JPS63314151A - Coil of rotary electric machine - Google Patents

Abstract

PURPOSE:To enhance the coil insulating strength of an apparatus by inserting a coil with a phase to be on the outermost side, then placing a coil-end interphase paper, applying a slot insulation overlapping more than 1mm with said interphase paper, and thereafter inserting a second-phase coil. CONSTITUTION:After a slot insulation 3 has been inserted into a slot 2, a first- phase coil 4 to be inserted on the outermost side is housed therein and an interphase insulating paper 5 is placed in a coil-end part. Then, after a slot insulation 6 having a length overlapping at least 1mm with said interphase paper 5 has been inserted into said core slot, a second-phase coil 7 is housed therein. Also, a third phase coil is processed in like manner and inserted into a slot. Then, after coil ends have been bound with a thread and fixed, they are subjected to a varnish treatment and hardening. Thus, even if a deformation and slippage are generated in the interphase paper at the time of binding said coil ends with a thread and forming said coils, said slot insulation serves also as an insulation between different phases so that an interphase insulating strength can be enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Objective of the Invention (Industrial Application Field) The present invention relates to coil insulation of a motor whose rotation #J is controlled by a variable frequency power source.

(Prior Art) In recent years, the rotation of induction motors has been controlled by variable frequency power supplies, such as large-capacity inverter power supplies.

In this case, the induction motor and the inverter power source are generally connected by a long cable, for example, 10 m or more.

However, the inverter power source is a steep pulse chopped by DC voltage and semiconductor elements. especially,
Recent semiconductor devices have excellent switching performance, and the rise time of their output waveforms is as short as 1/10 microsecond (μS). For this reason, the long power cable becomes a distributed constant circuit, which is reflected at the motor connection terminal and causes so-called reflective resonance, and a voltage pulse approximately twice the power supply voltage is repeatedly applied to the motor terminal. Since this pulse voltage is generally called a surge, it will be simply referred to as a surge from now on. Another problem is that the motor winding is made up of multiple unit coils of several turns connected in series, so depending on the surge voltage rise speed mentioned earlier, the coil closest to the power supply terminal ( This is called the first coil), for example, with a rising speed of 0.2μ.
s, 80% of the previous surge voltage may be applied to this coil.

Therefore, there is a risk that the wire insulation coating of the coil may be destroyed by the above-mentioned surge, and in such a case, a coil burnout accident may occur. Conventionally, this has been countered by increasing the thickness of the wire insulation coating (for example, increasing the thickness of only the first coil) to increase the withstand voltage of the wire insulation.

(Problem to be solved by the invention) By increasing the coating thickness of the wire using conventional technology, it is possible to increase the dielectric strength in the first coil, thereby preventing dielectric breakdown within the first coil. be able to. but,
As a test method for evaluating the lifespan of electric motors, there is the IEEE Standard 117, which is a test method that is used as a film. In accordance with this standard, we used an inverter as a drive power source and connected a power cable of approximately 150 m to evaluate the heat resistance life.We found that the life was a few percent of the life when operated with a commercial type (abbreviated as AC). was found through experiments.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a coil for a motor whose rotation is controlled by a variable frequency power source, which can increase the coil insulation strength and improve workability due to the coil insulation.

[Structure of the Invention] (Means for Solving the Problems) The present invention relates to a coil of a rotating electric machine whose rotation is controlled by a variable frequency power source, for example, a three-phase concentrically wound coil. After inserting the outermost phase coil into the core slot, place a coil-end interphase paper, and then apply slot insulation having a length that overlaps at least one rhyme with this interphase paper to the stator core slot. Insert the matching coil. Similarly, the feature is that the third phase coil is inserted after insulating the phases and insulating the slots.

(Function) According to the present invention, between different phases (for example, U phase and W phase), even if the paper between the phases is deformed, the slot insulation becomes the different phase insulation due to the thread binding at the coil end, and the slot insulation becomes the different phase insulation. It is possible to ensure proof strength, and it becomes possible to use a variable frequency power supply in a low-cost and easy way.

