CN111091967A - Coil curing method of magnetic focusing Hall thruster - Google Patents
Coil curing method of magnetic focusing Hall thruster Download PDFInfo
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- CN111091967A CN111091967A CN201811242935.5A CN201811242935A CN111091967A CN 111091967 A CN111091967 A CN 111091967A CN 201811242935 A CN201811242935 A CN 201811242935A CN 111091967 A CN111091967 A CN 111091967A
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F41/00—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties
- H01F41/02—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets
- H01F41/04—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets for manufacturing coils
- H01F41/12—Insulating of windings
- H01F41/127—Encapsulating or impregnating
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Abstract
A coil curing method of a magnetic focusing Hall thruster belongs to the technical field of Hall electric thrusters. In order to solve the problem that the temperature of the central area of an excitation coil is too high when a Hall thruster works in a high vacuum environment, the invention provides a coil curing method of a magnetic focusing Hall thruster. The method is beneficial to the long-term stable on-track operation of the magnetic focusing Hall thruster.
Description
Technical Field
The invention relates to the technical field of Hall electric thrusters, in particular to a coil curing method of a magnetic focusing Hall thruster.
Background
The Hall thruster is widely applied to space propulsion tasks such as satellite position keeping and orbit conversion due to the simple structure, the proper specific impulse and the high efficiency. The magnetic focusing Hall thruster generates a magnetic field through the excitation coil, and the excitation coil has certain resistance, so that heat can be generated when current passes through the excitation coil. When the Hall thruster works in a high vacuum environment, the contact area between each layer of conducting wires of the magnet exciting coil is small, and even gaps (the gaps can only transfer heat by radiation) are locally formed, so that the contact thermal resistance between each layer of conducting wires is very large, the heat conducting performance of an insulating material wrapping the conducting wires is poor, the heat transfer effect between each layer of conducting wires is extremely poor, and the most direct result is that the temperature of the central area of the magnet exciting coil is overhigh.
The magnet exciting coil works at high temperature for a long time to accelerate the aging failure of the insulating layer, each layer of conducting wire loses the protection of the insulating layer and is possibly short-circuited, or the conducting wire is in contact with the shell of the thruster to enable the shell to be electrified, so that the distribution of a magnetic field and an electric field of the thruster is influenced, and the thruster cannot work normally.
Disclosure of Invention
In order to solve the problems of insulating layer failure and excitation coil short circuit caused by the insulating layer failure due to the fact that the temperature of the central area of the excitation coil is too high when the Hall thruster works in a high vacuum environment, a coil curing method of the magnetic focusing Hall thruster is provided, in the process of winding the coil, heat-conducting fillers are sprayed on the surface of the coil and then heated and cured, and the heat-conducting fillers are made of high-temperature-resistant paint and heat-conducting substances.
Further defined, the high temperature resistant coating is composed of a binder and a solid insulator, the binder is composed of a component A and a component B which are independently packaged, wherein the component A is an adhesive; the component B is a curing agent; when in use, the component A and the component B are mixed according to the mass ratio of (1.2: 1) to (1.6: 1) and then cured.
Further defined, the heat conductive filler is prepared by the following method:
1) the binder component a was mixed with component B as follows (1.2: 1) to (1.6: 1) mixing the components in percentage by mass, curing, and mixing the components in percentage by mass according to the following ratio: mixing the solid insulator and the cured binder according to the mass ratio of (1.6: 1) - (1.8: 1) to prepare a cured coating;
2) curing the coating: and (3) mixing the heat-conducting substance with the cured coating to prepare the heat-conducting filler, wherein the mass ratio of the heat-conducting substance is (1:0.02) to (1: 0.03).
Preferably, in step 1), component a and component B of the binder are mixed according to the formula (1.3: 1) to (1.5: 1) mixing the components in the mass ratio, and curing.
More preferably, the component A and the component B in the binder in the step 1) are mixed according to the mass ratio of 1.4:1 and then cured; the binder and the solid insulation were mixed in a mass ratio of 1.7: 1.
Further, the curing in the step 1) is to mix the component A and the component B in the binder and stir for 4-5 hours.
