JP3706836B2 - How to regenerate old electrical equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for regenerating an insulating portion of a large-sized electric apparatus, particularly a rotating armature of a DC generator, which has been used for many years and has an endured life due to deterioration.
[0002]
[Prior art]
Currently, DC generators such as large generators manufactured during the high growth period are approaching the end of their service life after 30 years of operation. The life of these large DC machines is often determined by the deterioration of the insulating layer. However, many of the mechanical structural parts of this device can be used sufficiently even after 30 years. Therefore, it is desired to develop a new processing technique capable of extending the insulation life by restoring the insulation characteristics. Yes.
[0003]
[Problems to be Solved by the Invention]
On the other hand, in AC motors, taking into account the deterioration of insulation in aging machines, deaeration is performed in a vacuumed chamber, and then the entire varnish is immersed in the varnish so that the varnish is coiled. The method of impregnating the varnish as an insulating layer is used as a technique for prolonging the life, and this varnish soaking method has been successful in an AC machine.
[0004]
However, in the DC machine, this soaking method is not necessarily successful. The reason is that the armature coil of the DC machine has a “commutator”, so it is necessary to provide a lead-out part for drawing a large number of wires, even if the winding part is once impregnated in a vacuum atmosphere. This is because the varnish flows out in the drying process for curing the resin. This can be determined as described above because there is a portion where the varnish is not sufficiently spread when the armature impregnated with the varnish is disassembled.
[0005]
The first object of the present invention is to propose a method for more reliably impregnating and curing an insulating resin such as varnish to a withered insulating layer of an electrical equipment that has deteriorated over time as described above. It is an object of the present invention to provide a method for regenerating an aged electric device, particularly a rotating armature (rotor) insulating part, which can exert a leak-proofing action on the outlet portion that flows out and a more uniform varnish hardening action.
[0006]
[Means for solving the problems]
  In order to achieve the above object, the present invention provides a method for regenerating an aging electrical apparatus according to the present invention.
  1) A step of immersing a rotating armature whose insulating layer has deteriorated due to aging in a liquid insulating material under vacuum to impregnate the insulating layer with the insulating material;In the drying chamber whereWhile rotatingImpregnated with the insulating materialSolidify the insulating material to form a new insulating layerA method of regenerating an aging electrical equipment comprising a step, wherein the infrared radiation emitted from a ceramic layer on the inner surface of an electric heater of a local heating device provided so as to surround the commutator of the rotating armature The commutator portion of the rotary armature is locally heated, and the solidification of the insulating material in the commutator portion of the rotary armature is accelerated than the other portions.
[0007]
2)The heating device provided on the ceiling of the drying chamber heats the air in the drying chamber sucked from the air suction port of the warm air generating unit provided on the back side of the heater by the heater and discharges the air from the discharge port on the opposite side. Liquid insulation in which the rotary armature is impregnated by radiating far-infrared rays into the drying chamber from a ceramic layer laminated on a radiator plate provided on the drying chamber side of the heater, while being ejected as heated air into the drying chamber It is characterized by solidifying the material to form a new insulating layer.
[0012]
3) The ceramic layer is formed by plasma spraying ceramic powder on the surface of the heat radiating plate, and the ceramic layer is made of titanium oxide as the first layer on the surface side of the heat radiating plate, and the second layer thereon. It is characterized by being formed in a plurality of layers made of aluminum oxide.
[0013]
In short, the present invention relates to a method for regenerating an insulating part of a rotating armature of a large-sized rotating electrical machine equipment, particularly a DC generator, whose insulating part has become obsolete due to long-term use. After degassing, impregnate a liquid insulating material in the same atmosphere, and when it is heated and cured, use heated air and infrared radiation, and further cure the portion where this insulating material tends to flow out first Thus, a method for preventing the liquid insulating material from flowing out before being cured is provided.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Before explaining the details of the embodiment of the present invention, it will be explained from "basic experiment" such as a penetration test of a varnish which is an insulating material.
