How Do Transformers Work?
Liang Zhang
General Manager at ENC GROUP LTD. Specializing in electrical insulation materials, transformer materials and spare parts.
An electrical transformer uses Faraday’s electromagnetic induction law to work – “Rate of change of flux linkage with respect to time is directly proportional to the induced EMF in a conductor or coil”.
A transformer’s physical basis lies in the mutual induction between two circuits that are linked by a common magnetic flux. It is usually equipped with 2 windings: primary and secondary. These windings share a magnetic core that is laminated, and the mutual induction that takes place between these cricuits helps transfer electricity from one point to another.
Depending on the amount of linked flux between the primary and secondary windings, there will be different rates of change in flux linkage. To ensure maximum flux linkage, i.e. maximum flux passing through and linking to the secondary winding from the primary, a low reluctance path is placed common to both windings. This leads to greater efficiency in working performance, and forms the core of the transformer.
The application of alternating voltage to the windings in the primary side creates an alternating flux in the core. This links both windings to induce EMF in the primary as well as the secondary side. EMF in the secondary winding causes a current, known as load current, if there is a load connected to the secondary section.