Technology supplier MAHLE has developed what it terms as the most durable electric motor currently available in the market. It is a traction motor design featuring a new cooling concept which enables the motor to operate under high load indefinitely.
Known as the superior continuous torque (SCT) E-motor, it can be used in a range of mobile applications including passenger cars, commercial vehicles, and heavy-duty off-road equipment such as agricultural and construction equipment.
“Building large electric motors that deliver short-term high performance is easy. What was still lacking on the market until now were durable yet compact drives to make electric vehicles unrestricted for everyday use,” said Martin Berger, Vice President Corporate Research and Advanced Engineering at MAHLE, in the company’s press release announcing the launch of the electric motor. “Our new SCT E-motor is the solution.”
Additional features of the SCT E-motor include its clean, lightweight and efficient design as well as the ability for customers to request it be assembled without the use of rare earth metals.
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Creation of a Long-Lasting, High-Performance Motor
According to MAHLE, the SCT E-motor is designed to be particularly efficient within a certain rpm. Torque is provided continuously over the complete operating range of the motor which is unprecedented with previous electric motors said Berger during a media briefing on the new SCT E-motor.
Previously, about 50-60% of peak torque for a motor was available for 50-60 seconds before needing a break for “thermal relaxation” he said. But with the new motor users can expect continuous operation at 90% peak torque. This enables the motor to be used as a replacement for combustion engines in a range of vehicle applications including those deployed in demanding environments.
Berger provided the example of a heavy truck ascending a steep incline. If the truck is equipped with the SCT E-motor, the driver can feel confident it will easily reach the top of the hill or mountain because of the continuous high-power capabilities provided by the motor.
Use of an integrated oil cooling technology is a key factor to the SCT E-motor’s durability and operational longevity. The oil cooling ensures continuous high-power capabilities and robustness as well as the ability to dissipate waste heat to other parts of the vehicle to make the heating system more efficient said Dr. Harald Straky, Vice President Product Development Electronics & Mechatronics at MAHLE, during the media briefing.
“I am convinced that this motor is not only a milestone and a technological leap, but it is also a firm pillar in our transformation for e-mobility,” he said.
The SCT E-motor is a permanently excited motor which MAHLE said in its press release helps to enable a compact design. In addition, this motor type eliminates the need to transfer energy to the rotor as excitation current, aiding its efficiency and wear-free design. Neodymium magnets are utilized to generate the magnetic field within the motor and are considered to be the strongest permanent magnets produced.
However, a magnet-free design is also possible to minimize use of rare earth materials. Instead of magnets in the rotor, copper is utilized as well as MAHLE’s contactless transformer which replaces the carbon brush to ensure a wear-free and efficient design said Straky.
The contactless transformer was first introduced with the magnet-free electric motor MAHLE unveiled in May 2021. Similar to the magnet-free version of the SCT E-motor, the previously introduced motor transmits electric currents between rotating and stationary parts within the motor without any contact. This eliminates the chance of wear, ensuring a more durable motor.
MAHLE has provided the SCT E-motor to a few customers whom Straky said have shown a high level of interest in the technology. The company plans to present its newest electric motor to the public for the first time during IAA Transportation 2022 (formerly known as IAA Commercial Vehicles), a global event focused on the entire commercial vehicle, logistics and transport sector taking place September 20-25 in Hannover, Germany.
