Working Principle of Transformer
The basic working principle of Transformer is “Faraday’s law of electromagnetic induction”
According to Faraday’s law, whenever there is a relative space (or) time variation between magnetic field and set of conductors an emf will be induced in set of conductors.
Basic requirements to generate E.M.F
According to Faraday’s law,
1. Magnetic field
2. Set of conductors
3. Relative variation in space or time between magnetic field and set of conductors.
The emf induced in set of conductors due to relative space variation w.r.t magnetic field is called dynamically induced emf.
Ex: DC Generator
The emf induced in set of conductors due to relative time variation w.r.t magnetic field is called statically induced emf.
Dynamically Induced emf:
Magnitude of dynamically induced emf can be found by flux-cut rule
according to flux-cut rule, the magnitude of dynamically induced emf
E = Blv sinθ
Where θ = angle between B and V
B=Flux density in Tesla af steady magnetic field.
V=Linear velocity with which conductor is being moved.
l =effective length of conductor.
The direction of dynamically induced emf can be found by “Fleming right hand rule”.
Fore finger→ Direction of flux.
Thumb→ Direction of motion of conductor.
Middle finger→ Direction of induced emf.
according to Fleming right hand rule the induced emf is always in the direction outward perpendicular to the plane containing velocity and flux density vectors
Statically induced emf:
The magnitude of statically induced emf can be found by Faraday’s second law.
According to Faraday’s second law magnitude of statically induced emf is equal to rate of change of flux linkages.
Nϕ = flux linkage
“-” sign shows lenz’s law