Further defined, the cured coating and the heat-conducting substance in the step 2) are mixed according to the mass ratio of 1: 0.02.
Further, the heat conducting substance is nano-oxide or hexagonal boron nitride, wherein the nano-oxide is nano-alumina, nano-magnesia or nano-lanthanum oxide.
Further defined, the heat-conducting substance is in a powder shape, and the particle size is less than 0.5 μm.
Further, the heating and curing means that the coil sprayed with the heat-conducting filler is heated to 40 +/-5 ℃, the temperature is kept for 30min, then the coil is heated to 90 +/-5 ℃, the temperature is kept for 1h, the coil is continuously heated to 280 +/-5 ℃, the temperature is kept for 1h, and the coil is continuously heated to 450 +/-5 ℃ and the temperature is kept for 6 h.
Advantageous effects
The invention changes the proportion of the binder and the solid insulator in the original high-temperature resistant coating, reduces the content of the binder in the high-temperature resistant coating, and adds the nano oxide powder or the hexagonal boron nitride powder with better heat conductivity after curing the high-temperature resistant coating. In the process of winding the magnet exciting coil, the high-temperature-resistant coating added with the nano oxide powder or the hexagonal boron nitride powder is uniformly sprayed on the surfaces of all layers of wires to serve as fillers between all layers of wires and between the wires and magnetic poles, and finally the magnet exciting coil is heated to realize the solidification of the coil, so that the following beneficial technical effects are obtained:
1. in the curing method, the proportion of the binder and the solid in the original high-temperature resistant coating is changed, the content of the binder in the high-temperature resistant coating is reduced, the coating is better attached to the surface of the excitation coil, and the coil curing is convenient to realize.
2. After the high-temperature-resistant coating is cured, the nano oxide powder or the hexagonal boron nitride powder with better heat conductivity is added, so that the heat conductivity of the coating is improved, the heat transfer effect of the excitation coil is improved, the surface temperature of the central area of the excitation coil is reduced, and the coating has important significance for the long-term stable on-track operation of the magnetic focusing Hall thruster.
3. The invention effectively improves the working environment of the excitation coil, and the excitation coil cured by the method has obviously improved heat conduction capability under the action of the heat conduction filler, and can effectively reduce the temperature of the surface of the excitation coil, so that the insulation layer of the coil cannot fail due to overheating. The test result of the insulation resistance of the coil surface is 35M omega-713M omega, the mean value is 248.75M omega, the confidence interval of the measured value of the insulation resistance under the condition of the confidence coefficient of 0.99 is (168.66M omega, 328.84M omega), and the insulation resistance requirement of the coil is 20M omega; and performing high-low temperature cycle test experiments at room temperature to 450 ℃, wherein the insulation resistance test value after ten cycles is 78M omega-823M omega, and is still higher than the requirement of 20M omega for the insulation resistance of the coil. The test result shows that the insulating property and the temperature resistance of the excitation coil are greatly improved under the action of the heat-conducting filler, so that the excitation coil can work for a long time without generating faults such as short circuit and the like.
Drawings
Fig. 1 is a schematic diagram of a curing process of an excitation coil.
Fig. 2 is a schematic structural diagram of an excitation coil, in which 1 is a conducting wire, 2 is an insulating layer, 3 is a heat-conducting filler, and 4 is a magnetic pole.
Detailed Description
The adhesive, the curing agent and the solid insulator have no special requirements on specific substances, and are all the adhesive, the curing agent and the solid insulator which are commonly used in the field and can have a high-temperature resistant function.
Binder component A Binder used in the following examples was purchased from quark nanomaterials, Inc. of Shenzhen, lot number KS180615001, product type number: EC-53468A.
The component B curing agent of the binder is purchased from quark nano materials Limited company of Shenzhen, batch number KS180615001, and the product model is as follows: EC-53468B.
The solid insulator is purchased from quark nanometer materials Limited company of Shenzhen, batch number KS180615001, and the product model is as follows: EC-53468C.
The coil surface insulation resistance test adopts a VictorVC60B + model digital insulation resistance tester produced by Shenzhen Shenli Gaoelectronics technology Limited.
