Bare copper flat wire


Rectangular-section bare conductors made from high-purity oxygen-free copper, with no insulation layer, exhibit outstanding electrical conductivity, thermal conductivity, and mechanical strength. Available in thicknesses ranging from 0.8 to 12 mm and widths from 3 to 25 mm, these conductors can be custom-configured as multi-wire assemblies. They serve as the core base material for enameled, paper-insulated, and other types of insulated conductors and are widely used in transformers, reactors, motor windings, busbars, and other applications.

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Bare copper flat wire
  • Bare copper flat wire

Product Description


This product is suitable for the windings of transformers, electric motors, and other electrical equipment.

Product VarietiesProduct ModelProduct Specifications
Soft Copper Flat WireTo Be Reviewed0.80 mm ≤ a ≤ 12 mm 
3.00 mm ≤ b ≤ 25 mm 
(a—narrow dimension of the conductor) 
(b—width dimension of the conductor)
Semi-rigid copper flat wireTBY 1/2
Hard copper flat wireTBY1, TBY2
Implementation StandardGB/T 5584 and the Technical Agreement between the Two Parties

 

 

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Product Advantages


Leveraging more than two decades of technological expertise and industry-leading manufacturing capabilities, the company has developed core product advantages characterized by high electrical conductivity, low loss, corona resistance, and exceptional reliability. By employing high-purity oxygen-free copper and state-of-the-art insulation processes, the products deliver outstanding mechanical and electrical performance, meeting the stringent requirements of high-voltage transmission and transformation applications as well as emerging sectors such as new-energy vehicles. This comprehensive approach enhances equipment operational efficiency, extends service life, reduces overall energy consumption, and provides customers with a stable, efficient, and secure one-stop electromagnetic wire solution.

Higher electrical conductivity


● Excellent electrical conductivity and low copper losses, enhancing motor efficiency and service life.
● Hongyuan Company Standard: Copper purity ≥ 99.99%, resistivity at 20°C ≤ 0.01710 Ω·mm²/m.

Control measures: High-purity Class A copper plates are self-cast to ensure excellent electrical performance.

Lower oxygen content


● Low oxygen content ensures high welding quality, thereby extending the service life of the motor.
● Hongyuan Company Standard: Oxygen content < 8 ppm.

Control measures: High-quality Grade A copper plates are self-drawn and cast, and process technical requirements are established for the charging frequency of electrolytic copper plates, smelting temperature, cooling rate, and protective measures during the melting process in the upward-drawing production process, to ensure that the copper rods have high purity and low oxygen content.

Smaller fillet radius


● A smaller fillet radius results in a higher packing density and higher motor efficiency.
● Hongyuan Company Standard: Minimum corner radius of 0.30 mm.

Control measures: Molds are manufactured using precision CNC technology and inspected with a projector, ensuring that the round-corner radius deviation is within ±10%.

Smaller coating film eccentricity


● The smaller the eccentricity, the more uniform the coating film and the better its electrical properties, such as corona resistance.
● Hongyuan Company Standard: Coating film eccentricity: maximum thickness/minimum thickness ≤ 1.3.

Control measures: Maintain optimal baking temperature, varnish bath temperature, and viscosity; conduct projection inspection on both bare-wire molds and coating molds to ensure that the fillet radii are properly matched, thereby guaranteeing uniform coating.

Better film flexibility and adhesion


● Excellent flexibility and adhesion to prevent cracking of the coating at the ends during bending.
● Hongyuan Company Standard:
Film flexibility: The coating film shall not crack when rolled up to twice its original thickness and twice its original width.
Coating adhesion: After cutting and stretching by 15%, the distance at which the coating loses adhesion shall be no greater than 0.5 times the conductor width.

Control measures: Employ the optimal painting process and precisely control the thickness of each paint layer.

Higher partial discharge inception voltage (PDIV)


● The higher the PDIV value of the winding, the longer the insulation system’s service life under aging conditions.
● Hongyuan Company Standard: Single-coat film thickness of 0.13 mm, PDIV (Vp) ≥ 1900 V.

Control measures: use PI varnish with a low dielectric constant, increase the varnish film thickness, and enhance the degree of varnish curing.

Higher corona resistance


● Enhancing corona resistance can reduce partial-discharge-induced coating degradation, thereby extending the service life of electric motors.
● Hongyuan Company Standard: Single-coat film thickness of 0.12 mm, corona resistance life ≥ 500 hours.

Control measures: modify the properties of the insulating varnish, increase the coating thickness, reduce coating eccentricity, and enhance coating cure.

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