Transformer Function

A transformer consists of a magnetic circuit, called the core, and has at least two windings through which current and voltage flow, with a fixed number of turns. The winding facing the electrical voltage (mains voltage) is called the primary side (primary coil), while the side with the load and the electrical consumer is called the secondary side (secondary coil). The incoming power, consisting of current and voltage, is transformed into outgoing power, consisting of current and voltage.

A transformer essentially consists of two or more coils and a common iron core. In a single-phase transformer, often only one coil is used, while in higher power transformers, two coils are connected in parallel or series. The three-phase transformer consists of three coils, which are connected according to the desired connection group. The windings of a transformer are typically made of insulated copper wire and are wound onto the iron core, either onto a separate spool or with spacers and insulation, while maintaining air gaps and creepage distances. The alternating voltage is connected there, generating a changing magnetic field. The magnetic flux passes through the secondary coil with the help of the iron core. On the secondary side of the transformer, the output alternating voltage (induced voltage) can thus be taken with the desired alternating current. The winding ratio of the primary and secondary coils defines whether the output voltage is smaller or larger than the input voltage. If the number of turns on the secondary coil is greater than that of the primary coil, the output voltage is higher than the input voltage. However, if the number of turns on the secondary coil is lower, the output voltage is lower than the input voltage. The key to the change in power or alternating voltage and current is the turn ratio N1/N2. The wire gauge used on the coils is defined by the current.