Mainly transformer has high inductance and low resistance. In case of DC supply there is no inductance ,only resistance will act in the electrical circuit. So high electrical current will flow through primary side of the transformer. So for this reason coil and insulation will burn out.
- If DC supply is given to the transformer, the current will not change due to constant supply.
- So the mutual induction is not possible and thus the transformer will not work.
- The primary winding resistance is very small.
- For DC supply, the primary winding inductive reactance is zero.
- So the primary will draw very high current for dc supply, consequently extra heat generated and thus the transformer get damaged.
- Hence the DC supply should not be applied to the transformer.