RU2510771C1 - Method for determination of impregnation coefficient for electrical machines coils - Google Patents

Abstract

FIELD: electricity.

SUBSTANCE: invention relates to electric engineering and namely to method for determination of impregnation coefficient for coils of electrical machines connected in star with insulated neutral. According to the method for determination of impregnation coefficient for coils of electrical machines characterising degree of filling by impregnating compound of coil cavities for each coil in this batch electrical parameters are measured before impregnation and after impregnation and drying; among selected electrical parameters there are capacities of two phases of star-connected coil, which are measured in turn before impregnation C_BI12, C_BI13, C_BI23 and after impregnation C_AI12, C_AI13, C_AI23 in regard to the ground; thereafter by measurement results impregnation coefficient is defined for each two phases K_IMP12, K_IMP13, K_IMP23 by mathematical relationship, then impregnation coefficients are defined for each phase of coil by mathematical relationships.

EFFECT: possibility to define the averaged impregnation coefficient and distribution of impregnating compound among phases of coil thus increasing informativity and accuracy of control.

2 tbl, 3 dwg

Description

The invention relates to electrical engineering, and in particular to a method for determining the coefficient of impregnation of the windings of electrical machines connected to a star with an isolated neutral.

There is a method of controlling the quality of impregnation of the windings of electric machines, proposed in [2], which consists in measuring the capacity of the winding relative to the magnetic core before impregnation of the BDT and the capacity relative to the magnetic core after impregnation and drying of the winding of the SPP, and it is proposed to judge the quality of the impregnation by the coefficient of impregnation Kpr determined from the expression

$$\mathrm{TO}PR=\frac{\mathrm{FROM}PP}{\mathrm{FROM}dP}(\mathrm{one})$$

The disadvantage of the analogue method is the low accuracy of control, since the values of Sdp and Cnp depend on the location of the turns in the winding, as well as on how the composition was distributed along the body cavities of the winding. If the same amount (mass) of impregnating compound gets into two different identical windings of the same batch of CRC, determined by the formula (1), can give significantly different values from each other. Therefore, the formula (1) does not allow to objectively judge the saturation of the winding cavities with an impregnating composition.

Closest to the claimed method is a method for determining the coefficient of impregnation of the windings described in [2], partially eliminating the above disadvantages of the analogue.

In the prototype method [2], according to which each winding from a given batch measures capacitances relative to the housing before impregnation and after impregnation and drying, one of the windings, arbitrarily selected from this batch, after measuring capacitance relative to the housing before impregnation, is immersed in an impregnating liquid with the known dielectric constant of the winding and measure the capacitance relative to the housing without removing the winding from the impregnating liquid, and the impregnation coefficient for each of the remaining windings of this batch is determined by the formula

$$\mathrm{TO}PR=\frac{\mathrm{one}}{\ln {\epsilon }_2}\ln \frac{{\epsilon }_{\mathrm{one}}{\mathrm{FROM}}_{PP}(\frac{{\mathrm{FROM}}_{PP}^{*}}{{\mathrm{FROM}}_{dP}^{*}}-\mathrm{one})}{\frac{{\mathrm{FROM}}_{PP}^{*}}{{\mathrm{FROM}}_{dP}^{*}}{\mathrm{FROM}}_{dP}({\epsilon }_{\mathrm{one}}-\mathrm{one})-{\mathrm{FROM}}_{PP}({\epsilon }_{\mathrm{one}}-\frac{{\mathrm{FROM}}_{PP}^{*}}{{\mathrm{FROM}}_{dP}^{*}})}(2)$$

- емкость произвольно выбранной обмотки относительно корпуса до пропитки; $${С}_{пп}^{*}$$

- емкость произвольно выбранной обмотки относительно корпуса после выдержки в пропиточной жидкости с известной диэлектрической проницаемостью до полного заполнения ею полостей обмотки; ε₁ - диэлектрическая проницаемость пропиточной жидкости; ε₂ - диэлектрическая проницаемость отвержденного пропиточного состава.where C _dp , C _pp - winding capacity relative to the housing, respectively, before impregnation and after impregnation and drying; $${\mathrm{FROM}}_{dP}^{*}$$

- the capacity of an arbitrarily selected winding relative to the housing before impregnation; $${\mathrm{FROM}}_{PP}^{*}$$

- the capacity of an arbitrarily selected winding relative to the housing after exposure to an impregnating liquid with a known dielectric constant until it completely fills the cavity of the winding; ε ₁ - dielectric constant of the impregnating liquid; ε ₂ - dielectric constant of the cured impregnating composition.

The disadvantage of the prototype method is the need for one of the arbitrarily selected windings to measure the capacitance relative to the casing before impregnation, then, after measuring the capacitance relative to the casing before impregnation, immerse the mentioned winding in an impregnating liquid with a known dielectric constant, and measure the capacitance of the winding relative to the casing without removing the winding from impregnating liquid. The introduction of this operation complicates the method.

In addition, the prototype method determines the average coefficient of impregnation of the windings, but in this way it is impossible to determine the distribution of the impregnating composition over the phases of the winding, which in most electrical machines is connected to a star with an insulated neutral, which reduces the information content and accuracy of the impregnation quality control.

The technical problem to which the invention is directed is to simplify the method, increase its information content and accuracy.

The stated technical problem is solved in that in the method for determining the coefficient of impregnation of the windings of electric machines, which characterizes the degree of filling with the impregnating composition of the cavities of the winding, in which each winding from this batch measures the electrical parameters before impregnation and after impregnation and drying, two capacitances are selected as electrical parameters phase windings connected in star, which are alternately measured before impregnation C _dp12, C _dp13, C _dp23, and C after it _{pp12, pp13} C, C _pp23 relative to the housing, after which the results athame measurements determine the coefficient of impregnation K of each two phases _{pr12, pr13} K, K _pr23 the formulas

$${\mathrm{TO}}_{\mathrm{<figure-callout\; id="12"\; label="P\; R"\; filenames="00000079.png"\; state="\{\{state\}\}">P\; </figure-callout>}R12}=\frac{\mathrm{one}}{\ln {\epsilon }_{P\mathrm{from}}}\times \ln \frac{{\mathrm{FROM}}_{PP12}({\mathrm{FROM}}_{\mathrm{uh}\mathrm{to}\mathrm{at}}-{\mathrm{FROM}}_{dP12})}{{\mathrm{FROM}}_{dP12}({\mathrm{FROM}}_{\mathrm{uh}\mathrm{to}\mathrm{at}}-{\mathrm{FROM}}_{PP12})},(3)$$

$${\mathrm{TO}}_{\mathrm{<figure-callout\; id="13"\; label="P\; R"\; filenames="00000079.png"\; state="\{\{state\}\}">P\; </figure-callout>}R13}=\frac{\mathrm{one}}{\ln {\epsilon }_{P\mathrm{from}}}\times \ln \frac{{\mathrm{FROM}}_{PP13}({\mathrm{FROM}}_{\mathrm{uh}\mathrm{to}\mathrm{at}}-{\mathrm{FROM}}_{dP13})}{{\mathrm{FROM}}_{dP13}({\mathrm{FROM}}_{\mathrm{uh}\mathrm{to}\mathrm{at}}-{\mathrm{FROM}}_{PP13})},(\mathrm{four})$$

$${\mathrm{TO}}_{PR23}=\frac{\mathrm{one}}{\ln {\epsilon }_{P\mathrm{from}}}\times \ln \frac{{\mathrm{FROM}}_{PP23}({\mathrm{FROM}}_{\mathrm{uh}\mathrm{to}\mathrm{at}}-{\mathrm{FROM}}_{dP23})}{{\mathrm{FROM}}_{dP23}({\mathrm{FROM}}_{\mathrm{uh}\mathrm{to}\mathrm{at}}-{\mathrm{FROM}}_{PP23})},(5)$$

