The "types" and "characteristics" of enameled wire are as follows:

　　I. Classification by Insulating Varnish (Functional Properties)—This is the most critical dimension for determining “characteristics.”

　　1) Polyurethane enameled wire (International common abbreviation: UEW / Domestic national standard code: QA)

　　Direct solderability: Can be directly soldered with tin, eliminating the need for paint removal.

　　High frequency with low dielectric loss, easy to color, and convenient for harness identification.

　　With a temperature resistance of 130 ℃ to 155 ℃, this type of enameled wire is characterized by its ability to be directly soldered and its easy removal of the enamel coating.

　　Commonly used in applications such as small electronic components. Often found in precision coils, high-frequency relays, headphones, and small motors.

　 　2) Polyester enameled wire (international common abbreviation: PEW / domestic national standard code: QZ)

　　High mechanical strength, excellent solvent resistance, and moderate price.

　　With a temperature resistance of 130°C (Class B), this is the most widely used “economical” wire for ordinary motors, fans, and transformers.

　　3) Polyester-imide enameled wire (International common abbreviation: EIW / Domestic national standard code: QZY)

　　QZY—this code is determined in accordance with the relevant standards specified in the national standard GB/T 6109. The letter “Q” stands for enameled wire, “Z” corresponds to polyester, and “Y” corresponds to imide. Due to their excellent resistance to thermal shock and mechanical strength, this type of enameled wire is often used in windings of motors, electric tools, and other equipment with high heat-resistance requirements.

　　Heat-resistant up to 180 ℃ (Class H), with superior thermal shock and dielectric strength compared to QZ.

　　4) Polyimide enameled wire (International common abbreviation: PI/PIW; Domestic national standard code: QY)

　　QY, as defined by the relevant national standard GB/T 6109, typically features markings such as QY-1 and QY-2, where the numbers indicate the thickness grade of the漆膜. This type of enameled wire is suitable for harsh operating conditions involving high temperatures and is commonly used in special motors and windings of electronic components that demand exceptionally high insulation and heat resistance.

　　It can still operate reliably for extended periods at temperatures above 220 ℃ (Class C). Currently, the highest temperature rating is 240 ℃, with excellent resistance to radiation and chemicals.

　　Preferred for extreme environments such as aviation, aerospace, defense, and nuclear power—but comes with high costs and dark colors.

　　5) Polyamide-imide enameled wire (International common abbreviation: AI/AIW / Domestic national standard code: QXY)

　　With a temperature rating of 200–220℃, the national standard GB/T 6109.9 specifically establishes criteria for polyimide-polyamide enameled round copper wire. This type of enameled wire combines advantages such as high and low-temperature resistance and radiation resistance, and is often used as the outer layer in composite enameled wires. It finds applications in automotive ignition coils and motors operating in high-temperature environments.

　 　6) Self-adhesive enameled wire (International marking: Two common approaches are used. One is to append the abbreviation SB (short for Self-bonding) as a suffix; in some cases, SEW is also used. Domestic marking: There is no specific universal abbreviation for self-adhesive enameled wire in China. Instead, additional markings are added based on the corresponding national standard code for the underlying enameled wire. For example, certain models may include “HB” to indicate their self-adhesive properties. For instance, a 180-grade self-adhesive straight-welding polyester-imide enameled copper round wire can be marked domestically as QZYHB/180.)

　　The outer layer features a hot-melt adhesive coating (epoxy or polyamide); after heating, the coil self-forms.

　　Eliminates the varnish dipping process, suitable for ultra-small motors, hollow-cup motors, and mobile phone vibration motors.

　 　7) Fluororesin-insulated enameled wire: FIW The corresponding term is (full English name: Fluoropolymer Insulated Wire or Fluororesin Enameled Wire). At its core, this refers to a special type of enameled wire that uses fluorine-based resins as the insulating coating. It is not a single resin type but rather a collective term encompassing the entire family of fluororesins. FIW is the internationally recognized abbreviation for fluororesin enameled wire; there is no direct, single standardized designation for it in China’s national standards. Typically, specific fluororesin types and their performance characteristics are indicated alongside the term (e.g., “Fluororesin Enameled Wire (FEP)/200℃”). Nevertheless, FIW remains the universally accepted identifier used in international communications.

　　Core insulating materials: Common fluoropolymers include PTFE (polytetrafluoroethylene) and FEP (fluorinated ethylene propylene copolymer).

