Related Questions

Those magnetic materials are best suited for making armature and transformer cores which have ________permeability and _________hysteresis loss.
A High, high
B Low, high
C High, low
D Low, low
All coil cores are made of iron.
A True
B False
Which of the following is the main advantage of an auto-transformer over a two-winding transformer?
A Eddy losses are totally eliminated
B Copper losses are negligible
C Saving in winding material
D Hysteresis losses are reduced
The output transformer used in a power amplifier is a ___________ transformer
A 1:1 ratio
B Step-up
C Step-down
D None of the above
The changes in volume of transformer cooling oil due to variation of atmospheric tem-perature during day and night is taken care of by which part of transformer
A Conservator
B Breather
C Bushings
D Buchholz relay
Which of the following is the main advantage of an auto-transformer over a two winding transformer?
A Hysteresis losses are reduced
B Saving in winding material
C Copper losses are negligible
D Eddy losses are totally eliminated
Power amplifiers generally use transformer coupling because transformer per-mits
A Cooling of the circuit
B Impedance matching
C Distortionless output
D Good frequency response
Laminated cores, in electrical machines, are used to reduce
A Copper loss
B Eddy current loss
C Hysteresis loss
D All of the above
Cores are used to
A Form internal cavities in the casting
B Improve mould surface
C Form a part of a green sand mould
D All of these
The sand used for making cores is
A Green sand
B Dry sand
C Loam sand
D Oil sand

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