- эквивалентная емкость последовательно соединенных емкостей эмали и корпусной изоляции двух фаз обмотки, p - количество пазов в магнитном сердечнике; S - площадь паза; ε₀=8,854187·10^-12 - электрическая постоянная; ε_э - диэлектрическая проницаемость эмалевой пленки провода обмотки; ε_к - диэлектрическая проницаемость корпусной изоляции; d_э - толщина эмалевой изоляции провода; d_к - толщина корпусной изоляции провода. После чего определяют коэффициенты пропитки каждой фазы обмотки по формуламWhere $${\mathrm{FROM}}_{\mathrm{uh}\mathrm{to}\mathrm{at}}=\frac{2pS{\epsilon }_0{\epsilon }_{\mathrm{uh}}{\epsilon }_{\mathrm{to}}}{3(d_{\mathrm{uh}}{\epsilon }_{\mathrm{to}}+d_{\mathrm{to}}{\epsilon }_{\mathrm{uh}})}(6)$$

- equivalent capacity of series-connected containers of enamel and case insulation of two phases of the winding, p is the number of grooves in the magnetic core; S is the area of the groove; ε ₀ = 8.854187 · 10 ^-12 is the electric constant; ε _e is the dielectric constant of the enamel film of the winding wire; ε _to - dielectric constant of the housing insulation; d _e - the thickness of the enamel insulation of the wire; d _to - the thickness of the shell insulation of the wire. Then determine the coefficients of impregnation of each phase of the winding according to the formulas

$${\mathrm{TO}}_{PR\mathrm{one}}={\mathrm{TO}}_{PR12}-{\mathrm{TO}}_{PR23}+{\mathrm{TO}}_{\mathrm{<figure-callout\; id="13"\; label="P\; R"\; filenames="00000079.png"\; state="\{\{state\}\}">P\; </figure-callout>}R13},(7)$$

$${\mathrm{TO}}_{PR2}={\mathrm{TO}}_{PR23}-{\mathrm{TO}}_{\mathrm{<figure-callout\; id="13"\; label="P\; R"\; filenames="00000079.png"\; state="\{\{state\}\}">P\; </figure-callout>}R13}+{\mathrm{TO}}_{\mathrm{<figure-callout\; id="12"\; label="P\; R"\; filenames="00000079.png"\; state="\{\{state\}\}">P\; </figure-callout>}R12},(8)$$

$${\mathrm{TO}}_{PR3}={\mathrm{TO}}_{PR13}-{\mathrm{TO}}_{\mathrm{<figure-callout\; id="12"\; label="P\; R"\; filenames="00000079.png"\; state="\{\{state\}\}">P\; </figure-callout>}R12}+{\mathrm{TO}}_{PR23},(9)$$

where K _CR1 , K _CR2 , K _CR3 - the coefficients of impregnation of the 1st, 2nd, 3rd phases, respectively.

In Fig 1. schematically shows the winding of a three-phase electric machine connected by a star with an insulated neutral. Positions 1, 2, 3 indicate the conclusions of the phases of the winding, position 4 indicates the neutral of the winding.

Figure 2 presents the cross section of the winding in one of the grooves, representing a layered system.

It consists of the wires of the winding 5, coated with a layer of enamel 6, the housing insulation 7, the surface of the groove 8, the air cavities between the surface of the winding and the housing insulation 9 and the air cavities between the housing insulation and the surface of the groove 10, the magnetic core (housing) 11.

Figure 3 shows the capacitance of the winding relative to the housing, which is the magnetic core of the stator of the electric machine, presented in the form of a layered flat capacitor before impregnation (Fig.3, A) and after it (Fig.3, B). In Fig. 3, A and Fig. 3, B, the same designations are introduced, only in Fig. 3, B, positions 12 and 13 are entered instead of positions 9 and 10, since the air cavities of the windings 9 and 10 after impregnation and drying are partially filled with impregnation composition. In connection with this, positions 12 and 13 indicate the same layers 9 and 10, but filled with particles of the impregnating composition statistically distributed over these layers. Figure 1, figure 2 and figure 3 serve to explain the essence of the invention.

The essence of the method is as follows.

The windings of three-phase electric machines are usually connected by a star (see figure 1).

In the prototype method, the conclusions of phases 1, 2, 3 are interconnected and, before impregnation, measure the capacitance of the winding Sdp relative to the magnetic core. After impregnation and drying of the winding, the leads 1, 2, 3 are again connected to each other and the capacitance of the winding SPn is measured. Then, according to the formula (2), using the results of all measurements described in the prototype method, the integrated average winding impregnation coefficient is determined. Meanwhile, the quality of the impregnation is evaluated not only by this averaged integral impregnation coefficient, but also by how evenly the impregnation composition is distributed over the winding cavities.

The winding of the electric machine, placed in the grooves of the magnetic core, is a layered system (see figure 1). Since the thickness d _{e of the} enamel insulation 6 of the wire 5, the thickness d _{to the} housing insulation 7, and the total thickness d _{in the} air cavities between the surface of the winding and the housing insulation 9 and the air cavities between the housing insulation and the surface of the groove 10 are negligible and are several microns, then the capacity of the winding relative to the housing can be neglected in the form of a layered flat capacitor (see figure 3). If you connect the terminals of phases 1 and 2 to each other before impregnation (Fig. 1) and measure the capacitance of these two phases relative to the magnetic core before impregnation With _dp12 , then repeat the same procedure with conclusions 1-3 and 2-3 and measure until the container is impregnated of the two corresponding phases C _dp13 and C _dp23 , then these containers, since they are connected in series, can be written, in accordance with figure 2, in the form of the following ratios:

$$\frac{\mathrm{one}}{{\mathrm{FROM}}_{\mathrm{<figure-callout\; id="12"\; label="d\; P"\; filenames="00000079.png"\; state="\{\{state\}\}">d\; </figure-callout>}P12}}=\frac{\mathrm{one}}{{\mathrm{FROM}}_{\mathrm{uh}12}}+\frac{\mathrm{one}}{{\mathrm{FROM}}_{\mathrm{to}12}}+\frac{\mathrm{one}}{{\mathrm{FROM}}_{\mathrm{at}12}},(10)$$