1. Surface tension of varnish and penetration test into gap
Coils for rotating electrical machines, not limited to DC machines, have a number of layers of insulation. Each layer of insulation is impregnated and cured with varnish on glass tape (or sheet) or mica glass tape (or sheet). It is composed.
[0015]
When the insulating layer is further deteriorated, the polymer constituting the resin is decomposed due to the thermal deterioration, and mechanical wear is also caused by the vibration of the coil. Therefore, it is considered that the strength between the layers of the insulating layer is weakened, and a separation is formed. This is clear even in the case where the coil is taken out from the electrical equipment after aged use and investigated, and the separation between the insulations of the coil is clear.
[0016]
Considering the thickness of the insulating layer and the number of insulating layers, it is considered that the gap generated due to the delamination between the insulating layers needs to be re-impregnated within 20 to 50 μm between one layer.
[0017]
Since the surface pressure of the brush pressure is constantly applied to the insulating layer of the armature coil in the radial direction and the tangential direction at all times, if the separation gap is large, fretting separation, that is, tapping and wear. It develops to the next stage of insulation deterioration, and thereafter, it becomes a dangerous state that the dielectric strength rapidly decreases.
[0018]
Re-impregnation at an appropriate time is indispensable in order to recover such a thin insulating layer and prevent the progress of secondary insulation deterioration. From these experimental results, the following can be said.
[0019]
1) The insulation layer peels off in layers as the insulation deterioration progresses.
[0020]
2) It is necessary to impregnate a very small gap of 20 to 50 μm with a liquid insulating material.
[0021]
From the two points, an experimental apparatus as shown in FIG. 1 was prepared in the sense of actually measuring the penetration resistance of the viscous varnish.
[0022]
The apparatus of FIG. 1 tests the relationship between the surface tension and the varnish penetration rate. This test apparatus aligns one end of two glass epoxy plates and holds the other side in a slightly open state. Is immersed in a varnish contained in a container, and this is tilted to 30 degrees from the vertical to observe the state of change in the osmotic force by which the varnish rises.
[0023]
In this device, capillary action, that is, the surface tension of the varnish, becomes the penetration force into the gap. As the varnish penetrates, the weight and surface tension of the penetrated varnish are balanced, so it is also a test device for quantifying the surface tension of the varnish.
[0024]
Here, in order to check the surface tension of the varnish, there are the following three purposes.
[0025]
1) Evaluation of the penetration rate into the gaps between the core slots in the penetration impregnation that has been performed for a long time.
[0026]
2) Evaluate the action of resisting varnish outflow that occurs in the heat curing process after re-impregnation by vacuum impregnation.
[0027]
3) Obtain a reference value for the evaluation of the upper limit of the rotational speed in the rotational drying assumed as one of the outflow suppression.
[0028]
The test apparatus shown in FIG. 1 uses a glass epoxy plate having a thickness of 2 mm, which is commercially available as a printed circuit board, so that the gap is tapered. In FIG. 1, the gap is 50 mm from the right end where the gap is zero, the gap is 100 μm, the gap is 100 μm, and the gap dimension is 200 μm... Yes.
[0029]
The reason why the glass epoxy plate was used is that the coil of the actual machine is made by impregnating the glass tape with the epoxy varnish. . Although the figure is upright, the test is actually performed at an angle of 30 degrees from the horizontal in order to support the apparatus.
2. Evaluation of surface tension
The experiment was conducted using a commercially available epoxy varnish for impregnation and preparing a low viscosity material of about 1 poise and a high viscosity material of about 15 poise. In addition, the test is carried out with 20 ° C. water whose surface tension is to be compared and whose characteristics are well known.
[0030]
FIG. 2 shows the test results. FIG. 2 is a comparison of the surface tensions of water and epoxy resin, with the final penetration length on the vertical axis and the gap length on the horizontal axis.
[0031]
This is the result observed when the surface tension and the weight of the penetrated varnish balance and the further penetration stops.
