to find the full-load efficiency of a transformer the losses which must be known? Mark as favorite Copy Link may be found by performing open circuit and short-circuit tests may be found by measuring winding resistances and calculating the I2R losses may be found by measuring the input to the primary with secondary open cannot be found except by actually loading the transformer fully Check Answer
While rising and while falling, if a wave is symmetrical, it contains? Mark as favorite Copy Link even harmonics in addition to fundamental odd harmonics in addition to fundamental both odd and even harmonics in addition to fundamental none of the above Check Answer
Dust should never be allowed to accumulate on the windings and core of a dry. type transformer because it? Mark as favorite Copy Link reduces dissipation of heat may short-circuit the windings absorbs oil and grease tends to corrode the metal surface Check Answer
For parallel operation of two single phase transformers the essential condition is that they should have the same? Mark as favorite Copy Link voltage ratio percentage impedance polarity phase sequence Check Answer
ln a step-down transformer, there is a change of 15 A in the load current. This results in change of supply current of? Mark as favorite Copy Link less than 15 A more than 15 A 15 A none of the above Check Answer
In a power or distribution transformer about 10 per cent end turns are heavily insulated? Mark as favorite Copy Link to with stand the high voltage drop due to line surge produced by the shunting capacitance of the end turns to absorb the line surge voltage and save the winding of transformer from damage to reflect the line surge and save the winding of a transformer from damage none of the above Check Answer