$$\frac{\mathrm{one}}{{\mathrm{FROM}}_{\mathrm{<figure-callout\; id="13"\; label="d\; P"\; filenames="00000079.png"\; state="\{\{state\}\}">d\; </figure-callout>}P13}}=\frac{\mathrm{one}}{{\mathrm{FROM}}_{\mathrm{uh}13}}+\frac{\mathrm{one}}{{\mathrm{FROM}}_{\mathrm{to}13}}+\frac{\mathrm{one}}{{\mathrm{FROM}}_{\mathrm{at}13}},(13)$$

$$\frac{\mathrm{one}}{{\mathrm{FROM}}_{dP23}}=\frac{\mathrm{one}}{{\mathrm{FROM}}_{\mathrm{uh}23}}+\frac{\mathrm{one}}{{\mathrm{FROM}}_{\mathrm{to}23}}+\frac{\mathrm{one}}{{\mathrm{FROM}}_{\mathrm{at}23}},(12)$$

where C _e12 , C _e13 , C _e23 are the capacities of the enamel insulation layer in two phases 1-2, 1-3, 2-3, respectively, C _k12 , C _k13 , C _k23 are the capacities of the layer of shell insulation in two phases 1-2 , 1-3, 2-3, respectively, C _b12 , C _b13 , C _b23 — the total capacities of the air layers 9 and 10 (Fig. 3) in two phases 1-2, 1-3, 2-3, respectively.

Since the type of windings of the same type have the same number of grooves in which the two phases of the winding are located, the groove area, the thickness d _e enamel and the thickness of the housing d _{to the} insulation are the same, it should be assumed that C _e12 = C _e13 = C _e23 = C _e (13) and C _k12 = C _k13 = C _k23 = Ck (14).

Considering relations (13) and (14), expressions (10), (11) and (12) can be rewritten in the form

$$\frac{\mathrm{one}}{{\mathrm{FROM}}_{\mathrm{<figure-callout\; id="12"\; label="d\; P"\; filenames="00000079.png"\; state="\{\{state\}\}">d\; </figure-callout>}P12}}=\frac{\mathrm{one}}{{\mathrm{FROM}}_{\mathrm{uh}}}+\frac{\mathrm{one}}{{\mathrm{FROM}}_{\mathrm{to}}}+\frac{\mathrm{one}}{{\mathrm{FROM}}_{\mathrm{at}12}},(\mathrm{fifteen})$$

$$\frac{\mathrm{one}}{{\mathrm{FROM}}_{\mathrm{<figure-callout\; id="13"\; label="d\; P"\; filenames="00000079.png"\; state="\{\{state\}\}">d\; </figure-callout>}P13}}=\frac{\mathrm{one}}{{\mathrm{FROM}}_{\mathrm{uh}}}+\frac{\mathrm{one}}{{\mathrm{FROM}}_{\mathrm{to}}}+\frac{\mathrm{one}}{{\mathrm{FROM}}_{\mathrm{at}13}},(16)$$

$$\frac{\mathrm{one}}{{\mathrm{FROM}}_{dP23}}=\frac{\mathrm{one}}{{\mathrm{FROM}}_{\mathrm{uh}}}+\frac{\mathrm{one}}{{\mathrm{FROM}}_{\mathrm{to}}}+\frac{\mathrm{one}}{{\mathrm{FROM}}_{\mathrm{at}23}}(17)$$

For a flat capacitor, you can write

$${\mathrm{FROM}}_{\mathrm{uh}}=\frac{2}{3}R\times \frac{{\epsilon }_0{\epsilon }_{\mathrm{uh}}S}{d_{\mathrm{uh}}}(\mathrm{eighteen})$$

$${\mathrm{FROM}}_{\mathrm{to}}=\frac{2}{3}R\times \frac{{\epsilon }_0{\epsilon }_{\mathrm{to}}S}{d_{\mathrm{to}}}(19)$$

$${\mathrm{FROM}}_{\mathrm{at}12}=\frac{2}{3}R\times \frac{{\epsilon }_0{\epsilon }_{\mathrm{at}}S}{d_{\mathrm{at}12}}(\mathrm{twenty})$$

$${\mathrm{FROM}}_{\mathrm{at}13}=\frac{2}{3}R\times \frac{{\epsilon }_0{\epsilon }_{\mathrm{at}}S}{d_{\mathrm{at}13}}(21)$$

$${\mathrm{FROM}}_{\mathrm{at}23}=\frac{2}{3}R\times \frac{{\epsilon }_0{\epsilon }_{\mathrm{at}}S}{d_{\mathrm{at}23}}(22)$$

where p is the number of grooves in the magnetic core of the stator, ε _e , ε _k , ε _in are the dielectric constant of enamel, housing insulation, air, respectively, ε ₀ = 8.854187817 · 10 ^-12 is the electric constant; With _B12 , C _B13 , C _B23 - the total capacity of the air layers 9 and 10 ( _figure 2) of the two phases 1-2, 1-3, 2-3, respectively. Substituting expressions (18), (19), (20), (21), (22) into formulas (15), (16), (17) and taking into account that the dielectric constant of air ε _in = 1, we can write

$$\frac{\mathrm{one}}{{\mathrm{<figure-callout\; id="12"\; label="FROM\; d\; P"\; filenames="00000079.png"\; state="\{\{state\}\}">FROM\; </figure-callout>}}_{dP}}=\frac{3d_{\mathrm{uh}}}{2R{\epsilon }_{\mathrm{uh}}{\epsilon }_{0}S}+\frac{3d_{\mathrm{to}}}{2R{\epsilon }_0{\epsilon }_{\mathrm{to}}S}+\frac{3{\mathrm{<figure-callout\; id="12"\; label="d"\; filenames="00000079.png"\; state="\{\{state\}\}">d</figure-callout>}}_{12}}{2R{\epsilon }_{0}S},(23)$$

$$\frac{\mathrm{one}}{{\mathrm{<figure-callout\; id="13"\; label="FROM\; d\; P"\; filenames="00000079.png"\; state="\{\{state\}\}">FROM\; </figure-callout>}}_{dP}}=\frac{3d_{\mathrm{uh}}}{2R{\epsilon }_0{\epsilon }_{\mathrm{uh}}S}+\frac{3d_{\mathrm{to}}}{2R{\epsilon }_0{\epsilon }_{\mathrm{to}}S}+\frac{3{\mathrm{<figure-callout\; id="13"\; label="d"\; filenames="00000079.png"\; state="\{\{state\}\}">d</figure-callout>}}_{13}}{2R{\epsilon }_{0}S},(24)$$

$$\frac{\mathrm{one}}{{\mathrm{FROM}}_{dP23}}=\frac{3d_{\mathrm{uh}}}{2R{\epsilon }_0{\epsilon }_{\mathrm{uh}}S}+\frac{3d_{\mathrm{to}}}{2R{\epsilon }_0{\epsilon }_{\mathrm{to}}S}+\frac{3d_{23}}{2{\epsilon }_{0}RS},(25)$$

