Question 581. 8.  A transformer designed for operation on 60 Hz supply is worked on 50 Hz supply system without changing its voltage and current ratings. When compared with full load efficiency at 60 Hz, the transformer efficiency on full load at 50 Hz will

Question 582. 0.  Open-circuit (oc) and short-circuit (sc) tests on an AC generator are conducted under which of the following conditions? 1. oc test at nominal flux and sc test at nominal current.2. oc test at reduced flux and sc test at reduced current.3. oc test at zero armature current and sc test at reduced flux.4. oc test at zero current and sc test at nominal flux. Select the correct answer using the codes given below :Codes :

Question 583. 1. The given figure represents a trans former with two windings 1 and 2 wound on the core as shown. By applying a volt age Vi across winding 1, a voltage V2 is induced across winding 2. In an idealised condition V2 would lag Vi by ?> V2

Question 584. 9.  A transformer has a core loss of 200 W and a full load copper loss of 800W The maximum efficiency ofthe transformer will occur at

Question 585. 4.  The series equivalent impedance of a single-phase transformer referred to its secondary side is Ze2 = Re2 + jXe2. The voltage regulation of this transformer will be zero when the power factor of the load is Xe2

Question 586. 3.  The voltage regulation of a large transformer is mainly influenced by

Question 587. 2.  The leakage flux in a transformer depends upon the

Question 588. 6. If the height to width ratio of the window of coretype transformer ii increased, then

Question 589. 5.  If a saw-cut is made in the iron core of a single phase transformer as shown in the givng figure, with secondary terminals open, it will result in

Question 590. 9.  In a 3-phase power transformer, 5-limbed construction is adopted to