transformatorer

Transformatorer (transformers) are electrical devices that transfer energy between circuits through magnetic coupling. They consist of windings around a magnetic core. When alternating current in the primary winding changes, it creates a varying magnetic flux in the core, which induces voltage in the secondary winding. The voltage ratio equals the turns ratio N1:N2, and the currents are inversely proportional, so an ideal transformer conserves power. Real devices have losses but can achieve high efficiency.

Types and uses: Transformers come in core-type and shell-type designs. They can be two-winding units for stepping voltage up or down, isolation transformers that provide electrical separation, or autotransformers that share a winding for smaller voltage changes. They are widely used as power transformers in electrical grids, distribution transformers at substations, and in electronics for supplying devices. Instrument transformers, including current transformers and voltage transformers, provide scaled signals for measurement and protection.

Construction and operation: A laminated iron or ferrite core provides a low-reluctance path for magnetic flux; windings are typically copper or aluminum and are insulated. Many large transformers are oil- or gas-immersed for cooling, while dry-type units are common indoors or in electronics. Losses include core losses (hysteresis and eddy currents) and copper losses in windings, along with stray losses, influencing efficiency.

Frequency and maintenance: Transformers operate at design frequencies (commonly 50 or 60 Hz in power systems; high-frequency transformers are used in electronics). Maintenance involves monitoring insulation, cooling systems, oil quality, and protective devices to ensure reliability and safety.