[0032]
The result of this test is theoretically a right-angled hyperbola on the figure, but the result of the experiment has a peak at 20 μm for both water and varnish. In the region where the gap is small, the resistance increases due to the surface roughness, so it is considered that there is a maximum value.
The peak value at 20μ is
Water; 110 mm, specific gravity 1
Varnish (1.0 poise); 200 mm, specific gravity 1.15
Varnish (15 poise); 190mm, specific gravity 1.15
It is. Considering the ratio of the penetration depth and the specific gravity, the surface tension of the varnish can be estimated to be twice that of water.
The surface tension calculated from this result is
Water 10.8 dyn / cm
Varnish 21.6 dyn / cm
Also, from the relationship of using the Hagen Poiseuille equation in the examination of permeability in the next item, when converted to pressure ΔP,
Water 55 mmAq (5400 dyn / cm²)
Varnish 110mmAq (10800dyn / cm²)
Thus, it can be seen that it is surprisingly large when compared with the numerical value of the discharge pressure of the cooling fan of the electric motor.
3. Evaluation and theoretical examination of varnish permeability
FIG. 3 shows the examination of the penetration rate of water at 20 μm. The vertical axis shows the penetration distance and the horizontal axis shows the penetration time.
[0033]
FIG. 4 shows a study of the penetration rate of a 0.1 poise epoxy resin with a gap of 20 microns.
[0034]
FIG. 5 shows a study of the penetration rate of 15 poise epoxy with a 20 μg gap.
[0035]
3 to 5 show the permeation process of water, 1.0 poise varnish, and 15 poise varnish. Although this figure mainly explains the place of 20μ, in FIGS. 4 and 5, the data of the place of 100μ is shown for reference.
[0036]
Moreover, in FIGS. 4-6, the time characteristic of water and varnish penetration is compared with a theoretical formula. In the figure, two theories are used, one is an equation that derives the gap as a circular tube, and the other is an equation that the gap opening is derived as a parallel gap that is sufficiently wide with respect to the gap length. is there.
[0037]
For the cylindrical model, it is obtained from the Hagen-Poiseuille average flow velocity equation shown below.
[0038]
V = (r^Three/ 8η) (ΔP / L)
V: Average flow velocity (cm / s)
r: radius of the tube (cm)
Note) Assign the gap length value here.
η: Viscosity (Poise)
ΔP: differential pressure (dyn / cm²)
L: Tube distance (varnish penetration distance, cm)
Since L changes with the penetration of the varnish, the theoretical calculation of the varnish penetration characteristics is based on sequential calculation. The equation for the average flow velocity in the case of a parallel gap is similar to the Poiseuille equation, but the value is about 10 times.
[0039]
V = (g²/ 8η) (ΔP / L) (32/3)
Where g: gap length (cm)
Other symbols are the same as Poiseuille's formula
From the figure, it can be seen that the Poiseuille's equation assumed to be a circular tube underestimates the penetration as 1/10. In the case of the model with the glass epoxy plate this time, it can be considered that the entrance of the varnish is sufficiently wide with respect to the gap length.
[0040]
In the case of varnish, it is considered that the experimental result and the theoretical calculation result of the parallel gap agree very well.
[0041]
However, in the case of an actual machine in which the varnish is infiltrated into the coil where the armature coil insulating layer is peeled off, the front entrance of the varnish is estimated to be about 1 cm. Think about what to do.
[0042]
In addition, the theoretical calculation of the parallel gap is inclined, but the experimental result is saturated because the theoretical calculation is a calculation in the state of horizontal installation. This is because a decrease in ΔP due to the weight of the varnish is not taken into consideration.
4). Testing and evaluation of varnish curing properties
(1) Temperature characteristics of varnish curing time (gel time)
In examining the method of suppressing varnish outflow due to a temporary viscosity drop during the drying process after impregnation, the relationship between the varnish curing temperature and the curing time was tested and confirmed as a basic characteristic.
