1. If a DC source only is connected to the primary of a linear transformer such
ID: 1813201 • Letter: 1
Question
1. If a DC source only is connected to the primary of a linear transformer such as to produce flux linking the primary and secondary coils there will be a steady state voltage generated in the secondary coil.
2. In the case of a linear transformer the reluctance of the core magnetic material would appear the same if measured from either the primary or secondary windings
3. In most transformer cores the reluctance of the airgaps is negligible when compared with the reluctance of the core material
4. Aluminum is frequently used in transformer cores because it is mechanically light, strong and is characterized by a very high relative permeability %u03BCr>>1.
5. For most low reluctance materials currently available and used in practical magnetic devices such as transformers, the slope of the BH curve may be always be considered constant over the possible range of operation of the device.
Explanation / Answer
1. If a DC source only is connected to the primary of a linear transformer such as to produce flux linking the primary and secondary coils there will be a steady state voltage generated in the secondary coil.
Ans:
See a transformer works on the basic principle of change in flux causing a voltage induced in the secondary.usualyy the primary coil is excited by a varying voltage soruce that is a AC source ,it varies with time ryt, so the flux it produces which links to the secondary coil also varies,but if only dc voltage is prvided to the primary coil,there is no change in voltage hence no change in flux which implies there is no voltage induced on the secondary coil,so no voltage is induced in the secondary coilans is false
2. In the case of a linear transformer the reluctance of the core magnetic material would appear the same if measured from either the primary or secondary windings
Reluctance just depends on the length and area and permeability of the material,hecne it will and should appear the same from either side,the primary or the secondary
3. In most transformer cores the reluctance of the airgaps is negligible when compared with the reluctance of the core material
Ans: Relucance of a material is inversly proportional to permeability of the material as the core is a magnetic material which means it permits flux to pass through it which intern means that its permeability is high compared to air
so reluctance of air is more than that of the core usually reluctance of core is negliguible when compared to air gap reluctance.
4. Aluminum is frequently used in transformer cores because it is mechanically light, strong and is characterized by a very high relative permeability %u03BCr>>1.
Aluminium is light yes,
it is strong too,
but i believe it doesnot have greater permeability compared to copper,usually copper is used.
5. For most low reluctance materials currently available and used in practical magnetic devices such as transformers, the slope of the BH curve may be always be considered constant over the possible range of operation of the device.
Relcutance is given L/UA
where L=length
A+area=permeability the slope is constant
if reluctance is low---->u is high,B is small compared to H so probably it can be assumed that
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