25.Chemical Resistance Testing of Enameled Wire: Ensuring Durability and Reliability in Harsh Environments

Chemical Resistance Test: It examines the enamel's resistance to chemicals such as solvents, oils, and acids, which can degrade insulation over time.

The Chemical Resistance Test of enameled wire evaluates the insulation's ability to withstand exposure to various chemicals commonly encountered in industrial environments.

Here's how it typically works:

Selection of Chemicals: The test involves selecting a range of chemicals relevant to the wire's intended application or environment. This may include solvents, oils, acids, bases, and other substances known to potentially degrade insulation materials.

Preparation of Samples: Samples of the enameled wire are prepared according to specified dimensions and surface conditions to simulate real-world use.

Immersion or Exposure: The prepared wire samples are immersed or exposed to the selected chemicals under controlled conditions. The exposure may be conducted at ambient temperature or elevated temperatures, depending on the application requirements.

Duration of Exposure: The duration of exposure varies depending on the test protocol and the expected duration of contact with chemicals in the intended application. Typically, the samples are exposed for a predetermined period to simulate long-term exposure.

Observation and Evaluation: After the exposure period, the wire samples are visually inspected for signs of damage, such as discoloration, swelling, cracking, or degradation of the insulation material. Changes in electrical properties, such as insulation resistance, may also be measured.

Analysis of Results: The results are analyzed to determine the extent of damage or degradation caused by the chemical exposure. This information helps assess the suitability of the enameled wire for use in environments where exposure to specific chemicals is expected.

Comparison with Standards: The test results are compared against industry standards or specifications to ensure compliance with regulatory requirements and performance expectations.

By subjecting enameled wire to the Chemical Resistance Test, manufacturers can identify potential weaknesses in the insulation material and make informed decisions regarding material selection and product design to enhance durability and reliability in chemically challenging environments.

What materials are used in the enamel coating of winding wire?

Requirements of Chemical Resistance of enameled wire

Except for self-adhesive enameled wire, generally enameled wire must go through an impregnation process after being wound into a coil. The solvent in the impregnation paint has varying degrees of swelling effect on the paint film, especially at higher temperatures. During the use of the impregnated windings, the paint film may undergo thermal cracking due to the action of heat. Therefore, the compatibility of the impregnated paint and the enameled wire film has a great impact on the service life of motors, electrical appliances, and instruments. During use, the windings may come into contact with various surrounding media, such as contact with refrigerants in refrigeration devices and contact with various chemical gases in chemical plants. These media have varying degrees of corrosive effects on the paint film. Salt spray can also cause chemical corrosion to the winding coils of electrical products on marine vessels. In a transformer, the coils are in direct contact with the transformer oil. For direct welding enameled wires, electrical products require the enameled wire to have good pyrolysis properties of the paint film during the welding process, which requires the insulating layer of the enameled wire to have good chemical resistance.

The test items specified in the National Standard Chemical Properties of Enameled Wire Test Methods (GBT4074.4-2008) include solvent resistance, refrigerant resistance, direct weldability, hydrolysis resistance and transformer oil resistance.

In addition to the chemical resistance items stipulated in national standards, there are usually acid resistance, alkali resistance, salt water resistance, breakdown voltage retention rate after freeze aging, fluorine-free ethanol solubility, fluorine-free low-temperature compatibility, high temperature and high humidity aging, and impregnation. Evaluation of chemical properties such as paint compatibility.

Enameled Winding Wire: Suitability for High-Temperature Environments