[0043]
Here, the term “curing” is used for the point when the viscosity suddenly increases and suddenly changes from a liquid to a soft solid because it focuses on the suppression of outflow during heat curing. Or, it should be called primary curing, but technical terms are intentionally avoided because of the progress of this experiment from the viewpoint of equipment technology that extends the life of electrical equipment.
[0044]
FIG. 6 shows a history of the curing time and the varnish temperature during curing at three stages of temperatures of 140 ° C., 150 ° C., and 160 ° C. in an oven that performs temperature control.
[0045]
FIG. 6 relates to the examination of curing temperature, curing time, and reaction heat. The vertical axis represents the temperature of epoxy or silicon, and the horizontal axis represents the curing time. In the figure, the solid line indicates epoxy, and the dotted line indicates silicon.
[0046]
In this experiment, the varnish is placed in a test tube and placed in the center of the oven, and the varnish is cured. To confirm varnish hardening (gelation), a piano wire is placed in the varnish in the test tube in advance. Using a jig that can move the piano wire up and down from the outside with the oven door closed, check the state that the test tube is lifted together with the piano wire by solidifying the varnish from the oven front glass window, hardening, Gelation was determined.
[0047]
If the start of the curing time is 20 minutes after the start of operation when the varnish temperature reaches a predetermined temperature range, the curing time at each temperature is
140 ° C: 80 minutes
150 ° C .: 50 minutes
160 ° C .: 20 minutes
Therefore, it can be seen that it generally follows the 10 ° C. half law of thermal degradation.
[0048]
In FIG. 6, the temperature rise of the silicon oil performed under the same conditions is also shown with a dotted line. The difference (increase) between the temperature of the silicone oil and the temperature of the varnish can be regarded as the reaction heat of the varnish. Finding the cumulative sum of this temperature difference every 5 minutes (from oven start to curing)
140 ° C: 31.8K
150 ° C .: 29.8K
160 ° C: 34.3K
The values are almost the same.
[0049]
This is considered to suggest that the amount of heat (calorie) necessary for curing the varnish is constant regardless of the curing temperature as long as it exceeds the glass transition temperature.
(2) Temperature characteristics of varnish viscosity
Using a 100 cc heat-resistant beaker, the relationship between the temperature and viscosity of the varnish was measured by a hot water bath method. A B-type viscometer with a digital display was used for the viscosity measurement, and silicon oil was used for the water bath.
[0050]
FIG. 7 shows an example of the result. This figure shows the effect of varnish viscosity on temperature, with the vertical axis representing the epoxy viscosity and the horizontal axis representing the epoxy temperature.
[0051]
The figure shows three examples of viscosity at room temperature of 40 cP (0.4 poise), 530 cP (5.3 poise), and 5320 cP (53.2 poise).
[0052]
Here, the 40 cP example assumes a “new” product during varnish treatment, and the 530 cP does not perform a drying process immediately after vacuum re-impregnation, leaves it for a certain period of time, and waits for the viscosity to rise before drying. The sample was prepared by leaving it to stand at 40 ° C. for 7 days, and 5320 cP had a viscosity of about 10 times or 10 times when the viscosity was significantly increased by standing at 40 ° C. for 14 days. And it is almost a geometric series.
[0053]
As is clear from this figure, the new varnish has a viscosity of 1/10 with an increase of 100 ° C., and is therefore estimated to be about 30 ° C. halved. Since the curing time is halved by about 10 ° C., it is considered that varnish outflow during curing is less when the curing temperature is raised.
[0054]
For the example after standing at 40 ° C. × 7 days / 14 days, the test between 100 ° C. and 150 ° C. has not been completed, but by increasing the viscosity by leaving it, the decrease in viscosity during the varnish curing process is reduced. , Showing the possibility of connecting to varnish outflow control measures.
(3) Measurement of viscosity change during varnish curing
Using the same test apparatus as the temperature characteristics of the varnish viscosity, the varnish viscosity during curing was measured. An example is shown in FIG.