The invention adds nano or other kinds of heat-conducting filling materials into the high-temperature resistant coating, mixes the materials according to a certain proportion, and sprays the materials as heat-conducting fillers on the surface of each layer of conducting wire in the winding process of the excitation coil, and then the excitation coil coated with the fillers is placed in a high-temperature environment for curing. The contact area between the wires of each layer of the solidified excitation coil is increased under the action of the filler, and the contact thermal resistance is reduced; the heat conduction and heat dissipation capacity of the coil is enhanced under the action of the nanometer heat conduction filler, and heat generated by the excitation coil is conducted to the bottom plate of the Hall thruster through the filler, so that the surface temperature of each layer of conducting wire can be effectively reduced.
The invention is further described below with reference to the accompanying drawings.
Example 1. coil curing method of magnetic focusing hall thruster.
The coil curing method according to the present invention is explained with reference to fig. 1.
The embodiment relates to preparation of high-temperature-resistant paint, preparation of a heat-conducting filler, spraying of an excitation coil and heating and curing.
1) Mixing a binder component A, a high-temperature resistant adhesive, a product number: EC-53468A, adhesive component B, high-temperature resistant curing agent, product number: EC-53468B, stirring for 20-30 minutes respectively until uniform, mixing the components A: the component B was added to the component a at a ratio of 1.4:1 (mass ratio) to obtain a binder, and the binder was stirred for 4 hours to cure.
According to the adhesive: solid insulating material (i.e., solid substance) 1.7:1 (mass ratio) solid insulating material, product number: and EC-53468C, stirring for 20 minutes, adding into the cured binder, sealing and standing for 1 hour, filtering with a 300-mesh 400-mesh cloth net, collecting the filtrate, and completing the preparation of the high-temperature resistant coating to obtain the cured coating.
2) Coating after curing: the ratio of the heat-conducting material to the heat-conducting material is 1:0.02, nano powder with the particle size of less than 0.5 mu m, which is nano alumina powder used in the embodiment, is added into the cured coating and is uniformly stirred, and the preparation of the heat-conducting filler is completed.
Winding an excitation coil, uniformly brushing the prepared heat-conducting filler between layers, standing the coil for 30 minutes after winding, heating to 40 +/-5 ℃ in a heating box, preserving heat for 30 minutes, then heating to 90 +/-5 ℃ in the heating box, preserving heat for 1 hour, continuously heating to 280 +/-5 ℃ in the heating box, preserving heat for 1 hour, continuously heating to 450 +/-5 ℃ in the heating box, preserving heat for 6 hours, cooling in an oven, finishing the heating and curing process of the coil, and obtaining the cured coil as shown in figure 2.
Example 2. coil curing method of magnetic focusing hall thruster.
Example 1 was repeated, except that nano-magnesia was used instead of nano-alumina and the other component distribution ratios and the curing process were the same as in example 1 in this example 1.
Example 3. coil curing method of magnetic focusing hall thruster.
Example 1 was repeated, except that nano lanthanum oxide was used instead of nano aluminum oxide and the other component distribution ratios and the curing process were the same as in example 1 in this example 1.
Example 4. coil curing method of magnetic focusing hall thruster.
Example 1 was repeated, differing from example 1 in that hexagonal boron nitride powder was used instead of nano alumina, and the other component distribution ratios and the curing process were the same as in example 1.
Example 5. coil curing method of magnetic focusing hall thruster.
Example 1 was repeated, which differs from example 1 in that the mass ratio of components a and B in the binder in step 1) in this example was 1.2: 1, the binder and the solid insulating substance are mixed according to a ratio of 1.6: 1, in a mass ratio of 1. Curing the coating and the heat-conducting substance in the step 2) according to the ratio of 1: 0.03 mass ratio.
Example 6. coil curing method of magnetic focusing hall thruster.
Example 1 was repeated, which is different from example 1 in that the mass ratio of a to B in the binder in step 1) in this example was 1.6: 1; the ratio of the binder to the solid matter is 1.8: 1, in a mass ratio of 1. Curing the coating and the heat-conducting substance in the step 2) according to the ratio of 1: 0.03 mass ratio.
