JPH06141499A - Insulating method for winding of random winding insulated motor, and insulated winding - Google Patents

Abstract

PURPOSE:To provide a random winding insulated motor which has extremely high reliability by preventing the deterioration of insulation without being accompanied by the increase of the number of components increase in size. CONSTITUTION:In the method of insulating the winding of a random winding insulated motor being driven by an inverter, it is insulated so that the partial discharge start voltage (CVD) between the turns of the insulated cable of the winding 1 of a motor may be higher than the surge voltage generated at combined operation of the inverter and the motor. Moreover, as the insulated cable of the winding 1 of the random winding insulated motor, an insulated cable being provided, outside of an enamel layer, with an insulating layer of glass or high polymer material excellent in radiation resistance is used.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an insulation structure of a random winding insulation motor, and more particularly to a winding insulation method and an insulation winding of a random winding insulation motor which is driven by an inverter and which requires extremely high reliability for nuclear power applications. Regarding the line.

[0002]

2. Description of the Related Art An electric motor driven by an inverter is
Since the surge voltage generated at the time of switching the inverter is applied, it is necessary to prevent insulation failure due to the surge voltage. In particular, depending on the laying conditions of the power cable between the inverter and the electric motor, a steep surge having a rising speed of 1 microsecond or less occurs at the electric motor terminal. In this case, a surge voltage about twice the power supply voltage of the inverter may be generated.

According to a study conducted by the applicant of the present invention (1987 National Conference of the Institute of Electrical Engineers of Japan, reference 270), insulation deterioration due to surge voltage is considered to be mainly caused by discharge deterioration. That is, when the surge voltage enters the motor winding, an imbalance of the potential distribution occurs inside the winding, so that partial discharge occurs, insulation deterioration progresses, and eventually dielectric breakdown occurs. Therefore, as a method to ensure the reliability of insulation,
(1) A filter is attached to the motor terminal to reduce the surge voltage peak value, (2) Insulation is thickened, and mold winding insulation is used to increase the insulation reliability of the winding.
(3) It is considered to use a material having excellent partial discharge resistance such as mica as a coating material for the insulated wire.
In the method (1), since it is necessary to attach a filter to each phase, the number of parts may increase and reliability may decrease, which is not suitable for nuclear applications. In the case of (2), the possibility of contact between the first turn and the final turn of the coil is eliminated by adopting die winding insulation, but there is a problem that the application is limited because the coil becomes large. (3)
In this method, an electric wire for random winding insulation that can be practically used has not been developed yet. A slot liner is used in random winding insulation as an insulation reinforcement against the ground. For this reason,
If there is no problem in the reliability of the inter-turn insulation, the evaluation test of the ground insulation is unnecessary.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to reduce the reliability and increase the size of an electric motor due to an increase in the number of parts. An object of the present invention is to provide a winding insulation method and an insulated winding for an inverter-driven random winding insulation motor that prevents insulation deterioration and has extremely high reliability.

[0005]

In order to achieve the above-mentioned object, the present invention provides a winding insulation method for a random winding insulation motor driven by an inverter, wherein a partial discharge between insulated wire turns of the winding of the motor. Insulation is performed so that the starting voltage (CSV) is higher than the surge voltage generated during the combined operation of the inverter and the electric motor. As the insulated wire for the winding of the random winding insulation motor, an insulated wire in which an insulating layer made of glass or a polymer material excellent in radiation resistance is provided outside the enamel layer is used.

[0006]

With the above structure, the occurrence of partial discharge can be suppressed even when driven by an inverter, and a random winding insulation motor having extremely high insulation reliability can be obtained.
Further, it is excellent in radiation resistance, and a wound winding insulation motor for nuclear power application can be obtained.

