Primary of Transformer is connected to D.C. supply
Q. What will happen if the Primary of the Transformer is connected to D.C. of the same Magnitude?
- A d.c. current will not produce the alternating flux and hence there will not be any self induced E.M.F. to oppose the supply voltage.
- Moreover the winding resistance is very less and thus it will take a very high current and this will produce a tremendous heat and winding insulation will burn out.
- Moreover due to high d.c. current core will be damaged due to magnetic losses. So transformer should never be connected to D.C.
Deep Explanation of Why is the transformer not connected to the DC?
- Transformer works on Faraday’s principle of “mutual induction”, in which an EMF is induced in the transformer secondary coil by the magnetic flux generated by the voltages and currents flowing in the primary coil winding.
- Faraday’s law of Electromagnetic Induction state that, whenever a conductor cuts magnetic field or vice versa an emf will induce in the conductor. As per the statement, a changing(moving) conductor or a changing magnetic flux is required to induce an emf in the conductor.
- In a transformer there is no moving conductor. When we apply a DC to primary winding, a constant magnetic flux induces around the coil. The Flux from primary winding passes through the secondary winding. However the linked magnetic flux in the secondary winding is constant(DC), there is no induced emf in the conductor(secondary winding).
- When we apply AC to primary winding, a changing magnetic flux is induced in the primary winding which passes through the secondary winding. As per Faraday’s law this moving magnetic flux cuts the secondary winding(conductor) and induce a voltage in the secondary winding.
the windings of the transformer are more or less, like inductor windings.
so the primary voltage to be given
V= L di/dt .
so imagine giving DC voltage to it.
your di/dt =0.
as the current will not be time varying.
so V=0 .
literally your transformer will burn out.
so we do not use DC in transformer.