134.  Buchholz's relay gives warning and protection against
A. electrical fault inside the transformer itself
B. electrical fault outside the transformer in outgoing feeder
C. for both outside and inside faults
D. none of the above

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135.  The magnetising current of a transformer is usually small because it has
A. small air gap
B. large leakage flux
C. laminated silicon steel core
D. fewer rotating parts

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136.  Which of the following does not change in an ordinary transformer?
A. Frequency
B. Voltage
C. Current
D. Any of the above

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137.  Which of the following properties is not necessarily desirable for the material for transformer core?
A. Low hysteresis loss
B. High permeability
C. High thermal conductivity
D. Adequate mechanical strength

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138.  The leakage flux in a transformer depends upon
A. load current
B. load current and voltage
C. load current, voltage and frequency
D. load current, voltage, frequency and power factor

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139.  The path of the magnetic flux in transformer should have
A. high reluctance
B. low reactance
C. high resistance
D. low resistance

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140.  Noise level test in a transformer is a
A. special test
B. routine test
C. type test
D. none of the above

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