And (3) inspecting the coil performance of the magnetic focusing Hall thruster cured by the method.
An insulation resistance tester is utilized to randomly select a plurality of test points on an excitation coil to measure surface insulation resistance, the test result of the coil surface insulation resistance is 35M omega-713M omega, the average value is 248.75M omega, the confidence interval of the insulation resistance measurement value under the condition of confidence coefficient 0.99 is (168.66M omega, 328.84M omega), and the requirements of the coil insulation resistance on 20M omega are met; and performing high-low temperature cycle test experiments at room temperature to 450 ℃, wherein the insulation resistance test value after ten cycles is 78M omega-823M omega, and is still higher than the requirement of 20M omega for the insulation resistance of the coil. The test result shows that the insulating property and the temperature resistance of the excitation coil are greatly improved under the action of the heat-conducting filler, so that the excitation coil can work for a long time without generating faults such as short circuit and the like.
Claims (10)
1. A coil curing method of a magnetic focusing Hall thruster is characterized in that in the coil winding process, heat conducting fillers are sprayed on the surface of a coil and then heated and cured, and the heat conducting fillers are made of high-temperature resistant paint and heat conducting substances.
2. The coil curing method of the magnetic focusing hall thruster of claim 1, wherein the high temperature resistant coating consists of a binder and a solid insulator, the binder consists of a component a and a component B which are independently packaged, wherein the component a is an adhesive; the component B is a curing agent; when in use, the component A and the component B are mixed according to the mass ratio of (1.2: 1) to (1.6: 1) and then cured.
3. The coil curing method of the magnetic focusing Hall thruster of claim 2, wherein the heat conducting filler is prepared by the following method:
1) the binder component a was mixed with component B as follows (1.2: 1) to (1.6: 1) mixing the components in percentage by mass, curing, and mixing the components in percentage by mass according to the following ratio: mixing the solid insulator and the cured binder according to the mass ratio of (1.6: 1) - (1.8: 1) to prepare a cured coating;
2) curing the coating: and (3) mixing the heat-conducting substance with the cured coating to prepare the heat-conducting filler, wherein the mass ratio of the heat-conducting substance is (1:0.02) to (1: 0.03).
4. The coil curing method for a magnetic focusing hall thruster of claim 3, wherein the ratio of the component A and the component B in the adhesive in the step 1) is (1.3: 1) to (1.5: 1) mixing the components in the mass ratio, and curing.
5. The coil curing method for the magnetic focusing Hall thruster according to claim 4, wherein in the step 1), the component A and the component B in the adhesive are cured after being mixed according to a mass ratio of 1.4: 1; the binder and the solid insulation were mixed in a mass ratio of 1.7: 1.
6. The method for curing the coil of the magnetic focusing hall thruster of claim 3, wherein the curing in the step 1) is to mix the component A and the component B in the adhesive and stir for 4-5 hours.
7. The method for curing the coil of the magnetic focusing hall thruster of claim 3, wherein the cured coating and the heat conducting substance are mixed in the step 2) according to a mass ratio of 1: 0.02.
8. The coil solidification method for the magnetic focusing Hall thruster according to claim 1, wherein the heat conducting substance is nano-oxide or hexagonal boron nitride, wherein the nano-oxide is nano-alumina, nano-magnesia or nano-lanthanum oxide.
9. The method for solidifying the coil of the magnetic focusing hall thruster of claim 8, wherein the heat conducting substance is in a powder shape and has a particle size of less than 0.5 μm.
10. The coil curing method of the magnetic focusing Hall thruster according to claim 1, wherein the heating curing is to heat the coil sprayed with the heat conductive filler to 40 +/-5 ℃ for 30min, then to 90 +/-5 ℃ for 1h, to continue to heat to 280 +/-5 ℃ for 1h, to continue to heat to 450 +/-5 ℃ for 6 h.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111768969A (en) * | 2020-06-18 | 2020-10-13 | 北京控制工程研究所 | Hall thruster excitation coil winding method |
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