Why do you need a generator spinning to have current in its coil?kekkeroo said:why doesn't the magnetic flux going through the core result in a current in the secondary coil
A transformer cannot use DC because it relies on the changing magnetic field created by alternating current (AC) to induce a current in the secondary coil. DC does not have a changing magnetic field, so it cannot induce a current in the secondary coil.
Ampere's law states that the magnetic field created by a current-carrying conductor is directly proportional to the current and inversely proportional to the distance from the conductor. In a transformer, the changing magnetic field created by AC is necessary for the induction of current in the secondary coil. Since DC does not have a changing magnetic field, Ampere's law cannot be applied and the transformer cannot function.
No, a transformer cannot be modified to work with DC. The design and function of a transformer are specifically for AC, and modifying it to work with DC would require significant changes to the core and winding structure, making it essentially a different device.
If DC is applied to a transformer, the primary coil will create a steady magnetic field, but there will be no changing magnetic field to induce a current in the secondary coil. This means that no energy will be transferred from the primary to the secondary coil, rendering the transformer useless.
AC is used instead of DC in transformers because it is easier to change the voltage of AC using a transformer. By altering the number of windings in the primary and secondary coils, the voltage can be stepped up or down. This is not possible with DC, as it does not create a changing magnetic field and cannot be easily converted to different voltages.