Hitachi Cable, Ltd. has announced the development and the full-scale production starting from May by Hitachi Magnet Wire Corp., a group company that manufactures magnet wires, of the world's first*1 inverter-surge-resistant rectangular polyamide-imide enameled wires for next-generation vehicles coated by varnish with high surge resistance*2 and heat resistance as an insulating film.

Demand is growing worldwide to reduce the environmental impact of vehicles. In response to global warming trends, various countries have enacted stricter regulations to reduce CO2 emissions, fuel consumption, and exhaust gas emissions. Additionally, expectations are growing for next-generation vehicles such as hybrid and electric vehicles, which incorporate the motor as a power source and inverters to adjust the motor output. These parts incorporate enamel wires.

The Hitachi Cable Group has developed heat-resistant, self-lubricating high-strength enamel wires that make it easier to build compact motors and achieve high motor output by improving the space factor of the enamel wire, as well as inverter-surge-resistant enamel wires offering superb surge resistance to contribute to longer motor service life and higher reliability. These products are used in many next-generation vehicles.

In accumulating various technological achievements, the Group realized the importance of enamel wires that offer excellent surge- and heat-resistance as well as a high space factor for improving motor reliability, reducing motor dimensions, and increasing motor output. The Group subsequently developed rectangular inverter-surge-resistant polyamide-imide enameled wires for next-generation vehicles coated with varnish offering high surge resistance and heat resistance as an insulating film, with full-scale production beginning in May.

The newly developed rectangular wires are made by covering the conductors with an insulating film made of surge-resistant polyamide-imide. The insulating film is a nanocomposite created by adding silica nanoparticles to polyamide-imide enamel varnish offering high heat resistance. The products offer improved surge resistance to partial discharge while retaining the superb characteristics of polyamide-imide enamel wires. A proprietary insulating film coating technology ensures uniform film thickness on rectangular, high space factor enameled wires for more stable electrical characteristics.

The Hitachi Cable Group will continue to focus on developing enamel wires with improved performance, with the goal of contributing to further advances in next-generation vehicles and expanding its business.

Reference : Lifetime characteristics (in no elongation state)

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Reference : Basic development concept

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Reference : Photo of surge-resistant polyamide-imide film taken by transmission-type electron microscope

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*1	The world's first commercially-available rectangular enameled wires (as of April 20, 2011); insulating film combines polyamide-imide enamel varnish and silica nanoparticles.
*2	Surge resistance refers to a characteristic that protects against transient partial discharge generated by high voltage resulting from the superimposition of a sudden surge at the rising edge of an applied voltage.