[0055]
FIG. 8 compares the results at 130 ° C., 140 ° C., and 150 ° C., and the curing time is halved by about 10 ° C., similar to the test results in the oven. Moreover, the following is clear from FIG.
[0056]
1) The viscosity rises immediately before curing (gelation)
2) The minimum value of the viscosity is once shown at the start of operation for 20 minutes. After that, continue to gradually increase until just before curing.
Although illustration is omitted, it corresponds temporally to a gradual rise in varnish temperature, which is considered to be due to reaction heat.
[0057]
In FIG. 8, the minimum viscosity during curing is seen to be 20 ° C. half (30 ° C. half in FIG. 7), but the curing time is almost 10 ° C. half, so the varnish outflow suppression verification was performed by setting the curing temperature higher. ing.
5. Far infrared application trial and its evaluation
Various methods can be considered for the irradiation of far infrared rays. Here, an example is shown in which the same open surface is treated with ceramics for radiating far infrared rays and with two types of untreated ones. Yes.
[0058]
B) With or without far-infrared rays, b) Convection wind speed in oven (larger convection and normal convection), and c) Comparison experiment between aluminum and normal heat-resistant glass as test tube material All the temperatures are 150 ° C.
(Comparison of varnish temperature rise during curing)
FIG. 9 shows an example of the far-infrared effect on epoxy curing, where the vertical axis indicates the temperature of epoxy or silicon, and the horizontal axis indicates the curing time. Line A has far infrared rays, the wind speed in the oven is large, and an aluminum tube is used as a test tube. In this figure, the solid line indicates epoxy and the dotted line indicates silicon.
[0059]
Furthermore, the line B is a) no far infrared ray, b) the oven wind speed is low, and c) the test tube uses a glass tube. The solid line indicates epoxy and the dotted line indicates silicon.
[0060]
FIG. 9 shows a comparison between the curing time and the varnish temperature rise during curing in the fastest and slowest cases (equivalent in the case of a normal laboratory) out of a total of 8 types of 2 types and 3 conditions. Is shown.
[0061]
As in the case of FIG. 6, the curing time (gelation time) is 30 in the fastest case and 80 minutes in the slowest normal case, if 20 minutes are subtracted from the start. From this figure, it can be seen that, despite the same set temperature of 150 ° C., the difference is more than twice due to the selection of conditions.
[0062]
In FIG. 9 as well, the change in the temperature of the silicone oil is also shown as in FIG.
Looking at the temperature difference between the varnish and silicon, when an aluminum tube is used, the temperature difference that is the distance between the two lines indicated by the solid line and the dotted line is small as indicated by the line A. However, when a glass tube is used, the temperature difference is large as shown by line B.
[0063]
From this, assuming that the amount of heat (calorie) required for the reaction is the same, this difference in temperature rise is considered to be the difference in thermal resistance between aluminum and glass of the test tube material, and heat transfer is the material of the container. However, aluminum is better.
[0064]
Considering that the amount of heat per unit time (Js = W) is replaced with a current source, a temperature rise is equivalent to a voltage drop, and a thermal resistance is replaced with an electrical resistance. At this time, it is considered that the temperature difference is increased on the same principle that the voltage drop increases as the resistance increases even at the same current value.
6). Effect map of resin curing acceleration
FIG. 10 shows the state of curing of the epoxy resin in consideration of far-infrared rays and other conditions. The vertical axis represents the four test conditions, and the horizontal axis represents the curing time.
[0065]
Select 6 types from the 8 types of conditions we conducted this time, b) Effect map for promoting hardening of aluminum or glass of test tube material, b) Large and small convection wind speed, and c) Convection wind speed. Indicated.
[0066]
The first stage is irradiation with far infrared rays, high convection wind speed in the oven, and the case where aluminum is used as the material of the test tube. In this case, the epoxy is cured in “29 minutes”.
[0067]
The second stage is the case where there is no far infrared irradiation, the convection wind speed in the oven is high, and aluminum is used as the material of the test tube. In this case, the epoxy is cured in “45 minutes”.
