Question

1. Hysteresis loss in a magnetic material is proportional to square of frequency and Eddy current loss can be reduced by using a high permeability magnetic material. True or false? 1 point 2. A sinusoidal voltage impressed on a coil wound around a closed magnetic circuit made of M-5 electrical steel will lead to non-sinusoidal flux and non-sinusoidal exciting current. True or False? 1 point 3. An open Delta connection can operate at a) 58% b) 68% c) 78% of rated load. 1 point 4. When the secondary of a CT is open circuited, there is a risk of overvoltage in the secondary. True or False? 1 point 5. Per-unit system eliminates the need of referring quantities from one side to the other in a transformer. True or False? point

Answer 1

Given Statement is False Ane current loss, Because hysteresis loss a frequeny 1 & Eddy current loss x (frequency)? . And Hysteresis loss can be reduced by using high permeability magnetic material not Eddy Eddy aurrent loss can be reduced by using thin' laminations. © Given statement is False An For Sinusoidal voltage imprened, flur should also be sinusoidal stree, N= No of turns VE-NAM $7 flux , for sinusoidal flux in the electrical steel cane, we a require non- sinusoidal curent as we operate the core in non-linear region Of B-(Hysteresis) curve, open Delta sated load 100 VIVI = x 3 VI. = 57.7% 589, ® is correct

6 Given statement is TRUE - When secondary of ct is open circuited , mmf due 1. to secondary is zero , hence net muy due to primary current is very large → large flux generated & have overvoltage in secondary ☺ Given statement is TRUE This i e the advantage of per-unit system.