From the expressions (23), (24) and (25) it follows

$$\begin{array}{l}{\mathrm{<figure-callout\; id="12"\; label="d"\; filenames="00000079.png"\; state="\{\{state\}\}">d</figure-callout>}}_{12}=\frac{2}{3}RS{\epsilon }_0(\frac{\mathrm{one}}{{\mathrm{FROM}}_{dP12}}-\frac{3d_{\mathrm{uh}}}{2R{\epsilon }_0{\epsilon }_{\mathrm{uh}}S}-\frac{3d_{\mathrm{to}}}{2R{\epsilon }_0{\epsilon }_{\mathrm{to}}S})=\\ =\frac{2}{3}\frac{{\epsilon }_{0}RS}{{\mathrm{FROM}}_{dP12}}-\frac{d_{\mathrm{uh}}}{{\epsilon }_{\mathrm{uh}}}-\frac{d_{\mathrm{to}}}{{\epsilon }_{\mathrm{to}}}=\frac{2RS{\epsilon }_0{\epsilon }_{\mathrm{uh}}{\epsilon }_{\mathrm{to}}-3{\mathrm{FROM}}_{dP12}(d_{\mathrm{uh}}{\epsilon }_{\mathrm{to}}+d_{\mathrm{to}}{\epsilon }_{\mathrm{uh}})}{3{\epsilon }_{\mathrm{uh}}{\epsilon }_{\mathrm{to}}{\mathrm{FROM}}_{\mathrm{<figure-callout\; id="12"\; label="d\; P"\; filenames="00000079.png"\; state="\{\{state\}\}">d\; </figure-callout>}P12}},(26)\end{array}$$

$${\mathrm{<figure-callout\; id="13"\; label="d"\; filenames="00000079.png"\; state="\{\{state\}\}">d</figure-callout>}}_{13}=\frac{2RS{\epsilon }_0{\epsilon }_{\mathrm{uh}}{\epsilon }_{\mathrm{to}}-3{\mathrm{FROM}}_{dP13}(d_{\mathrm{uh}}{\epsilon }_{\mathrm{to}}+d_{\mathrm{to}}{\epsilon }_{\mathrm{uh}})}{3{\epsilon }_{\mathrm{uh}}{\epsilon }_{\mathrm{to}}{\mathrm{FROM}}_{dP13}}(27)$$

$$d_{23}=\frac{2RS{\epsilon }_0{\epsilon }_{\mathrm{uh}}{\epsilon }_{\mathrm{to}}-3{\mathrm{FROM}}_{dP23}(d_{\mathrm{uh}}{\epsilon }_{\mathrm{to}}+d_{\mathrm{to}}{\epsilon }_{\mathrm{uh}})}{3{\epsilon }_{\mathrm{uh}}{\epsilon }_{\mathrm{to}}{\mathrm{FROM}}_{dP23}}(28)$$

After impregnation and drying of the windings, the volumes of the cavities 12 and 13 are partially filled with an impregnating composition having a dielectric constant ε _p (see Fig. 3, B). Since the impregnating composition does not completely fill the volumes of the cavities 12 and 13, but is statistically distributed over the cavities 12 and 13, a binary statistical mixture consisting of particles of the impregnating composition and air particles with a dielectric constant ε * is formed in the said cavities. The dielectric constant of the binary mixture ε * obeys the Lichtenecker-Rother distribution [3], according to which it can be written for phases 1-2 in the form

$$\mathrm{<figure-callout\; id="12"\; label="ln\; \epsilon "\; filenames="00000079.png"\; state="\{\{state\}\}">ln\; </figure-callout>}{\epsilon }_{}{}_{12}*=\frac{V_{P12}}{{\mathrm{<figure-callout\; id="12"\; label="V"\; filenames="00000079.png"\; state="\{\{state\}\}">V</figure-callout>}}_{12}}\ln {\epsilon }_P+\frac{V_{12}-V_{P12}}{{\mathrm{<figure-callout\; id="12"\; label="V"\; filenames="00000079.png"\; state="\{\{state\}\}">V</figure-callout>}}_{12}}\ln {\epsilon }_{\mathrm{at}}(\mathrm{29th})$$

where V _p12 is the volume occupied by the particles of the impregnating composition in layers 11 and 12,

V ₁₂ -V _p12 is the volume of air in layers 12 and 13, ε ₁₂ * is the dielectric constant of the statistical mixture in layers 12 and 13 of phases 1-2.

Given that the dielectric constant of air ε _in = 1, and lnε _in = 0, expression (29) can be written in the form

$$\mathrm{<figure-callout\; id="12"\; label="ln\; \epsilon "\; filenames="00000079.png"\; state="\{\{state\}\}">ln\; </figure-callout>}{\epsilon }_{}{}_{12}*=\frac{V_{P12}}{{\mathrm{<figure-callout\; id="12"\; label="V"\; filenames="00000079.png"\; state="\{\{state\}\}">V</figure-callout>}}_{12}}\ln {\epsilon }_P=={\mathrm{TO}}_{\mathrm{<figure-callout\; id="12"\; label="P\; R"\; filenames="00000079.png"\; state="\{\{state\}\}">P\; </figure-callout>}R12}\ln {\epsilon }_P(\mathrm{thirty})$$

есть не что иное, как коэффициент пропитки K_пр12 объемов полостей фаз 1-2, характеризующий степень заполнения объема полостей V₁₂ пропиточным составом.In expression (30), the ratio $$\frac{V_{P12}}{{\mathrm{<figure-callout\; id="12"\; label="V"\; filenames="00000079.png"\; state="\{\{state\}\}">V</figure-callout>}}_{12}}$$

there is nothing other than the coefficient of impregnation K _CR12 volume of the cavities of phases 1-2, characterizing the degree of filling the volume of cavities V ₁₂ impregnating composition.

Similar expressions can be written for layers 12 and 13 (Fig. 3, B) for phases 1-3 and 2-3

$$\mathrm{<figure-callout\; id="13"\; label="ln\; \epsilon "\; filenames="00000079.png"\; state="\{\{state\}\}">ln\; </figure-callout>}{\epsilon }_{}{}_{13}*=\frac{V_{P13}}{{\mathrm{<figure-callout\; id="13"\; label="V"\; filenames="00000079.png"\; state="\{\{state\}\}">V</figure-callout>}}_{13}}\ln {\epsilon }_P={\mathrm{TO}}_{\mathrm{<figure-callout\; id="13"\; label="P\; R"\; filenames="00000079.png"\; state="\{\{state\}\}">P\; </figure-callout>}R13}\ln {\epsilon }_P(31)$$

$$\ln {\epsilon }_{23}*=\frac{V_{P23}}{V_{23}}\ln {\epsilon }_P={\mathrm{TO}}_{PR23}\ln {\epsilon }_P(32)$$

If after impregnation and drying, measure the capacitances C _pp12 , C _pp13 , C _{pp23 of the} two corresponding phases relative to the housing and take into account that the impregnation composition, whose dielectric constant ε _{p, was} statistically distributed over the gap volumes d ₁₂ , d ₁₃ , d ₂₃ , then the layer capacities 12 and 13 in the corresponding two phases can be represented by the expressions

$${\mathrm{FROM}}_{\mathrm{<figure-callout\; id="12"\; label="P"\; filenames="00000079.png"\; state="\{\{state\}\}">P</figure-callout>}12}=\frac{2}{3}R\times \frac{{\epsilon }_0\epsilon {*}_{12}S}{d_{\mathrm{at}12}}(33)$$

$${\mathrm{FROM}}_{\mathrm{<figure-callout\; id="13"\; label="P"\; filenames="00000079.png"\; state="\{\{state\}\}">P</figure-callout>}13}=\frac{2}{3}R\times \frac{{\epsilon }_0\epsilon {*}_{13}S}{d_{\mathrm{at}13}}(34)$$

$${\mathrm{FROM}}_{P23}=\frac{2}{3}R\times \frac{{\epsilon }_0\epsilon {*}_{23}S}{d_{\mathrm{at}23}}(35)$$

