Transformers Objectives Part 03
41 . The function of transformer oil in a transformer is to provide insulation and cooling.
42 . Full load copper loss in a transformer is 1600W. At half load the loss will be 400W.
43 . A transformer has full load copper loss of 800Wand core loss of 600W. Total losses at no load will be approximately 600W
44 . Buchholz relay is used on Oil cooled transformer.
45 . Buchholz relay is generally not provided on transformer below 500KVA
46 . Operating time of Buchholz relay is of the order of 0.1 second
47 . In a distribution transformer normally core losses are less than copper losses
48 . A buchholz relay will operate in a transformer whenever there is large internal fault.
49 . Buchholz relay protection is normally not provided on small distribution transformer
50 . In a transformeropen circuit test is conducted on low voltage side and short circuit test on high voltage side.
51 . For a transformer operating at constant load current maximum efficiency will occurs at Unity power factor.
52 . The function of breather in a transformer is to arrest flow of moisture into the tank
53 . A good voltage regulation of a transformer means output voltage fluctuation from no load to full load is least.
54 . A transformer can have zero voltage regulation at leading power factor.
55 . The color of dry silica gel is pale pink
56 . The color of moist silica gel is blue
57 . The essential condition for parallel operating of two single phase transformer is that they should have the same polarity.
58 . In transformer the resistance between the primary and secondary must be infinite.
59 . The secondary of a current transformer is always short circuited under operating conditions because it avoid core saturation and high voltage regulation
60 . The main advantage of an auto transformer over two windings transformer is that only one winding is used as result there is saving in material