The Characteristics of Micro-Arc Oxidation Ceramic Magnetic Wire for High Temperature Motor
The maximum tolerance temperature of the motor limits the winding current,thereby constraining the power density of the motor.The thermal resistance of a motor is influenced by the withstand temperature of the electrical insulation system(EIS).Insulating materials used in organic insulated magnetic wires for motors have limited thermal resistance levels and tend to decompose at high temperatures.Traditional ceramic and anodized magnetic wires exhibit poor flexibility,and their electrical properties deteriorate rapidly when bent or deformed.This paper proposes a motor winding scheme using micro-arc oxidation(MAO)ceramic magnetic wire.This wire is characterized by high-temperature resistance and excellent flexibility,maintaining electrical properties after deformation.The formation mechanism of MAO ceramic magnetic wire is described,and its main characteristics are explained.MAO ceramic magnetic wire has discharge channels,micropores,and cracks in its film layer to release deformation stress.The base metal and the film layer constitute a typical laminated composite structure,providing the magnetic wire with good mechanical toughness while maintaining the properties of the raw material.The high-temperature physical and insulation properties of the samples are tested.The samples can maintain reliable performance after baking at high temperatures and bending,indicating good temperature resistance and stable insulation performance.The wire is applied to a flux-switching motor to validate its feasibility in a high-temperature(HT)motor.The surface of the magnetic wire is first treated to increase its wear resistance and flexibility.The prototype stator undergoes baking in a high-temperature oven,with resistance and inductance changes measured at different temperatures and within seven days of baking at 350℃.Insulation resistances of interphases and phase-motor casing are measured at room temperature and 400℃.After baking,the resistance and inductance of the motor stator winding remain stable,and the insulation of the prototype exhibits a positive temperature coefficient characteristic.At high temperatures,insulation resistances of interphases and phase-motor casing are higher than those at room temperature.The results indicate that the motor winding based on MAO ceramic magnetic wire can operate stably in a high-temperature environment for an extended period.The high-temperature resistance of the assembled prototype is tested.After two hours of baking the motor in a 400℃muffle furnace,the motor is cooled to room temperature for an operational test.The motor runs normally after baking,confirming the suitability of the MAO ceramic wire prototype in high-temperature environments.The results demonstrate that MAO ceramic magnetic wire exhibits stable insulation under twisting and high-temperature conditions.It also has good mechanical toughness while maintaining the properties of the raw materials.After surface treatment,the MAO ceramic magnetic wire can be wound into motor windings and applied in motors.Using the high-temperature resistance of MAO ceramic magnetic wires,motors can surpass the limitations of traditional motor temperatures.
Micro-arc oxidationceramic magnetic wireinsulationhigh-temperature motor
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