Advantages of square copper wire coils compared to round copper wire coils

01 Higher area ratio, reduced skin effect

Increased volume utilization and high slot fill rate after winding result in reduced self-resonance of the coil. Compared to round wire coils, square and flat wire coils achieve a 27% increase in volume utilization.

The phenomenon where current flows along the surface of a wire at high frequencies is called the skin effect. Since the surface area of a square wire of the same size as a round wire is larger, it effectively reduces the skin effect at high frequencies.

※For example, for a round wire with a diameter of p1.0mm and a circumference of 3.14mm, the circumference of a square wire with dimensions 1.0x1.0mm is 4mm, which is 1.27 times that of the round wire.

02 Advantages of thermal conductivity (heat dissipation advantages)

Typically, after winding, round wires make point contact with each other, and the space between the wires actually enhances heat insulation. Square wires, on the other hand, make surface contact with each other without any space between them, resulting in better heat dissipation.

03 Save space and reduce material costs

When setting the square wire coil to the same resistance value as the round wire coil, the square wire diameter can be thinner. If the round wire diameter is 0.45 mm, then the square wire can be 0.40 mm x 0.40 mm. This allows the overall coil to save space, which in turn reduces the size of related parts, saves space in the entire machine, and lowers product costs.

04 Improved electrical performance

Comparison of round wire and square wire of the same size

(e.g., round wire 1.0 mm vs. square wire 1.0 mm x 1.0 mm)

Considering that the cross-sectional area of round wire 1.0 is 0.785 mm², the cross-sectional area of square wire is 1.0 mm². When compared under the same voltage/current conditions, the resistance value of square wire coils can be reduced by over 15%. A reduced resistance value means the coil can handle stronger currents and voltages, offering an advantage in terms of achieving higher power output. Additionally, a reduced resistance value can effectively control electrical energy loss caused by heat dissipation, providing an advantage in energy savings, and can also effectively control self-generated heat.

Applied voltage 12V 1.0A for 30 minutes

With the same number of turns, the coil temperature is 33°C lower than that of round wire. Even if the number of turns is increased by 100, the coil temperature is still 27°C lower than that of round wire (with similar resistance values).