[0007]

[Embodiment] Since the first turn and the last turn may come into contact with the random winding insulation coil of the random winding insulation motor, in consideration of the worst condition, the entire voltage shared by the coil should be applied between the turns. become. When the surge voltage enters the winding, the voltage shared by each coil depends on the coil position in the winding, and generally the first coil has a large share.
It is considered to be 60% to 70% of the inrush surge voltage.
Therefore, considering the intrusion surge voltage as the maximum voltage between turns, there is a margin of 30% to 40% under the worst conditions, so the partial discharge inception voltage between turns must be equal to or higher than the surge voltage generated during inverter operation. Therefore, it can be considered that partial discharge does not occur between turns. However, since the enameled wire used for random winding insulation has a thin insulating coating, the CSV often falls below this value when the intrusion surge voltage is high. Therefore, it is necessary to increase the wire spacing between turns. For this reason, in this embodiment, an insulating layer is provided by taping glass fiber or a polymer material having excellent radiation resistance on the outside of the enamel wire. Also, prepare the same model coil as the random winding insulation coil of the random winding insulation motor.

The model coil 1 shown in FIG. 1 is an example of a randomly wound model coil whose partial discharge inception voltage and dielectric breakdown voltage between turns can be measured under the most severe conditions. With this model coil, a voltage can be applied between the lead wires 2 of the leads.

[0009]

[Table 1]

The electric wire materials evaluated in the experiment were 0.9 mmφ enameled wire, 1.0 mmφ single glass wound enameled wire, and 1.2 mmφ enameled wire.
There are three types of mmφ double glass wound enamel wire. The coating thickness is 40 μm for the enamel layer, 60 μm and 110 μm for the glass layer, and the dielectric constant is 3.7 for the enamel layer and 4.0 for the glass layer. In order to make the conditions strict, the measurement was performed before the resin impregnation treatment. Table 1
Figure 3 shows the measurement results of the partial discharge inception voltage and the breakdown voltage between turns. The values in Table 1 are average values of 5 samples.

When the surge voltage was measured with the inverter and the motor combined, the surge voltage was Vp = 565.
It was V. Therefore, in this case, if the single glass winding enamel wire or the double glass winding enamel wire is selected as the wire material from the results of Table 1, partial discharge will not occur even when driven by an inverter.

As described above, by measuring the partial discharge inception voltage between turns under the most severe conditions and selecting the insulation configuration that exceeds the inverter surge voltage in the combined state of the inverter and the electric motor, the extremely reliable random winding insulation is achieved. An electric motor is obtained.

In order to confirm high reliability, 3 shown in Table 1
Model coil is made with various kinds of electric wires, 900 Vp, 1000H
A voltage applied life test was performed at z. As a result, the enamel wire
It was destroyed from 241h to 950h, but the glass coil had 31 coils.
No breakdown occurred even after 00 h, and the insulation breakdown voltage measured after the test was not lower than the initial value.

Although the case of the glass winding has been described as an example, a polymer material having excellent radiation resistance can be used instead of glass, and the glass fiber containing no boron can be used in a radiation environment. Is a suitable material, and a random winding insulation motor suitable for nuclear power applications is obtained. Further, in the embodiment, the partial discharge inception voltage between insulated wire turns and the inverter surge voltage in the state where the inverter and the electric motor are combined are obtained by actual measurement, but it goes without saying that they can be estimated by simulation or the like.

[0014]

According to the present invention, it is possible to prevent insulation deterioration without lowering reliability due to an increase in the number of parts and without enlarging the size of the motor, and it is possible to achieve extremely high reliability in the inverter-driven random winding. It is possible to obtain a winding insulating method for an insulated motor and an insulated winding.

[Brief description of drawings]

FIG. 1 shows an embodiment of a model coil of an insulated winding of a randomly wound insulation motor according to the present invention.

[Explanation of symbols]

 1 ... Model coil 2 ... Between lead wires

Claims (2)

[Claims] 1. A winding insulation method for a randomly wound insulation motor driven by an inverter, wherein a partial discharge inception voltage (CSV) between insulated wire turns of a winding of the motor is a surge generated during combined operation of the inverter and the motor. A winding insulation method for a random winding insulation motor, characterized in that insulation is performed so that the voltage becomes higher than the voltage. 2. An irregularly wound insulated electric motor, wherein an insulated electric wire having an insulating layer made of glass or a polymer material excellent in radiation resistance is provided on the outer side of an enamel layer as an insulated electric wire of a winding of the irregularly wound insulated motor. Isolated winding.