There is a clear technological gap between common mode inductor head manufacturing enterprises and decentralized manufacturers, which is reflected in three hard indicators: process accuracy, material consistency, and mass production stability. The head is not unable to produce low standard products, but has a much better ability to control parameter deviations during mass production than decentralized manufacturers.
1, Differences in precision of core process control
Winding process: The head adopts a fully automatic CNC winding machine, and the inter turn spacing error is controlled within ± 0.05 turns to avoid inter turn short circuits; Distributed winding is mostly semi artificial, with an error of over ± 0.2 turns, and resonance loss anomalies are prone to occur at high frequencies.
Magnetic core insulation treatment: The head is treated with vacuum high-voltage immersion paint+130 ℃ constant temperature baking for 2 hours, and the adhesion of the insulation layer meets the standard; The dispersed type is a simple immersion paint under normal pressure, and the insulation layer is prone to peeling off, resulting in excessive leakage current under high temperature conditions.
2, Consistency differences in material parameters
Magnetic core material: The head is made of certified nanocrystalline/manganese zinc ferrite (in accordance with GB/T 1019-2013 standard), and the fluctuation of magnetic permeability is controlled within ± 3%; Distributed recycling of miscellaneous materials or non-standard magnetic powders results in magnetic permeability fluctuations exceeding ± 15%, leading to unstable common mode rejection ratio.
Wire selection: Use tin plated copper wire that meets the GB/T 3956-2008 standard for the head, with a wire diameter deviation of ± 0.01mm and a resistance deviation of ± 2%; Distributed non-standard copper wire with wire diameter error exceeding ± 0.03mm and resistance deviation exceeding ± 8%, directly affecting the accuracy of inductance.
3, Differences in mass production stability
Batch qualification rate: The head is stable at 99.5% or above, and the non-conforming product rate is less than 0.5%; Distributed products are mostly between 90% and 95%, and non-conforming products can easily cause equipment EMC failure.
Adaptability to working conditions: The head product can operate in an environment of -40 ℃~125 ℃, with a saturation current attenuation rate of ≤ 5%; Distributed products can only adapt to -10 ℃~85 ℃, with a saturation current attenuation of over 10% at high temperatures, which cannot meet the requirements of industrial grade equipment.