　　PFA (perfluoroalkoxy resin) and other such materials impart the core characteristics to enameled wires.

　　Core performance advantages:

　　High temperature resistance: The long-term operating temperature typically ranges from 150℃ to 260℃ (specifically depending on the type of fluoropolymer used);

　　Chemical corrosion resistance: Highly resistant to harsh chemical environments such as acids, bases, and organic solvents;

　　Low friction and wear resistance: Fluororesin boasts excellent surface properties and superior mechanical abrasion resistance.

　　Stable electrical insulation: Maintains excellent insulation performance over a wide temperature range and in harsh environments.

　　Common application scenarios: Due to their exceptional resistance to harsh environments, these materials are frequently used in fields that demand extremely high insulation performance and environmental adaptability, such as aerospace, new-energy vehicles (components for high-temperature areas), specialized motors/transformers, chemical equipment, and electronic instruments (in applications requiring resistance to chemical corrosion).

　　Difference from other abbreviations:

　　Unlike the previously mentioned single-resin enameled wires such as EIW (polyester imide) and UEW (polyurethane), FIW is a general term for “fluororesin-based” wires.

　　In some cases, the specific fluororesin type or temperature rating will be added after FIW—for example, FIW/PTFE 200 (PTFE material, 200℃ grade).

　　II. By Conductor Shape

　 　Round wire: Universal, simple winding process

　　 Flat wire: The slot fill factor can be increased from 40% to over 60%. Under the same volume, this results in higher power/torque, making it a mainstream solution for new-energy drive motors and high-efficiency transformers.

　 　III. By Conductor Material

　 　Copper wire: Highest conductivity, good weldability

　 　Aluminum wire: Lightweight and low in price, but with a conductivity of 61% IACS, requiring an increased cross-sectional area; suitable for applications where weight is critical and heat dissipation conditions are favorable (such as air-conditioning motors and certain transformers).

　 　Copper-clad aluminum, copper-clad steel, and other alloy wires Balances conductivity and cost, suitable for audio coils and high-frequency signal lines.

　　4. By heat resistance temperature class (IEC/GB standard)

　　90 ℃ (Y) → 105 ℃ (A) → 120 ℃ (E) → 130 ℃ (B) → 155 ℃ (F) → 180 ℃ (H) → 200 ℃ (C) → above 220 ℃. When selecting a model, the rule of “every one-degree increase in temperature doubles the service life” is often used for quick estimation.

　 　V. Special Function Type

　 　Corona-resistant wire: Nanoparticle-modified polyimide for high-power-density motors powered by variable-frequency drives

　 　Refrigerant-resistant cable: Composite topcoat resistant to R134a and R410a refrigerant oils, specifically designed for compressors.

　 　Colored thread: Polyurethane is easy to dye and facilitates the identification of multiple fiber bundles.

　 　Summarize in one sentence.

　　For enameled wire, first select the temperature rating based on application requirements, then choose the insulation varnish system and insulation specifications. Finally, consider the conductor material as well as size and shape requirements. If special functions or non-standard insulation requirements are needed, a customized solution should be considered.

　　For ordinary motors, use QZ polyester at 130℃;

　　QZY for automotive/industrial applications at 180℃;

　　Inverter compressor, new-energy-driven, Q(ZY/XY) composite for 200℃ applications;

　　For aerospace and military applications, use QY polyimide at temperatures of 220℃ to above 300℃.

　　Need direct soldering, color, fine wire—priority QA polyurethane;

　　If you want to eliminate varnish dipping and increase the slot fill factor, choose self-adhesive wire or flat wire.

　 　In addition to the aforementioned enameled wire, there are also high-end extruded wires such as PEEK.

　　In addition, currently, all of the aforementioned enameled wires are solvent-based and non-environmentally friendly; they merely meet environmental requirements such as ROHS and REACH.

　　The abbreviation for the “Directive on the Restriction of the Use of Certain Hazardous Substances in Electrical and Electronic Equipment.” In the field of enameled wires, RoHS certification is a commonly recognized environmental standard. Enameled wires that meet this standard limit the content of hazardous substances such as lead, mercury, and cadmium. For example, polyester enameled copper wire certified under RoHS, due to its environmentally friendly properties, can be used in windings for various types of electrical and electronic equipment, making it suitable for production environments with high environmental requirements.

　　Author: Product Application Technology Department, Zhituo Commerce (Guangzhou) Co., Ltd.