(Embodiment) A first embodiment of the present invention will be described below with reference to FIGS. 1 and 2, using a three-phase concentrically wound coil as an example.

In Fig. 1, reference numeral 1 denotes a stator core of an induction motor that is variable frequency controlled.After inserting a slot insulator 3 into a slot 2 provided in this core, a first phase coil 4 to be inserted at the outermost side is housed, and the coil Place interphase insulating paper 5 on the end portion. Thereafter, a slot is formed that overlaps the co-phase interleaving paper 5 by at least 1 mm or more, and has a length sufficient to prevent the co-phase interleaving paper 5 from deforming or shifting its position by at least 1 mm due to coil end thread binding performed in a later process. Insert the insulation 6 into the corresponding core slot. After insulating in this way, the second phase coil 7
pay. Similarly to the second phase coil, the third phase coil is also installed so that the coil end interlayer paper and the slot insulation overlap by 1+im or more, and then the third phase coil is placed. The coil thus manufactured is tied and fixed at the end of the coil by the same method as in the prior art, and then treated with varnish and hardened.

With this slot insulation, even if the interphase paper is deformed or shifted during coil end thread tying or coil shaping, the slot insulation will also serve as insulation between different phases (for example, U phase and W phase). The insulation strength will be sufficient.

For this reason, coil end thread binding, which is a drawback of conventional technology,
It is possible to prevent a drop in withstand voltage between different phases due to paper misalignment during coil shaping, and as a result, it is possible to extend the life of the motor closer to that when operating at conventional commercial frequency (AC). be.

(Other Examples) As a second example, the first example did not mention the wire coating, but as shown in the prior art, the wire coating is thick (for example, the thickness of only the first coil). ) and the technology of the present invention, it is more effective in preventing burnout of the first coil when the surge voltage is distributed unequally within the coil, and it is possible to have the same lifespan as in AC operation. understood.

As a third embodiment, in the manufacturing procedure described in the first embodiment, the coil is generally packed with the first to third coarse coils and then the interlayer paper is inserted, but in the present invention, the coil This effect is fully demonstrated even in the procedure for inserting interleaving paper.

[Effects of the Invention] According to the present invention, it is possible to prevent a decrease in the dielectric strength between different phases due to paper shift between the phases at the coil ends, which is a drawback of the conventional technology, and to improve the coil rotation of an electric motor whose rotation is controlled by a variable frequency power source. It is possible to increase the insulation strength and prevent the occurrence of a coil burnout accident, and it is also possible to obtain the excellent effect of easily leveling the coil insulation.

[Brief explanation of the drawing]

Figures 1 to 2 show embodiments of the present invention.
FIG. 2 is a perspective view of the coil end, FIG. 2 is a sectional view of the intermediate portion, and FIG. 3 is a perspective view of a conventional coil end. In the figure, 1 is the stator core, 2 is the slot, 3.6 is the slot insulation, 4 is the first phase coil, 5 is the interphase paper, and 7 is the second phase coil. Agent Patent Attorney Nori Ken Yudo Ken Maru No. 2, Figure 3

Claims (2)

[Claims] (1) In the coil of a rotating electric machine whose rotation is controlled by a variable frequency power supply, the length of the slot insulator inserted into the slot of the stator core is such that it overlaps the interphase paper inserted between the phases of the different phase coil end portion by 1 mm or more, A coil for a rotating electrical machine in which the slot insulator inserted into the slot and the interlayer paper inserted between the coil end phase have a length such that the slot insulator and the interlayer paper are in abutment or overlap even after coil end thread binding or coil end shaping. (2) A coil for a rotating electrical machine as set forth in claim 1, wherein a coil is used in which the thickness of the insulating coating of the magnet wire used is increased for the coil closest to the power supply terminal than for other coils.