To understand whether a transformer can be used on DC supply, first of all we have to understand about AC and DC current.
As we know about AC and DC current, the result and direction of AC current are constantly changing and the result and direction of DC current do not change continuously here are obtained in a straight line.
What would happen if the DC supply was connected to the transformer
Now if the primary winding of the transformer is connected to the DC supply then the flux in the winding will be generated but the flux will be of irreversible type, due to which no flux will be cut in the secondary winding and no EMF will be generated in the secondary winding. (EMF will be generated for a short period of time on switching on)
Thus the transformer does not give output at DC voltage. In addition, if the transformer is connected to the DC supply, the transformer can be damaged.
What will happen when the DC voltage is applied to the transformer's input
Before understanding this, we have to keep some things in our mind.
The resistance of the winding of the transformer is very low. Whenever we apply DC voltage to the input of the transformer, the reactance of its winding will be zero as the reactance as we generate depends on the frequency of the given voltage and the frequency of DC voltage. It is zero.
Here the flux that will be formed by flow of direct current on it will be constant.
When the primary winding of the transformer is connected to the DC supply, the winding of the transformer will work as if there is a short circuit at both ends of the DC voltage source, due to which a lot of current will start flowing in this circuit which results in The primary winding of the transformer will be very hot.
Even the primary winding of the DC Voltage Source or Transformer may be defective. The effect of current on the winding of the transformer depends on the given DC voltage, the resistance of the winding rating of the transformer and how powerful the DC voltage source is.