Read the text. The transformer is a straightforward application of Faraday's Law of Electromagnetic Induction

Transformers

The transformer is a straightforward application of Faraday's Law of Electromagnetic Induction. It consists basically of two coils in close proximity. One coil of N turns is excited with alternating current and therefore establishes a flux which alternates with the current. The other coil is linked by most of this flux and thus has a mutually induced e.m.f. This e.m.f. would drive a load current through any circuit connected to the terminals of the second coil. Energy would then be transferred through the medium of the magnetic field from coil 1 to coil 2. The transformation could be from any convenient input voltage to any convenient output voltage. The coils, which consist of many turns, are wound on a laminated iron core and insulated from the iron and from each other. The core itself forms a closed iron magnetic circuit, thus ensuring a small magnetizing current. Consequently, the windings encircle the core and the core encircles the windings. There are low main ways of achieving this in a practical transformer: the core-type construction and the shell-type construction. On small transformer up to a few kVA, natural air cooling is satisfactory. For larger sizes, the transformers are usually immersed in an oil filled tank. The heat is passed to the oil which circulates round the tank by natural convection, thus carrying the heat to the tank walls whence it is dissipated. The surface area of the tank can be effectively increased by various means.

In electric power systems, transformers are used to transform electric energy at a voltage of about 10-25 kilovolts to a voltage of 50-750 kilovolts (which is suitable for long-distance transmission). When this energy arrives at the load area, it is generally transformed to a voltage in the range of 2-20 kV because this level is the most economical for distribution of smaller quantities over short distances. At a point near the premises of most customers, the energy is further stepped down to one of the standard utilization voltages, such as I 15, 230, 440 or 575 volts.

Transformers, large and small, are included in many kinds of electric and electronic apparatus to produce energy at a voltage suitable for particular load devices.

Give the Russian equivalents of the following expressions.

A straightforward application, alternating current, a mutually induced e.m.f., convenient input voltage, the second coil, small magnetizing current, the core-type construction, the shell type construction, natural air cooling, an oil filled tank.