Carbon solutions for the electric powertrain

Electric powertrains (automotive)

Whether it's protecting against inverter-induced shaft voltages or transferring current reliably to a rotor. In electric powertrains for automobiles, our carbon components perform three very different but equally critical functions. Find the right solution for your application below.

Shaft Grounding (Automotive)

Carbon protects electric motors from inverter-induced currents

As powertrain electrification advances, shaft grounding is becoming critical in automotive applications as well. Modern silicon carbide (SiC) inverters switch at very high frequencies – a physical effect that generates capacitively coupled shaft voltages in the electric motor. If these parasitic currents aren't specifically discharged, they travel through the motor bearings or gearbox components, resulting in bearing corrosion, pitting damage, premature bearing failure, or impermissible noise generation in the gearbox.

Schunk's grounding systems with carbon contact elements are specifically qualified for automotive use. They safely dissipate shaft voltages up to the 100 MHz range – even in an oily environment – without requiring major structural changes to the motor architecture. They also deliver excellent results when it comes to optimizing electromagnetic compatibility (EMC) in your drives – a topic of growing importance, particularly with the use of SiC semiconductors.

Special requirements in automotive applications

Automotive applications differ from industrial use cases through:

More compact installation spaces

Higher vibration loads

Wide temperature ranges (cold start to high-load operation)

Dissipation capability up to the 100 MHz range

IATF 16949 qualification requirements of the automotive industry

Schunk Carbon Technology brings both materials expertise and manufacturing know-how tailored to automotive applications.

Typical automotive applications

Electric motors in electric and hybrid vehicles (BEV, HEV, PHEV)

E-axles and electric drive units

HV starter-generators for hybrid vehicles

Electric pumps and compressors with SiC inverter controls

Auxiliary drives with high-frequency inverters

Power Transmission Systems for EESM

Reliable power transmission for externally excited synchronous motors

Externally excited synchronous motors (EESM) are gaining traction in automotive applications – primarily because, unlike permanent-magnet synchronous machines, they don't rely on rare earth materials. The trade-off: the excitation field in the rotor needs to be actively supplied with current. This excitation energy must be reliably transferred from the stationary stator side to the rotating rotor – continuously, with minimal wear, and under demanding vehicle operating conditions.

Our wet-running power transmission system is designed exactly for this task. It transfers the excitation current to the rotor shaft via a contact-based design, specifically engineered for operation within the oil circuit – a decisive advantage as modern e-drives are increasingly oil-cooled. The carbon materials used stand out for low wear, stable contact resistance, and high service life, even at high rotational speeds and under changing thermal conditions.

Coil carrier for the stator

Beyond power transmission to the rotor, the stator-side winding also plays a critical role in the efficiency and service life of the EESM drive. Our coil carrier for the stator ensures precise positioning and reliable electrical insulation of the winding, while also providing good heat dissipation – essential for high power density in a compact installation space. As a carbon component, it's designed for series-production manufacturability and for the thermal and mechanical demands of automotive use.

The power transmission system and coil carrier complement each other: while one component ensures energy transfer to the rotor, the other supports reliable build-up of the stator field.