SU760322A1 - Contact-free dc generator - Google Patents

Description

The invention relates to electrical. rectifier machines and can be used for brushless synchronous generator pathogens. five

Known alternators with rectifiers, performing the functions of DC generators, in particular the causative agents of more powerful synchronous machines. Under certain conditions in these generators, the phenomenon of almost double current overloading of the armature and rectifier circuits is observed during emergency shutdown of one branch [1]. 15

According to the technical requirements for excitation systems, the regime in the absence of one phase or branch should be allowed without restrictions in the operation. 20

The phenomenon mentioned above forces either to impose restrictions on the regime, without one phase or a branch, or to increase reserves, i.e. the consumption of materials on the pathogen versus the necessary - 25 Mogo in a symmetric mode.

To reduce the multiplicity of overload when one branch is disconnected, the armature windings with an increased number of parallel branches are used so that 30

2

the slot of the two-layer winding was located not less than 4 sectional sides belonging to various parallel branches of this and opposite phase.

However, this solution is not appropriate for all types and capacities, in particular. Applied to brushless exciters of 300 IMF turbogenerators, it has the following drawbacks: the reduced number of slots leads to insufficiently constructive armature size ratios, the design of the winding and its manufacturing technology are complicated, the mounting of the winding in the slots becomes complicated and its cooling conditions deteriorate.

Also known is a contactless DC generator, made in the form of a synchronous machine with a multiphase armature winding connected to a load via rectifiers, with an electromagnetic inductor, which is made with two excitation windings., One of which is distributed and shifted in space by 90 el. relation to the other, concentrated winding [2]. Optimum conditions for using such a machine in symmetric modes reached 3,760,322.

They are used in a bridge rectification circuit and a two-layer armature winding with a diametral pitch with the number of grooves per pole and phase q = 1/2, with two sectional sides in each groove of the armature core.

However, the known design has a significant drawback - in asymmetrical modes without a single phase. The current overload coefficient of the phase remaining in the work, electrically opposite to the disconnected one, is -1.8. To increase the reliability of the machine, it is necessary to increase its dimensions. This leads to a deterioration in the use of active materials.

The purpose of the invention is to improve the use of materials by reducing the load factor in asymmetrical modes.

To achieve this goal. the armature winding is performed with the first 20 partial groove steps

(ABOUT

where t is the number of phases;

d - The number of grooves on the pole and phase; ξ -1 is for odd m; · ^E

Λ -2-for even t.

FIG. 1 shows an example of an unfolded armature winding circuit; 2, the arrangement of the sectional sides of the video phase and the phases located in the neighborhood of it in the slots of the armature core.

The proposed machine is made with the number of armature slots Ζ »24 (numbered), with the number of poles 2p = 6, with the number 35 phases w = 8, the connection of the phases is a star, the rectification scheme is a multiphase bridge. Phases are designated C1, C2, ... C8.

The depicted winding is a wave-type winding for which the relation between the partial steps is true.

Y, + Y _g "2 / p (2)

For all cars, the ratio

Ζ "2 rtd (3)

For machines with a diametric pitch from (2) and (3) receive

V ν ' ⁷ !' ¹ " ⁹ MS. ⁵⁰

To implement the invention, it is necessary that a separate phase of the armature within the latter be located in grooves next to two or more other 55 phases, for example, two (Fig. 1 and 2). This is ensured under the condition

U, * Y _g (5)

At the same time, in order to maximize the use of anchor volume, it is necessary that the difference between y and _y be as small as possible.

Under these conditions, (4) and (5) imply (1) · ........ '

For the proposed example, by formulas (1) and (2), it turns out

ν (β-2) | --3;

Under these conditions (Fig. 2), each phase, for example, C1 (highlighted in bold in Fig. 1), is located

¹⁰ is adjacent to two other C4 and C6.

Thus, for a wave-type winding, the invention is realized due to the inequality of the Partial steps

15 each other. .

For loop type windings, the invention is realized either by shortening (lengthening) the first partial step, or by using the number of poles 2ru 2 at the diametral step, but in the latter case, the well-known parallel connection of valves of one phase is used to improve the current distribution.

When the generator of this type is operating, a two-layer armature winding with a bridge rectifying circuit almost all flows around the current and is a double conductive layer near the surface of the armature. According to the Lenz principle, such EMFs and currents should arise in it, which would strive to destroy the cause of their cause, in particular, the inductor magnetic field. This is fairly accurate for the short-circuit of the armature winding and partially valid for the operating mode in part of the field. Therefore, the spatial distribution of currents in the armature winding must reproduce the spatial distribution of currents in the winding of the amperages of the compensation winding. In the symmetric mode, the currents in the armature are distributed evenly between the conducting layers due to the symmetry of the winding. When one phase is disconnected, one conductive layer is disturbed in the slots of the location of the disconnected phase. Consequently, according to the Lenz principle, its remaining conducting layer in these slots should accept its function. For example, the C1 phase is disabled. Then in half of the grooves where it is located, only the conductors of the C4 phase remain, and in the other half - only the conductors of the Sb. phase. They must, according to the Lenz principle, accept the current load of the C1 phase equally, i.e. overload of each of the nickname is not more than 1.5, which is almost acceptable.

Claims (1)

Claim Contactless DC generator, made in the form of synchronous-. '760322 machine with a multi-phase two-layer anchor winding having two sectional sides in each slot of the armature core connected to the load through rectifiers assembled in a bridge circuit containing an electromagnetic inductor, with two excitation windings, one of which is distributed and shifted in space with respect to another concentrated winding on 90 el.grad, characterized in that, with the aim of improving. use of materials by reducing the overload factor in asymmetrical modes, the armature winding is performed with the first partial step along the grooves y> (t ± ξ) d, where m is the number of phases; d is the number of grooves per pole and phase; ξ = 1-for odd m) ξ = 2-for even m.