What is represented by windings of transformers?
The transformer represents the static elektromagnityony converter with two or more windings, prednaznachenyony is the (most frequent) for alternating-current transformation of one tension to alternating current of other tension. Transformation of energy in the transformer is carried out by the variation magyonitny field. Transformers widely apply by transfer of electrical energy on long distances, at its distribution between receivers and also in different vypryamitelny, usiyolitelny, signaling and other devices.
Windings of transformers make of copper or the alyumiyoniya. For transformers of small power, i.e. at small currents (to 25 A for air and to 45 A for oil transformers), windings carry out from the insulated conductor of round transverse section. Parallel connection of rounds gives the chance to apply the wire of round transverse section at rather big currents in windings and facilitates process of production of the last. At the big capacities and currents of the winding make of conductors of rectangular transverse section.
Apply insulating materials which have to ensure reliable functioning of the transformer in the conditions of its eksyopluatation at considerable fluctuations of heating temperature to isolation of windings and other current carrying parts of the transforyomator.
The design of windings has to provide their good cooling, so that heating temperature of windings did not exceed the limits set for the corresponding classes of isolation. Isolation of windings has to maintain without damages long impact on it of the variation electric field which is available in the transyoformator during the normal work, and short-term the overstrain, arising under operating conditions transformers. Windings of transformers have to maintain mechanical vozyodeystviye to which they are exposed in the course of assembly of the transforyomator and under operating conditions at KZ.
On the way of placement on the magnetic conductor of the winding of transforyomator can be concentric and disk чередующимися. Concentric windings carry out in the form of cylinders, razmeyoshchayemy on the magnetic conductor concentrically. Inside (is closer to the core) usually place NN winding demanding smaller isolation concerning the magnetic conductor, outside - the winding of VN (fig. 1a).
In certain cases for reduction of induced resistance of windings, i.e. for reduction magnetic the rasseyayoniya, double concentric windings (fig. 1b) in which the winding of NN is divided into two parts with identical number of rounds find application. Between half of the winding of NN place VN winding. The threefold concentric winding in which the winding of NN consists of three parts, and VN winding - of two can be in this way executed.
In the disk alternating windings of the HH and BH coil, izgotovyolenny in the form of separate disks, are placed on the magnetic conductor in the alternating order (fig. 2). All winding is subdivided into the symmetric groups consisting of one or several VN coils and located on both sides from them two or the NN nesyokolky coils. The alternating windings in practice primeyonyat only for special transformers. At high nayopryazheniye these windings do not apply because of complexity of isolation and the large number of intervals between HH and BH coils.
Structurally concentric windings carry out tsilindriyochesky, bobbin, continuous, screw, etc.
Cylindrical windings - one - and the two-layer cylindrical winding reel up from the wire of rectangular transverse section in one or several parallel wires. In three-layered (and at bigger number of layers) windings between layers leave the vertical channel. The layer of the winding is made by the rounds which are reeled up closely to each other. The beginning and the end of two-layer winding bring out of its upper part and have at the verkhyony yoke. Such windings are used as windings of NN of transformers with a power up to 630 kVA.
Multi-layer cylindrical winding reels up from the provoyod of round section placed along all rod in несколько layers between which lay isolation from cable paper. Usually such winding is carried out from two coils between which leave the vertical cooling channel. Mnogoyosloyny cylindrical windings apply as VN windings to transformers with power up to 630 kVA at voltage up to 35 kV. Cylindrical windings are simple in production, but their mechanical durability in relation to axial forces of the neveyolik (when winding the wire flatwise) as the radial sizes of windings are rather small.
Coil multi-layer winding - differs from multilayer cylindrical in the fact that it is separated on height into separate coils and therefore it is more difficult in production.
Between layers of the coil lay cable or telephone paper, and between separate coils — washers from the electrocardboard. Interfood by separate coils (it is normal through two) is done by okhlazhdayuyoshchy channels. Coil multi-layer winding applies as windings of VN of transformers with a power up to 100 kVA and up to 35 kV.
Continuous winding - it is reeled up on the spiral from the wire of rectangular transverse section. It consists of several tens disk coils connected among themselves without soldering. At production of the winding the wire in each coil is stacked flatwise on the spiral and reeled up on the izolyatsiyoonny cylinder or the steel template. Between insulating tsiyolindry and winding coils and also between separate katushyoka there are cooling channels.
Each coil consists of several rounds, and each round — of one or several parallel wires. At several parallel wires winding them is made with the turn (transposition). Nepreryvyony windings, despite complexity of their production, now widely use in transformer manufacturing thanks to their high mechanical strength. Such windings apply as windings of the highest and lowest tension of transformatoyor with a power more than 1000 kVA.
Screw windings - them reel up from several paralyolelny conductors of rectangular transverse section. Parallel wires have one above another (perpendicular to the winding axis), unlike cylindrical windings at which parallel wires keep within on the line, the parallelyyony axis of the winding nearby. Rounds of the winding stack the circular helix having one or several courses. In screw windings of the neobkhoyodim the turn (transposition) of the conductors forming one round for even current distribution between parallelnyyom wires.
The turn of wires creates such conditions under which each wire within one round alternately holds all possible positions. Screw windings can have to 20, and sometimes and more parallel wires. They as well as continuous windings, have high mechanical strength, apply them as NN windings at big currents.Top