Substituting into the equations (15), (16) and (17) instead of C _b12 , C _b13 , C _{b23 the} values C _p12 , C _p13 , C _p23, we can write the expressions for the capacities C _pp12 , C _pp13 , C _pp23

$$\frac{\mathrm{one}}{{\mathrm{FROM}}_{\mathrm{<figure-callout\; id="12"\; label="P\; P"\; filenames="00000079.png"\; state="\{\{state\}\}">P\; </figure-callout>}P12}}=\frac{3d_{\mathrm{uh}}}{2R{\epsilon }_0{\epsilon }_{\mathrm{uh}}S}+\frac{3d_{\mathrm{to}}}{2R{\epsilon }_0{\epsilon }_{\mathrm{to}}S}+\frac{3{\mathrm{<figure-callout\; id="12"\; label="d"\; filenames="00000079.png"\; state="\{\{state\}\}">d</figure-callout>}}_{12}}{2R{\epsilon }_0\epsilon {*}_{12}S},(36)$$

$$\frac{\mathrm{one}}{{\mathrm{FROM}}_{\mathrm{<figure-callout\; id="13"\; label="P\; P"\; filenames="00000079.png"\; state="\{\{state\}\}">P\; </figure-callout>}P13}}=\frac{3d_{\mathrm{uh}}}{2R{\epsilon }_0{\epsilon }_{\mathrm{uh}}S}+\frac{3d_{\mathrm{to}}}{2R{\epsilon }_0{\epsilon }_{\mathrm{to}}S}+\frac{3{\mathrm{<figure-callout\; id="13"\; label="d"\; filenames="00000079.png"\; state="\{\{state\}\}">d</figure-callout>}}_{13}}{2R{\epsilon }_0\epsilon {*}_{13}S},(37)$$

$$\frac{\mathrm{one}}{{\mathrm{FROM}}_{PP23}}=\frac{3d_{\mathrm{uh}}}{2R{\epsilon }_0{\epsilon }_{\mathrm{uh}}S}+\frac{3d_{\mathrm{to}}}{2R{\epsilon }_0{\epsilon }_{\mathrm{to}}S}+\frac{3d_{23}}{2R{\epsilon }_0\epsilon {*}_{23}S},(38)$$

From relations (36), (37), (38) we express the gaps d ₁₂ , d ₁₃ , d ₂₃

$$\begin{array}{l}{\mathrm{<figure-callout\; id="12"\; label="d"\; filenames="00000079.png"\; state="\{\{state\}\}">d</figure-callout>}}_{12}=\frac{2}{3}R{\epsilon }_0\epsilon {*}_{12}S(\frac{\mathrm{one}}{{\mathrm{FROM}}_{PP12}}-\frac{3d_{\mathrm{uh}}}{2R{\epsilon }_0{\epsilon }_{\mathrm{uh}}S}-\frac{3d_{\mathrm{to}}}{2R{\epsilon }_0{\epsilon }_{\mathrm{to}}S})={\epsilon }_{{}_0}\epsilon {*}_{12}(\frac{2}{3}\frac{RS}{{\mathrm{FROM}}_{PP12}}-\frac{d_{\mathrm{uh}}}{{\epsilon }_0{\epsilon }_{\mathrm{uh}}}-\frac{d_{\mathrm{to}}}{{\epsilon }_0{\epsilon }_{\mathrm{to}}})=\\ =\epsilon {*}_{12}[\frac{2RS{\epsilon }_0{\epsilon }_{\mathrm{uh}}{\epsilon }_{\mathrm{to}}-3{\mathrm{FROM}}_{PP12}(d_{\mathrm{uh}}{\epsilon }_{\mathrm{to}}+d_{\mathrm{to}}{\epsilon }_{\mathrm{uh}})}{3{\epsilon }_{\mathrm{uh}}{\epsilon }_{\mathrm{to}}{\mathrm{FROM}}_{PP12}}],(39)\end{array}$$

$${\mathrm{<figure-callout\; id="13"\; label="d"\; filenames="00000079.png"\; state="\{\{state\}\}">d</figure-callout>}}_{13}=\epsilon {*}_{12}[\frac{2RS{\epsilon }_0{\epsilon }_{\mathrm{uh}}{\epsilon }_{\mathrm{to}}-3{\mathrm{FROM}}_{PP13}(d_{\mathrm{uh}}{\epsilon }_{\mathrm{to}}+d_{\mathrm{to}}{\epsilon }_{\mathrm{uh}})}{3{\epsilon }_{\mathrm{uh}}{\epsilon }_{\mathrm{to}}{\mathrm{FROM}}_{PP13}}](40)$$

$$d_{23}=\epsilon {*}_{12}[\frac{2RS{\epsilon }_0{\epsilon }_{\mathrm{uh}}{\epsilon }_{\mathrm{to}}-3{\mathrm{FROM}}_{PP23}(d_{\mathrm{uh}}{\epsilon }_{\mathrm{to}}+d_{\mathrm{to}}{\epsilon }_{\mathrm{uh}})}{3{\epsilon }_{\mathrm{uh}}{\epsilon }_{\mathrm{to}}{\mathrm{FROM}}_{PP23}}](41)$$

Since after impregnation and drying, the gaps d ₁₂ , d ₁₃ , d ₂₃ in the controlled winding have not changed, we can equate the right sides of expressions (26), (27), (28) to the right parts of the corresponding expressions (39), (40) , (41), we obtain

$$\epsilon {*}_{12}[\frac{2RS{\epsilon }_0{\epsilon }_{\mathrm{uh}}{\epsilon }_{\mathrm{to}}-3{\mathrm{FROM}}_{PP12}(d_{\mathrm{uh}}{\epsilon }_{\mathrm{to}}+d_{\mathrm{to}}{\epsilon }_{\mathrm{uh}})}{3{\epsilon }_{\mathrm{uh}}{\epsilon }_{\mathrm{to}}{\mathrm{FROM}}_{PP12}}]=\frac{2RS{\epsilon }_0{\epsilon }_{\mathrm{uh}}{\epsilon }_{\mathrm{to}}-3{\mathrm{FROM}}_{dP12}(d_{\mathrm{uh}}{\epsilon }_{\mathrm{to}}+d_{\mathrm{to}}{\epsilon }_{\mathrm{uh}})}{3{\epsilon }_{\mathrm{uh}}{\epsilon }_{\mathrm{to}}{\mathrm{FROM}}_{dP12}}(42)$$