[0068]
The next third stage is the case where there is no far infrared irradiation, the convection velocity in the oven is low, and aluminum is used as the material of the test tube. In this case, the epoxy resin is cured in “60 minutes”.
[0069]
The last 4th stage is the condition that there is no far-infrared irradiation, the convection velocity in the oven is low, and the heat conduction using glass as the test tube material is the worst. In this case, the epoxy is cured in "80 minutes" are doing.
[0070]
The following can be said from this drawing.
[0071]
1) The time for curing the epoxy resin can be shortened by irradiating far infrared rays from the ceramic sprayed surface.
[0072]
2) The heat transfer effect can be improved by using a combination of infrared irradiation while heating with a large amount of convection of hot air.
[0073]
3) If the material of the container for containing the resin is a material having good thermal conductivity, and the conditions 1 and 2 are used in combination, the curing time of the resin can be shortened.
(Example)
Next, with reference to the drawings, a method for regenerating an aging electric device, particularly a rotating armature whose insulating layer has deteriorated due to aging will be described.
[0074]
FIG. 11 shows a method of regenerating the rotary armature 1 of a large DC generator as the rotary armature. The rotary armature 1 (rotor) is obtained by disassembling a DC generator.
[0075]
As a first step, the rotary armature 1 is kept in a high vacuum (eg, 0.26 to 0.5 kPa) for about 3 hours in a room or tank that can be evacuated to sufficiently perform deaeration.
[0076]
Then, the rotary armature 1 is dipped in a container containing varnish in the high vacuum room or tank, and is kept immersed in the varnish for about one day. In this state, the winding of the rotary armature 1 and the slot portion that accommodates it are impregnated with varnish.
[0077]
Next, the rotary armature 1 that has been impregnated with the varnish is attached to the shaft portion 1a, 1b at the end of the rotary armature 1 on the bearing portion 4 at the top of the support 3 provided in the drying chamber 2 of FIG. Is supported by fitting.
[0078]
A coupling 5 is provided on the shaft 1b, and a chain 9 is applied between a sprocket wheel 6 attached to the shaft at the end of the coupling 5 and a sprocket wheel 8 provided on the shaft of the motor 7. The motor 7 rotates the rotary armature 1 slowly.
[0079]
An iron core portion 1c is formed at the central portion of the rotary armature 1, and a coil is wound around this portion although details are not shown. The lead portions at both ends of the coil are connected to the commutator 1d.
[0080]
The problem is that the glass tape or mica glass tape provided between the periphery of the coil disposed in the slot of the iron core portion 1c and the other coils, or between these coils and the slot of the iron core portion. It is the age-related deterioration of the insulating layer made of
[0081]
When the large DC machine is disassembled and the rotary armature 1 (rotor) is taken out from the stator (stator) side, this deteriorated insulating layer is left as it is, and it is forcibly peeled off or given vibration to give a fine powder. Therefore, it is necessary to consider that the insulation distance cannot be maintained by maintaining the insulation distance between the coils or between the coils and the slots of the iron core.
[0082]
A heating device 10 is provided on the ceiling of the drying chamber 2. The heating device 10 includes a duct-shaped hot air generator 11 and a heating plate 12. The hot air generator 11 is provided with a fan 14 in the vicinity of the air inlet 13, and is heated by a heater 12 a while the air in the drying chamber 2 sucked from the inlet 13 passes through the duct portion of the hot air generator 11. It is heated and ejected from the discharge port 15 on the opposite side into the drying chamber 2 as heated air a.
[0083]
As shown in FIG. 13, the heating plate 12 is of an electrothermal type, and a sheathed heater H is meandered between the lower plate P1 and the upper plate P2 made of a porous plate. The air heated to a high temperature by the heater H through the small hole h is discharged into the hot air generating part 11, that is, the duct part, and the passing air is heated.
