JPS6348136A - Armature winding - Google Patents

Abstract

PURPOSE:To make the allotment of surge voltage uniform to improve insulating properties, by setting the length of a part projecting from the edge of an iron core in the winding connected to the power supply line longer than the other winding. CONSTITUTION:Enclosed in a slot, multiple windings 2a-2c are installed to an iron core 1. Each winding 2a-2c is connected in series each other. The winding 2a on the leftest side is connected to a terminal 3, through which it is connected to the power supply line. The winding 2a connected to the power supply line is formed longer in coil side dimension than the other windings 2b and 2c, with which the part projecting from the edge of the iron core 1, e.g. the length of the straight line section is set longer than B in the other windings 2b and 2c. Thus the allotment of surge voltage can be made uniform and the insulating properties improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to an armature winding in which a plurality of windings are installed in slots of an iron core and connected in series with each other.

(Prior art) For example, the armature winding of a three-phase rotating electric machine is constructed by connecting a plurality of windings in series for one phase, and one end of the series circuit is connected to a power supply line, and the other end is connected to a power supply line. The side is commonly connected to the anti-type source side ends of the other two phases to form a star connection. and,
Although each winding has a different number of windings and a dimension between the coil sides depending on the number of poles and the number of slots, the length dimension of the coil sides is all the same corresponding to the core length. Therefore, the length of the portion of each winding protruding from the core end is generally the same for all windings.

However, if a voltage with a steep rise characteristic is applied to the armature windings with such a configuration, the windings closer to the power supply line will share the higher voltage, which can sometimes lead to dielectric breakdown. There was the problem of inviting. According to various data,
Approximately 60% of the surge voltage is applied to the winding connected to the power supply line.
In some cases, a large voltage was applied.

A general analysis of this results in the following. Each winding has resistance, self-inductance, mutual inductance, and capacitance. If we examine this capacitance in detail, we will find that it is the series capacitance, which is the sum of the capacitance between each winding and the capacitance between the wires that make up each winding, and the series capacitance that is Consists of stray capacitance. Here, since the series circuit of the winding group can be viewed as a distributed constant circuit, let us assume that the series capacitance is K and the stray capacitance is C.
(C/K)+, the shared voltage e in each wire is expressed by the following equation.

5Lnhα
...(1) sin hα Here, E is the surge voltage, and X is the electrical distance from the neutral point of the winding (assuming the whole is 1). When formula (1) is illustrated using α as a parameter, it becomes as shown in 5, which is not shown in FIG. As is clear from the figure, when α-0, an equipotential distribution is obtained, or as α increases, the bias of the voltage distributed to the windings on the power supply line side becomes larger.

(Problems to be Solved by the Invention (7)) As described above, when a steep voltage is applied to the conventional armature winding C, the winding is not suitable for the power supply line. There was a problem in that the voltage was shared, leading to dielectric breakdown.

SUMMARY OF THE INVENTION Therefore, it is an object of the present invention to provide an armature winding that can equalize the distribution of voltage as much as possible and improve insulation.

[Structure of the Invention] (Means for Solving the Problems) The armature winding of the present invention has a length θ of a portion of the winding connected to the power supply line that protrudes from the end of the core. The feature is that the winding is set larger than that of the winding.

(Function) In configuration No. 14, since the series capacitance K of the winding increases, α in equation (1) decreases, and as is clear from FIG. 2, the shared voltage to the winding on the power supply line side decreases. The bias becomes smaller.

(Example) One embodiment will be described with reference to FIG.

A plurality of windings 2a, 2b, 2e, . . . (three shown) are housed in slots (not shown) and installed on the iron core 1. Each winding 2a, 2b, 2e.

... are connected in series with each other, and the winding 2a is shown on the leftmost side of the figure.The winding 2a is connected to a terminal 3, and is connected to a power supply line (not shown) via this terminal 3. The winding 2a connected to this power supply line is formed to be longer than the other windings 2b, 2e, etc. due to the side dimensions of the coil.
, the length dimension A of the part protruding from the end of the core 1, for example the straight part, of the other winding 2b.

It is set to person from that B of 2c...

In the above configuration, since the target capacitance K in the winding 2a increases compared to the other windings 2b, 2c, . . . , α decreases. For example, the iron core length is 100mmSA-2100mm
5A-25, x-0,8 in formula (1)
, calculating the value for α-5, A = B = 5
α is approximately 15 compared to the armature winding of the conventional configuration with +nm.
%, the voltage concentration on the winding 2a is reduced by about 20%. Therefore, it is now possible to effectively prevent dielectric breakdown caused by this surge voltage, which is extremely beneficial for the armature windings of rotating electric machines, where steep surge voltages are frequently applied. .

In addition, in the embodiment described in -1-, the winding 2 connected to the power supply line
Although only the straight portion of the winding a is set to have a larger protrusion dimension from the end of the core 1 than the other windings, the present invention is not limited to this, and the straight portion of the core of the windings 2a, 2b, 2c, etc. The protruding dimension from 1 may be made smaller gradually as the distance from the power supply line increases. In addition, it is not limited to the straight part, but the length of the coil end part may be increased while maintaining the same length.The point is that the winding connected to the power supply line protrudes from the end of the core more than other windings. It is sufficient to set it so that the length ζJ of the portion becomes large.

``Configuration of the Invention As described above, the present invention has the length of the portion of the winding connected to the power supply line that protrudes from the iron core end set to be longer than that of other windings, so that surge This has the excellent effect of making it possible to equalize the voltage distribution as much as possible, thereby greatly improving the insulation properties.

[Brief explanation of the drawing]

FIG. 1 is a developed view of an armature winding showing an embodiment of the present invention;
FIG. 2 is a diagram showing the voltage resistance of the winding against surges. In the drawings, 1 is an iron core, and 2a, 2b, and 2c are windings. Applicant Toshiba Corporation 28 windings

Claims (1)

[Claims] 1. In a case where a plurality of windings are installed in slots of an iron core and connected in series, the length of the portion of each winding connected to the power supply line that protrudes from the end of the iron core is , an armature winding characterized by being set larger than that of other windings.