Innovating an industry with proven expertise

Nomex® has fueled the electric insulation industry with design, expertise and evaluation technology. It’s why Nomex® is trusted around the world to help meet the harsh operating conditions in EVs/HEVs. 

With its high-temperature durability, superior mechanical strength and unparalleled chemical stability, Nomex® is the material of choice to improve performance in motors and generators and prevent premature failures.

Exceptional thermal stability

Nomex® has an Underwriters Laboratories (UL) thermal rating of 220°C and a long history of proven endurance under high thermal stress. This high-temperature durability helps to allow miniaturization and/or higher power density of electrical drive motors and enables long-term electrical dependability.

This also helps OEMs to reduce the size and weight of components such as traction motors, which in turn can increase fuel efficiency.

The effects of long-term exposure to high temperature on important electrical and mechanical properties of Nomex® are shown in Figures 1 and 2.

Superior mechanical strength

The superior mechanical strength and resilience of Nomex® insulation (refer to Table I) help extend the service life of rotating equipment, such as traction motors, which are subjected to harsh operating conditions that include severe shock and vibration, as well as abrasion caused by thermal expansion and centrifugal forces.

An added benefit of the superior mechanical strength of Nomex® is the manufacturing efficiencies that can be gained from automatic insertion of slot liners.

Nomex® has a long history as an electrical insulation material of choice for traction motors, automotive motors and automotive generators due to its proven performance and reliability. Based on its track record of helping OEMs around the world to improve performance and prevent premature failures in these applications, OEMs are now choosing Nomex® to help them meet the increased power density requirements and harsh operating conditions of motors and generators used in electric vehicles (EVs) and hybrid electric vehicles (HEVs).

Excellent dielectric strength

Nomex® features excellent electrical properties and endures electrical stresses that are commonly encountered in electric vehicles (EVs) and hybrid electric vehicles (HEVs) due to the use of inverters. As shown in Table II, Nomex® has excellent dielectric strength. It is important to note that these values differ from long-term strength potential. DuPont recommends that continuous stresses in transformers not exceed 1.6 kV/mm 

(40 V/mil) in order to minimize the risk of partial discharges (corona). DuPont has materials designed for applications where corona is present, should this be necessary.

Excellent chemical stability

Experience in similar types of automotive motors and generators over the past decades has proven that Nomex® is compatible with a wide range of chemicals, including virtually all classes of electrical varnishes and adhesives, as well as the oils and automatic transmission fluids often used in EVs and HEVs. 

Design and testing expertise

As a leader in electrical insulation systems for more than 50 years, DuPont has earned a strong reputation for evaluating the performance of insulation used in equipment. Our experts are drawing on this experience to help global OEMs translate their performance needs into measurable criteria, even designing new test protocols and testing equipment when necessary.

DuPont experts in motor design are also working with top OEMs around the world to help them develop specific solutions that will optimize their motor designs and help advance this evolving industry.