$$\epsilon {*}_{12}[\frac{2RS{\epsilon }_0{\epsilon }_{\mathrm{uh}}{\epsilon }_{\mathrm{to}}-3{\mathrm{FROM}}_{PP13}(d_{\mathrm{uh}}{\epsilon }_{\mathrm{to}}+d_{\mathrm{to}}{\epsilon }_{\mathrm{uh}})}{3{\epsilon }_{\mathrm{uh}}{\epsilon }_{\mathrm{to}}{\mathrm{FROM}}_{PP13}}]=\frac{2RS{\epsilon }_0{\epsilon }_{\mathrm{uh}}{\epsilon }_{\mathrm{to}}-3{\mathrm{FROM}}_{dP13}(d_{\mathrm{uh}}{\epsilon }_{\mathrm{to}}+d_{\mathrm{to}}{\epsilon }_{\mathrm{uh}})}{3{\epsilon }_{\mathrm{uh}}{\epsilon }_{\mathrm{to}}{\mathrm{FROM}}_{dP13}}(43)$$

$$\epsilon {*}_{12}[\frac{2RS{\epsilon }_0{\epsilon }_{\mathrm{uh}}{\epsilon }_{\mathrm{to}}-3{\mathrm{FROM}}_{PP23}(d_{\mathrm{uh}}{\epsilon }_{\mathrm{to}}+d_{\mathrm{to}}{\epsilon }_{\mathrm{uh}})}{3{\epsilon }_{\mathrm{uh}}{\epsilon }_{\mathrm{to}}{\mathrm{FROM}}_{PP23}}]=\frac{2RS{\epsilon }_0{\epsilon }_{\mathrm{uh}}{\epsilon }_{\mathrm{to}}-3{\mathrm{FROM}}_{dP23}(d_{\mathrm{uh}}{\epsilon }_{\mathrm{to}}+d_{\mathrm{to}}{\epsilon }_{\mathrm{uh}})}{3{\epsilon }_{\mathrm{uh}}{\epsilon }_{\mathrm{to}}{\mathrm{FROM}}_{dP23}}(44)$$

, $${\epsilon }_{13}*$$

, $${\epsilon }_{23}*$$

и, преобразовав полученные выражения, запишемFrom relations (42), (43), (44) we express $${\mathrm{<figure-callout\; id="12"\; label="\epsilon "\; filenames="00000079.png"\; state="\{\{state\}\}">\epsilon </figure-callout>}}_{12}*$$

, $${\epsilon }_{13}*$$

, $${\epsilon }_{23}*$$

and transforming the resulting expressions, we write

$${\mathrm{<figure-callout\; id="12"\; label="\epsilon "\; filenames="00000079.png"\; state="\{\{state\}\}">\epsilon </figure-callout>}}_{12}*=\frac{{\mathrm{FROM}}_{PP12}({\mathrm{FROM}}_{\mathrm{uh}\mathrm{to}\mathrm{at}}-{\mathrm{FROM}}_{dP12})}{{\mathrm{FROM}}_{dP12}({\mathrm{FROM}}_{\mathrm{uh}\mathrm{to}\mathrm{at}}-{\mathrm{FROM}}_{dP12})}(45)$$

$${\mathrm{<figure-callout\; id="13"\; label="\epsilon "\; filenames="00000079.png"\; state="\{\{state\}\}">\epsilon </figure-callout>}}_{13}*=\frac{{\mathrm{FROM}}_{PP13}({\mathrm{FROM}}_{\mathrm{uh}\mathrm{to}\mathrm{at}}-{\mathrm{FROM}}_{dP13})}{{\mathrm{FROM}}_{dP13}({\mathrm{FROM}}_{\mathrm{uh}\mathrm{to}\mathrm{at}}-{\mathrm{FROM}}_{PP13})}(46)$$

$${\epsilon }_{23}*=\frac{{\mathrm{FROM}}_{PP23}({\mathrm{FROM}}_{\mathrm{uh}\mathrm{to}\mathrm{at}}-{\mathrm{FROM}}_{dP23})}{{\mathrm{FROM}}_{dP23}({\mathrm{FROM}}_{\mathrm{uh}\mathrm{to}\mathrm{at}}-{\mathrm{FROM}}_{PP23})}(47)$$

- эквивалентная емкость последовательно соединенных емкостей эмали и корпусной изоляции.Where $${\mathrm{FROM}}_{\mathrm{uh}\mathrm{to}\mathrm{at}}=\frac{2RS{\epsilon }_0{\epsilon }_{\mathrm{uh}}{\epsilon }_{\mathrm{to}}}{3(d_{\mathrm{uh}}{\epsilon }_{\mathrm{to}}+d_{\mathrm{to}}{\epsilon }_{\mathrm{uh}})}(48)$$

- equivalent capacity of series-connected containers of enamel and case insulation.

We express from the relations (30), (31), (32) the impregnation coefficients K _CR12 , K _CR13 , K _{CR13 of the} corresponding phases 1-2, 1-3, 1 and 2-3, we obtain

$${\mathrm{TO}}_{\mathrm{<figure-callout\; id="12"\; label="P\; R"\; filenames="00000079.png"\; state="\{\{state\}\}">P\; </figure-callout>}R12}=\frac{\ln {\epsilon }_{12}*}{\ln {\epsilon }_P}(49)$$

$${\mathrm{TO}}_{\mathrm{<figure-callout\; id="13"\; label="P\; R"\; filenames="00000079.png"\; state="\{\{state\}\}">P\; </figure-callout>}R13}=\frac{\ln {\epsilon }_{13}*}{\ln {\epsilon }_P}(\mathrm{fifty})$$

$${\mathrm{TO}}_{PR23}=\frac{\ln {\epsilon }_{23}*}{\ln {\epsilon }_P}(51)$$

, $${\epsilon }_{13}*$$

, $${\epsilon }_{23}*$$

из соотношений (45), (46), (47), получимSubstituting in the expressions (49), (50) and (51) the values $${\epsilon }_{12}*$$

, $${\epsilon }_{13}*$$

, $${\epsilon }_{23}*$$

from relations (45), (46), (47), we obtain

$${\mathrm{TO}}_{\mathrm{<figure-callout\; id="12"\; label="P\; R"\; filenames="00000079.png"\; state="\{\{state\}\}">P\; </figure-callout>}R12}=\frac{\mathrm{one}}{\ln {\epsilon }_{P\mathrm{from}}}\times \ln \frac{{\mathrm{FROM}}_{PP12}({\mathrm{FROM}}_{\mathrm{uh}\mathrm{to}\mathrm{at}}-{\mathrm{FROM}}_{dP12})}{{\mathrm{FROM}}_{dP12}({\mathrm{FROM}}_{\mathrm{uh}\mathrm{to}\mathrm{at}}-{\mathrm{FROM}}_{PP12})}(52)$$

$${\mathrm{TO}}_{\mathrm{<figure-callout\; id="13"\; label="P\; R"\; filenames="00000079.png"\; state="\{\{state\}\}">P\; </figure-callout>}R13}=\frac{\mathrm{one}}{\ln {\epsilon }_{P\mathrm{from}}}\times \ln \frac{{\mathrm{FROM}}_{PP13}({\mathrm{FROM}}_{\mathrm{uh}\mathrm{to}\mathrm{at}}-{\mathrm{FROM}}_{dP13})}{{\mathrm{FROM}}_{dP13}({\mathrm{FROM}}_{\mathrm{uh}\mathrm{to}\mathrm{at}}-{\mathrm{FROM}}_{PP13})}(53)$$

$${\mathrm{TO}}_{PR23}=\frac{\mathrm{one}}{\ln {\epsilon }_{P\mathrm{from}}}\times \ln \frac{{\mathrm{FROM}}_{PP23}({\mathrm{FROM}}_{\mathrm{uh}\mathrm{to}\mathrm{at}}-{\mathrm{FROM}}_{dP23})}{{\mathrm{FROM}}_{dP23}({\mathrm{FROM}}_{\mathrm{uh}\mathrm{to}\mathrm{at}}-{\mathrm{FROM}}_{PP23})}(54)$$

