Transformers Objectives Part 06

101 . Maximum regulation of a transformer occurs at lagging power factor

102 . Impedance matching transformer are used for measuring low voltages and low currents

103 . In a transformer on no load the input voltage leads the magnetizing current by 90

104 . In a transformer the voltage induced in the secondary windings lags the flux by 90

105 . The maximum load that a power transformer can carry is limited by its voltage ratio

106 . The constant power losses of a transformer loss are eddy current and hysteresis losses

107 . Transformer size can be reduced when the flux density in a transformer core is increased

108 . When the transformer core is made up of core then the eddy current loss will be more

109 . Porcelain bushings on transformer are normally not used beyond 11KV

110 . The secondary of a current transformer under operating condition is short circuited to avoid core saturation and high voltage induction

111 . Back to back is used to determine the efficiency of two identical transformer at full load

112 . The inductance of a transformer depends on leakage flux

113 . Horn gap is used to prevent the damage of a transformer due to lighting and switching

114 . The voltage regulation of a transformer can be zero when the power factor is leading

115 . The value of useful flux least depends on load

116 . In an auto transformer the primary winding is same as the secondary winding

117 . The characteristics of a voltage transformer are voltage remain constant, current varies with load

118 . The magnetizing current of a transformer usually small because it had small airgap

119 . In a dry type transformer accumulation of dust on the winding and core is likely to cause reduction in heat dissipation

120 . Delta primary, star secondary of transformer will give the highest secondary voltage