[0084]
A heat radiating plate 12b is provided below the lower plate P1, and a ceramic layer 12c having a plurality of layers is formed on the surface of the heat radiating plate 12b. This ceramic layer 12c is formed by plasma spraying ceramic powder so as to emit far-infrared rays R having a predetermined wavelength.
[0085]
The ceramic layer 12c formed by the plasma spraying process heats the heat radiating plate 12b with a heater 12a, and the thermal energy obtained by this heating has an optimum wavelength for heating the rotary armature 1 that is a heated object. It has a characteristic of emitting far-infrared rays R.
[0086]
For example, an aluminum plate or a stainless steel plate is used as the heat radiating plate 12b, and titanium oxide (TiO2) and aluminum oxide (Al2O3) are used as the material of the ceramic layer 12c formed on the surface thereof.
[0087]
In FIG. 14, the ceramic layer 12c is formed in a plurality of layers, and the titanium oxide layer T and the aluminum oxide layer A are formed in a two-layer structure on the surface of the metal plate B (base plate) constituting the heat radiating plate 12b.
[0088]
As the heat radiating plate 12b having the ceramic layer 12c composed of a plurality of layers, one having the following conditions is adopted.
“A thermal converter made of a conductive material of thermal energy is placed between a heat source that gives thermal energy and a heat receiving side that receives the thermal energy, and the thermal converter is heated. A heat transfer method for dissipating heat as radiant heat energy from the heat dissipation surface,
A thin ceramic layer having a plurality of layers is formed on the surface of the heat conversion body, and this ceramic layer has a property of emitting infrared rays by heating, and a short wavelength having a center frequency of infrared rays of 4 to 6 mμ in a moving direction of thermal energy. , Having a wavelength selected from a medium wavelength of 7-9 mμ and a long wavelength of 10-20 mμ,
The ceramic layers are laminated in the order of short wavelength / medium wavelength, short wavelength / long wavelength, medium wavelength / long wavelength, or short wavelength / medium wavelength / long wavelength ”
This invention is applied.
[0089]
The present invention has been filed on November 16, 2001 as Japanese Patent Application No. 2001-352007 as “Heat Transfer Method and Apparatus”, and can be used very effectively for a method of transferring heat energy. . Specifically, the present invention can be applied to a main body of an engine for a vehicle, a radiator of the engine, a water pipe of a boiler, a wing of a blower, and the like.
[0090]
Now, referring again to FIG. 11, a cylindrical local heating device 20 is provided so as to surround the periphery of the commutator 1 d of the rotary armature 1. In the process of curing the epoxy resin impregnated in the coil portion or the like by the action of this local heating device 20, the viscosity suddenly decreases and the epoxy resin impregnated in the coil portion wound around the iron core portion 1c becomes It is intended to prevent leakage.
[0091]
As shown in FIGS. 12 and 14, the local heating device 20 promotes the curing of the epoxy resin that is an insulating material, and is formed in a cylindrical shape so as to surround the commutator 1 d where the epoxy resin easily flows out. A heater 20a (electric heater) is used.
[0092]
A ceramic layer 20b is formed on the inner surface, and the heat generated by the heater 20a is converted into an infrared ray having a wavelength at which the epoxy resin is easily cured by converting the frequency by energy conversion, and in particular the portion of the commutator 1d. Heated higher than other parts. It is obvious that the local heating device 20 is not limited to the above-described structure, and may have another structure as long as it has a structure that accelerates the curing rate by local heating.
[0093]
In this way, the “bank term effect” that hardens the portion where the epoxy resin, which is an insulating material, is difficult to flow out, to thereby cure the epoxy resin that wraps the coil held in the iron core portion 1c, that is, the insulating layer. It can be cured while being held at a predetermined thickness.
[0094]
In the embodiment of the present invention, the description is centered on the regeneration of the rotary armature of a large DC machine. However, even other electrical equipment uses an insulating resin that cures by applying heat. Then, in the case where the viscosity is abruptly lowered during curing, it can be carried out in the same manner as described above.
