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1. Types of motor insulating paper
The motor insulation paper commonly used in motors is divided into six grades of A, E, B, F, H and C according to its heat resistance.
1. Class A insulation includes organic fiber materials such as cotton yarn, silk, paper and other impregnated and magnetic paint on ordinary enameled wires. Currently only used in transformers. The allowable operating temperature of Class A insulation is 105°C.
2. Class E insulation includes films made of polyester resin, epoxy resin, triacetate, etc., polyvinyl acetal high-strength enamel wire magnetic paint, etc. Used in medium and small AC and DC motors. The allowable operating temperature of Class E insulation is 120°C.
3. Class B insulation includes mica, asbestos, glass wire and other inorganic substances with organic paint or resin (heat resistance treatment) as adhesive materials and their compositions, polyester high-strength enameled wire magnetic paint, etc. It is generally used in large and medium-sized synchronous machines and medium-sized and small AC and DC motors. The allowable operating temperature of Class B insulation material is 130°C.
4. Class F insulation includes synthetic resin paint modified with silicone organic compounds for inorganic substances such as mica, asbestos, glass wire, or materials or their compositions whose heat resistance meets the requirements of this grade of alkyd and epoxy resin as adhesives. The allowable operating temperature of Class F insulation is 155°C.
5. Class H insulation includes silicone organic matter and mica, asbestos, glass wire and other inorganic substances made of silicone organic paint as adhesive. It is mainly used in occasions where it is required to minimize size and reduce weight, such as aviation motors, crane motors, traction motors, etc. The allowable working temperature of H-grade composite insulation paper is 180°C.
2. Motor insulation paper thickness and kilowatt ratio
First of all, it needs to be clear that the paint film on the general copper wire has met the insulation conditions, but due to the conditions of production, transportation, wire embedding, drying and heating, etc., it is inevitable that the paint film will fall, which requires further insulation of the insulating paper. Secondly, the selection of insulation paper thickness does not have a fixed value, the general principle is that without increasing the difficulty of embedding, the thicker the better. Finally, this article collects some information from netizens about the thickness of motor insulation paper and the ratio of kilowatts, for reference only.
Netizen 1: Look at the power of the motor to determine, generally 10 dry watts below the motor insulation paper thickness of 0.17 mm, 10K watts above 0.21 insulation paper is appropriate.
Netizen 2: The center height of the motor is 80-112mm, the thickness of the motor insulation paper is about 0.25mm; the center height is 132-160mm, the thickness of the motor insulation paper is about 0.3mm; the center height is 180-280mm, and the thickness of the motor insulation paper is about 0.35mm.
Netizen 3: One layer of 0.25 mm insulating paper is used for more than 15 dry tiles and less than 90 dry tiles, and two layers for more than 100 dry tiles.
Netizen four: 45 kW motor insulation paper generally adopts 0.15-0.18mm thickness,
General principle: the thickness of the insulation paper should be selected as thick as possible to ensure the insulation performance of the motor and prevent the occurrence of motor heating, burning and short circuit. The selection of insulation paper requires consideration of the installation environment of the motor, such as the wet environment to choose moisture-resistant insulation paper; The heat-resistant temperature of the insulation paper must also meet the requirements of the motor.
3. Installation and cleaning method of motor insulating paper
The installation method of motor insulation paper is generally slot insulation (insulation between coil and slot), layer insulation (insulation with two windings under the same tank), end insulation (insulation between phases of the end coil), etc.
Motor insulation paper cleaning method: because the insulation paper has a certain hardness, therefore, the motor insulation paper that has been impregnated can be taken out by tapping and extruding, if the paste is too firm, you can also properly heat the motor, and take out the paint after softening.
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