The impregnation coefficients K _pr12 , K _pr13 , K _pr23 are the average statistical characteristic of the impregnation of the corresponding two phases, and their values can be determined from the expressions

$${\mathrm{TO}}_{\mathrm{<figure-callout\; id="12"\; label="P\; R"\; filenames="00000079.png"\; state="\{\{state\}\}">P\; </figure-callout>}R12}=\frac{{\mathrm{TO}}_{PR\mathrm{one}}+{\mathrm{TO}}_{PR2}}{2}(55)$$

$${\mathrm{TO}}_{\mathrm{<figure-callout\; id="13"\; label="P\; R"\; filenames="00000079.png"\; state="\{\{state\}\}">P\; </figure-callout>}R13}=\frac{{\mathrm{TO}}_{PR\mathrm{one}}+{\mathrm{TO}}_{PR3}}{2}(56)$$

$${\mathrm{TO}}_{PR23}=\frac{{\mathrm{TO}}_{PR3}+{\mathrm{TO}}_{PR2}}{2}(57)$$

where K _CR1 , K _CR2 , K _CR3 - the coefficients of the impregnation of phases 1, 2 and 3.

Having solved the system of equations (55), (56), (57), with respect to the phase impregnation coefficients K _CR1 , K _CR2 , K _CR3 , we obtain

$${\mathrm{TO}}_{PR\mathrm{one}}={\mathrm{TO}}_{PR12}-{\mathrm{TO}}_{PR23}+{\mathrm{TO}}_{PR13}(58)$$

$${\mathrm{TO}}_{PR2}={\mathrm{TO}}_{PR23}-{\mathrm{<figure-callout\; id="13"\; label="TO\; P\; R"\; filenames="00000079.png"\; state="\{\{state\}\}">TO\; </figure-callout>}}_{PR}+{\mathrm{TO}}_{PR12}(59)$$

$${\mathrm{TO}}_{PR3}={\mathrm{TO}}_{PR13}-{\mathrm{<figure-callout\; id="12"\; label="TO\; P\; R"\; filenames="00000079.png"\; state="\{\{state\}\}">TO\; </figure-callout>}}_{PR}+{\mathrm{TO}}_{PR23}(60)$$

where C _dp , C _pp - winding capacitance relative to the housing, respectively, before impregnation Example. The determination of the coefficients of impregnation of the windings of the stators of the asynchronous electric motor type 4A112M by the prototype method and the claimed method. According to the prototype method, before the impregnation and after the impregnation, the capacitances of all three phases of the windings connected to a star were measured relative to the stator magnetic core at an electric field frequency f = 1000 Hz by the E2-12 bridge. The results of measurements of capacitances of arbitrarily selected windings before and after impregnation are shown in table 1.

Table 1 No pp one 2 3 four 5 6 7 8 9 10 C _dp , pF 2430 2475 2480 2425 2470 2440 2450 2450 2470 2490 With _pp , pF 4009 4087 3720 3370 3581 3782 2480 3381 3754 3361 CRC one 0.56 0.44 0.35 0.40 0.46 0.36 0.34 0.45 0.31

погружали в бинарную жидкость диоксан-вода с диэлектрической проницаемостью ε₁=2,23. У погруженной в жидкость обмотки измеряется емкость относительно статора. Она равна $${С}_{пп}^{*}=4009$$

. По результатам измерений обмотки №1 определяют отношениеRandomly selected stator No. 1 with $${\mathrm{FROM}}_{dP}^{*}=2430\text{pF}$$

immersed in a binary liquid dioxane-water with a dielectric constant ε ₁ = 2.23. For windings immersed in a liquid, capacitance relative to the stator is measured. She is equal $${\mathrm{FROM}}_{PP}^{*}=4009$$

. According to the measurement results of winding No. 1 determine the ratio

$${\mathrm{FROM}}_{PP}^{*}/{\mathrm{FROM}}_{dP}^{*}=1.65$$

The windings of the stators are impregnated with varnish KP-34 by the jet-drop method. After drying the windings at the polymerization temperature of the KP-34 compound equal to 160 ° C, the capacitances of the windings relative to the stator C _pp were measured. According to the measurement results of the stator winding No. 1 and the controlled stator windings, the winding impregnation coefficients are determined by the expression (2)

$$\mathrm{TO}PR=\frac{\mathrm{one}}{\ln {\epsilon }_2}\ln \frac{{\epsilon }_{\mathrm{one}}{\mathrm{FROM}}_{PP}(\frac{{\mathrm{FROM}}_{PP}^{*}}{{\mathrm{FROM}}_{dP}^{*}}-\mathrm{one})}{\frac{{\mathrm{FROM}}_{PP}^{*}}{{\mathrm{FROM}}_{dP}^{*}}{\mathrm{FROM}}_{dP}({\epsilon }_{\mathrm{one}}-\mathrm{one})-{\mathrm{FROM}}_{PP}({\epsilon }_{\mathrm{one}}-\frac{{\mathrm{FROM}}_{PP}^{*}}{{\mathrm{FROM}}_{dP}^{*}})}$$

The dielectric constant of the cured impregnating compound KP-34 is ε ₂ = ε _p = 4,2.

At the same time, according to the claimed method, the impregnation coefficients of the respective two phases K _pr12 , K _pr13 , K _{pr23 were} determined for the same windings using formulas (52), (53), (54), and then the impregnation coefficients of each of the phases K _pr1 , K _pr2 , K _pr3 , using expressions (58), (59) and (60).

