JPS61254050A - Insulation treating method for stator for rotary electric machine - Google Patents

Abstract

PURPOSE:To improve periodic damping effect, by carrying out varnish impregnation treatment, first, with varnish of high solubility and permeability and low hardness, and by carring out the treatment, second, with varnish of high hardness. CONSTITUTION:The rotary shaft 5 of a rotor 4 is supported by a bracket 7 on the side of a stator frame 2 via bearings 6. A stator core 3 is wound up with windings 8. In a state that the stator core 3 is wound up with the windings 8, varnish impregnation treatment is carried out on the windings 8 twice. First, so far as the varnish used for varnish treatment is concerned, for example, rubber silicon varnish of high flexibilty and permeability and 50 or less of Shore hardness is used and is treated with coat of approx. 0.010mm in average in thickness. After that, on the second varnish treatment, for example, epoxy varnish of hardness higher than that for the first time and 200 or more for Shore hardness is used.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention uses direct electromagnetic forced external force to reduce vibration and noise when the natural frequency of the stator core of a rotating electric machine resonates with the frequency of electromagnetic force waves. The present invention relates to an insulating treatment method for a stator for a rotating electric machine, which reduces vibration and noise by providing a stator core with a large vibration damping effect.

[Technical background of the invention and its problems] AC motors are widely used because they can easily convert electrical energy into mechanical energy, and in recent years, inverters have been used to control the speed of various machines that use AC motors as a drive source. This is happening more and more often. However, in speed control using an inverter, voltage and current waveforms are distorted, magnetic flux harmonics are generated in the stator and rotor of the AC motor, and the electromagnetic force causes noise and noise. Furthermore, in electric motors with a fixed frequency, resonance with the frequency of the electromagnetic force wave was avoided by avoiding the natural frequency of the stator core, but this is difficult when controlling the speed using an inverter because the frequency is variable. be. Conventionally, as a means to absorb such vibrations, it has been considered to elastically support the stator core of the electric motor on the stator frame with elastic beams, but an elastic support material that effectively absorbs vibrations has not been available. It wasn't. In order to provide elastic support for this, it is necessary to use an elastic member, which increases the volume of the rotating electric machine itself.
The disadvantage is that the cost is considerably high due to increased material costs and manufacturing man-hours.

[Object of the Invention] The object of the present invention is to provide a method for insulating a stator for a rotating electric machine, which can reduce vibration and noise by imparting large vibration damping characteristics to a stator core that is directly subjected to an electromagnetic forced external force. It's about doing.

[Summary of the Invention] According to the present invention, the winding wire wound around the stator core is impregnated with varnish at least twice.
The first impregnation treatment uses a varnish with high flexibility and permeability, and the second impregnation treatment uses a varnish with higher hardness than the first one, which causes large vibrations in the stator core. It has damping characteristics and can be expected to have a fairly effective vibration and noise reduction effect.

I will explain. FIG. 1 shows an electric motor 1 to which the present invention is applied. In this Figure 1, 2 is the stator core 3
4 is a rotor, and this rotor 4
The rotating shaft 5 is connected to the stator frame 2 side bracket 7 via a bearing 6.
is supported by For example, a randomly wound winding 8 is wound around the stator core 3, and the coil end 8a protrudes relatively long due to the randomly wound winding. Specifically, as shown in FIG. 2, this roll 118 is housed in the slot 9 via a U-shaped slot insulator 10, and is prevented from escaping by a slot wedge 11.

The winding 8 is impregnated with varnish twice while being wound around the stator core 3 as described above. The varnish used in the first varnish treatment is a Shore hard varnish with high flexibility and permeability, however, it was tested using a Type A 2 tester.

The same applies hereinafter in this document) Using a rubber-based silicone varnish of 50 or less, for example, the film is treated to an average coating thickness of about 0.010 mm. After this, in the second varnish treatment, for example, an epoxy varnish having a Shore hardness of 200 or more, which is higher in hardness than the first varnish treatment, is used.

As a result of the above, since a low hardness varnish with high flexibility and permeability is used in the first varnish treatment, this varnish is applied between the laminated steel plates of the stator core 3, on the slot 9 surface, the slot insulator, and the winding 8. It penetrates sufficiently between the kings of and between the east wires of winding 8. Therefore, when an electromagnetic forced external force acts directly on the stator core 3 side, the varnish coating that has penetrated between all the members causes friction due to the relative displacement between the members via this coating, exerting a vibration damping effect.

FIG. 3 shows an example of measuring the vibration response characteristics of a single stator, with the horizontal axis representing the frequency λ and the vertical axis representing α/F (F is force and α is vibration acceleration). In this figure 3, (A)
-(C) are examples in which varnish impregnation treatment was performed only once, especially (A> is when the hardness of the varnish used is "low", and (B) is "
(C) shows the case of "High" (Shore hardness 50 or less), and (D) shows the case of varnish impregnation treatment with different hardness as in the above embodiment of the present invention. It also shows the case where it was done twice. As is clear from FIG. 3, it can be seen that a high vibration damping effect can be obtained by the insulation treatment method according to the present invention.

In order to achieve this, a special elastic part i is not required, and the volume of the electric motor 1 does not increase, so the manufacturing cost is reduced.

In particular, vibrations of electric motors that use variable frequency power sources such as inverters and have applications where resonance points are unavoidable.

Beneficial for noise reduction.

[Effects of the Invention] As described above, the present invention includes a varnish for stator windings. i
Provides a method for insulating a stator of a rotating electric machine that can be expected to have a high vibration damping effect by first applying a varnish that has high flexibility and permeability and low hardness, and then performing the second process using a varnish that is highly hard. can.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view of an electric motor in which the method of the present invention is implemented;
Figure 2 is an enlarged vertical sectional view along the n-5th line in Figure 1, and 3W.
A is a vibration response characteristic diagram of the stator. In the figure, 2 is a stator frame, 3 is a stator core, 4 is a rotor, and 8
is a winding. Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] 1. The windings wound around the stator core are impregnated with a flexible and highly permeable varnish with a Shore hardness of 50 or less, and then impregnated with a varnish with a Shore hardness of 200 or more. A method for insulating a stator for a rotating electric machine, characterized by: