A transformer is an electrical device used for converting electrical energy. It is an indispensable and important component in the power grid. It can convert an alternating current with one voltage and current into another alternating current with the same frequency. Transformers are used in almost all electronic products. Its principle is simple, but the winding process of the transformer varies depending on different usage scenarios (different purposes). The functions of a transformer mainly include: voltage transformation; impedance transformation; isolation, voltage stabilization (magnetic saturation transformer), etc. The common iron core shapes of transformers are generally E-shaped and C-shaped iron cores. In different environments, the uses of transformers vary, such as:
1.When conducting long-distance transmission, increasing the voltage can reduce the electrical energy loss on the transmission lines.
2. When arriving at the usage area, reducing the voltage can meet the electricity demands of different users.
3. When performing impedance matching, using transformer connections can achieve the effect of changing impedance.
4. By using an isolation transformer, the two-phase electricity can be isolated to prevent the occurrence of electric shock accidents.
The working principle of a transformer:
A transformer consists of an iron core (or magnetic core) and coils. The coils have two or more windings, among which the winding connected to the power source is called the primary winding, and the remaining windings are called secondary windings. It can transform alternating voltage, current and impedance. A simple iron core transformer is composed of an iron core made of soft magnetic material and two coils with unequal number of turns wound on the iron core. The function of the iron core is to enhance the magnetic coupling between the two coils. To reduce eddy currents and hysteresis losses inside the iron core, the iron core is made of laminated painted silicon steel sheets. There is no electrical connection between the two coils, and the coils are wound with insulated copper wires (or aluminum wires). One coil is connected to the alternating current source, called the primary winding (or the original winding), and the other coil is connected to the electrical appliance, called the secondary winding (or the auxiliary winding). The actual transformer is very complex and inevitably has copper losses (heating due to coil resistance), iron losses (heating of the iron core), and leakage magnetic flux (magnetic induction lines closed in the air). The condition for the ideal transformer to hold is: ignoring the leakage flux, ignoring the resistance of the primary and secondary windings, ignoring the loss of the iron core, and ignoring the no-load current (the current in the primary winding when the secondary winding is open-circuited and the current in the primary winding). For example, when a power transformer is operating under full load (the secondary winding outputs the rated power), it is close to the ideal transformer condition.