Preliminarily, from the expression (6), the value of C _{equiv was} determined based on the following winding data:

p = 36; S = 0.5375 × 10 ^-2 m ² ; d _e = 0.7 × 10 ^-3 m; d _k = 1 × 10 ^-3 m; ε _e = 3.85; ε _k = 5.92

$${\mathrm{FROM}}_{\mathrm{uh}\mathrm{to}\mathrm{at}}=\frac{2RS{\epsilon }_0{\epsilon }_{\mathrm{uh}}{\epsilon }_{\mathrm{to}}}{3(d_{\mathrm{uh}}{\epsilon }_{\mathrm{to}}+d_{\mathrm{to}}{\epsilon }_{\mathrm{uh}})}=\frac{2\times 36\times \mathrm{1,402}\times {10}^{-2}\times \mathrm{8,854187817}\cdot {10}^{-2}\times 3.85\times 5.92}{\mathrm{23,982}\times {10}^{-3}}=8493.78\text{pF}$$

The experimental values necessary to determine the coefficients of impregnation, and the results of the control by the present method are listed in table 2.

table 2 No pp one 2 3 four 5 6 7 8 9 10 With _dp12 , pF 1600 1620 1660 1590 1630 1600 1590 1670 1610 1650 With _dp13 , pF 1590 1650 1640 1630 1620 1630 1630 1600 1650 1640 S _dp23 , pF 1620 1640 1625 1610 1600 1670 1640 1650 1680 1650 C _pp12 , pF 2897 2557 2642 2771 2372 2773 2173 2626 2649 2364 C _pp13 , pF 2882 2972 2615 2653 2433 2679 2394 2558 2681 2514 C _pp23 , pF 2926 3356 2542 2513 2773 2657 2639 2740 2589 2446 K _pr12 one 0.42 0.43 0.47 0.34 0.51 0.28 0.42 0.46 0.33 K _pr13 one 0.56 0.43 0.45 0.37 0.46 0.35 0.45 0.45 0.39 K _pr23 one 0.7 0.41 0.42 0.51 0.43 0.44 0.47 0.40 0.36 K _pr1 one 0.28 0.45 0.50 0.20 0.54 0.19 0.40 0.51 0.36 K _pr2 one 0.56 0.41 0.44 0.48 0.48 0.37 0.44 0.41 0.30 K _pr3 one 0.84 0.41 0.40 0.54 0.38 0.51 0.50 0.39 0.42

From a comparison of the results shown in table 1 and the results shown in table 2, we can draw the following conclusions.

Simulation of 100% impregnation by immersion of the winding No. 1 in an inviscid liquid both by the prototype method and by the claimed method gives the same results, showing that in the winding No. 1, the pores and capillaries were completely filled with impregnating liquid. As follows from table 1, the winding No. 2 has the highest impregnation coefficient among all windings of the party, which in accordance with the prototype method is 0.56.

At the same time, according to the claimed method, the winding No. 2 has the largest uneven distribution of the impregnating composition and in phase 1 one of the lowest impregnation coefficients is observed, equal to 0.28. Since the reliability of the winding is determined by the weakest link, a low impregnation coefficient of 0.28 in phase 1 of the winding indicates a poor quality of the winding. The windings No. 3, No. 4 and No. 8 are most impregnated, as follows from Table 2, since the impregnating composition in these windings is evenly distributed over the phases of the winding, and the phase impregnation coefficients of these windings are high.

Thus, the claimed method in comparison with the prototype method has the following advantages.

In the inventive method, the operations present in the prototype method are eliminated: immersion of one of the batches of controlled windings in an inviscid liquid with a known dielectric constant, measurement of the capacitance of this winding relative to the housing before and after immersion, and the procedure for calculating the ratio of capacitances of an immersed winding to the capacitance of the same windings before immersion, which simplifies the inventive method.

In the inventive method, it became possible to determine not only the average coefficient of impregnation, but also the distribution of the impregnating composition over the phases of the winding, which compared with the prototype method significantly increases the information content and accuracy of the control.

List of references

1. Kondratyev N. G. et al. Evaluation of the possibility of using the electric capacity of the stator winding to control the quality of impregnation of the stators of low voltage electric motors. - Electrical industry. Series "Electric Machines", vol. 5/75, 1977.

2. A.S. No. 1241361. The method of determining the coefficient of impregnation of the windings of electric machines / GV Smirnov, GG Zinoviev. - Publ. 06/30/86. Bull. No. 24 is a prototype.

3. Smirnov G.V. Reliability of insulation of windings of electrical products. - Tomsk: Publishing house Tom. un-that. 1990. - p. 131.

Claims (1)

A method for determining the coefficient of impregnation of the windings of electric machines, characterizing the degree of filling with the impregnating composition of the cavities of the winding, in which each winding from a given batch measures the electrical parameters before impregnation and after impregnation and drying, characterized in that the capacitance of the two phases of the winding connected a star, which are alternately measured before impregnation C _dp12, C _dp13, C _dp23, and C after impregnation _{pp12, pp13} C, C _pp23 relative to the housing, after which the results of measurements define coefficient of impregnation K of each two phases _{pr12, pr13} K, K _pr23 the formulas
$${\mathrm{TO}}_{PR12}=\frac{\mathrm{one}}{\ln {\epsilon }_{P\mathrm{from}}}\times \ln \frac{{\mathrm{FROM}}_{PP12}({\mathrm{FROM}}_{\mathrm{uh}\mathrm{to}\mathrm{at}}-{\mathrm{FROM}}_{dP12})}{{\mathrm{FROM}}_{dP12}({\mathrm{FROM}}_{\mathrm{uh}\mathrm{to}\mathrm{at}}-{\mathrm{FROM}}_{PP12})}$$

,
$${\mathrm{TO}}_{PR13}=\frac{\mathrm{one}}{\ln {\epsilon }_{P\mathrm{from}}}\times \ln \frac{{\mathrm{FROM}}_{PP13}({\mathrm{FROM}}_{\mathrm{uh}\mathrm{to}\mathrm{at}}-{\mathrm{FROM}}_{dP13})}{{\mathrm{FROM}}_{dP13}({\mathrm{FROM}}_{\mathrm{uh}\mathrm{to}\mathrm{at}}-{\mathrm{FROM}}_{PP13})}$$

,
$${\mathrm{TO}}_{PR23}=\frac{\mathrm{one}}{\ln {\epsilon }_{P\mathrm{from}}}\times \ln \frac{{\mathrm{FROM}}_{PP23}({\mathrm{FROM}}_{\mathrm{uh}\mathrm{to}\mathrm{at}}-{\mathrm{FROM}}_{dP23})}{{\mathrm{FROM}}_{dP23}({\mathrm{FROM}}_{\mathrm{uh}\mathrm{to}\mathrm{at}}-{\mathrm{FROM}}_{PP23})}$$

,
Where $${\mathrm{FROM}}_{\mathrm{uh}\mathrm{to}\mathrm{at}}=\frac{2RS{\epsilon }_0{\epsilon }_{\mathrm{uh}}{\epsilon }_{\mathrm{to}}}{3(d_{\mathrm{uh}}{\epsilon }_{\mathrm{to}}+d_{\mathrm{to}}{\epsilon }_{\mathrm{uh}})}$$

- equivalent capacity of series-connected containers of enamel and case insulation of two phases of the winding, p is the number of grooves in the magnetic core; S is the area of the groove; ε ₀ = 8.854187 · 10 ^-12 is the electric constant; ε _e is the dielectric constant of the enamel film of the winding wire; ε _to - dielectric constant of the housing insulation; d _e - the thickness of the enamel insulation of the wire; d _to - the thickness of the housing insulation of the wire, and then determine the coefficients of impregnation of each phase of the winding according to the formulas
K _pr1 = K _pr12 -K _pr23 + K _pr13 ,
K _pr2 = K _pr23 -K _pr13 + K _pr12 ,
K _pr3 = K _pr13 -K _pr12 + K _pr23 ,
where K _CR1 , K _CR2 , K _CR3 - the coefficients of impregnation of the 1st, 2nd, 3rd phase, respectively.

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