[0095]
【The invention's effect】
After holding the rotary armature under vacuum as described above, after impregnating the coil portion with a liquid of an insulating resin, the hot armature at a predetermined temperature is slowly rotated while rotating the rotary armature slowly. The far-infrared rays are irradiated and heated, and the commutator portion is particularly heated, so that the curing of the resin can be accelerated locally.
[0096]
Therefore, due to the viscosity change that temporarily decreases during the curing of the resin, the outflow of the epoxy resin that is to flow out can be prevented by the resin portion that has been cured first.
[0097]
As a result, it becomes possible to easily regenerate and reuse the insulation part of a large-sized DC machine that has been in operation for 30 years or more and has aged and has reached the end of its life, and a great economic effect can be exhibited.
[Brief description of the drawings]
FIG. 1 is a schematic view of a test apparatus for surface tension and penetration rate of varnish.
FIG. 2 is a diagram comparing surface tensions of water and epoxy resin.
FIG. 3 is a diagram showing the results of examining the water penetration rate at 20 μm.
FIG. 4 is a graph showing the results of examining the penetration rate of 20 μg 15 poise epoxy.
FIG. 5 is a graph showing the results of examining the penetration rate of 20 μg 15 poise epoxy.
FIG. 6 is a diagram showing the examination results of resin curing temperature, curing time, and reaction heat.
FIG. 7 is a graph showing changes in varnish viscosity with temperature.
FIG. 8 is a diagram showing a change in viscosity during curing of an epoxy resin.
FIG. 9 is a diagram showing the contribution of infrared rays to the curing of the epoxy resin.
FIG. 10 is a diagram showing a curing rate of an epoxy resin under far infrared and other conditions.
FIG. 11 is an explanatory diagram of a process for recovering the insulation of the rotary armature.
FIG. 12 is a front view of a local heating device.
FIG. 13 is a cross-sectional view of a heating plate portion of the heating device.
FIG. 14 is a cross-sectional view of a heating plate portion.
[Explanation of symbols]
1 Rotating armature 1a, 1b Shaft 1c Iron core
1d Commutator 2 Drying room 3 Support stand
4 Bearing part 5 Coupling 6, 8 Sprocket wheel
7 Motor 9 Chain 10 Heating device
11 Hot air generating part 12 Heating plate part 12a Heating heater
12b Heat sink 12c Ceramics layer 13 Suction port
14 Juan 15 Exhaust vent

Claims (3)

A process in which a rotating armature whose insulating layer has deteriorated due to aging is immersed in a liquid insulating material under vacuum to impregnate the insulating layer with the insulating material, and drying in which heated air is circulated through the rotating armature . A method for regenerating an aging electrical equipment comprising a step of solidifying an insulating material impregnated in the insulating material while rotating in a room to form a new insulating layer, and surrounding a commutator of the rotating armature The portion of the commutator of the rotating armature is locally heated by infrared rays emitted from the ceramic layer on the inner surface of the electric heater of the local heater provided to surround the insulating material of the commutator portion of the rotating armature. A method for regenerating an obsolete electrical device characterized in that solidification is accelerated earlier than other parts . The heating device provided on the ceiling of the drying chamber heats the air in the drying chamber sucked from the air suction port of the hot air generating unit provided on the back side of the heater by the heater and discharges the air from the discharge port on the opposite side. Liquid insulation in which the rotary armature is impregnated by emitting far-infrared rays into the drying chamber from a ceramic layer laminated on a radiator plate provided on the drying chamber side of the heater while being ejected as heating air into the drying chamber 2. The method for regenerating an aging electrical apparatus according to claim 1, wherein the material is solidified to form a new insulating layer. The ceramic layer is formed by plasma spraying ceramic powder on the surface of a heat sink, and the ceramic layer is made of titanium oxide as the first layer on the surface side of the heat sink, and the second layer thereon is formed. 3. The method for regenerating an aged electrical device according to claim 2, wherein the method is formed in a plurality of layers made of aluminum oxide.

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