In Germany, an oil-cooled car electric motor was created – it is difficult to overheat even during hard operation
The German company Mahle has developed an electric motor that can continuously work under a load of more than 90% of the peak. The Superior Continuous Torque (SCT) electric motor does not overheat in the vast majority of harsh operating modes. At the same time, it is compact and light, which also makes it cheaper. It is expected that the SCT electric motor will become the basis of passenger electric cars and heavy machinery on electric traction.
Conventional electric motors cannot work for a long time at loads close to the maximum – they simply overheat. It comes to the point that in electric cars, the long-term load on the electric motors does not rise above 50-60% of the peak load. In order to better cool the electric motor, it has to be made more massive — larger and heavier. In this way, you can increase the long-term load on the electric motor to 70-80%, but at a rather large cost both in money and by losing part of the payload (which will be eaten by the excess weight of the electric motor).
German engineers managed to develop a light and powerful electric motor that can keep a constant load of more than 90% of the maximum. A truck with such an engine will not die on a steep climb with a heavy load in the back, and a racing electric car will show miracles of work under load on the track.
The secret of the development lies in the automatic supply of oil for cooling. The oil is sucked in through the central intake and pumped around the coils due to the centrifugal force of the rotating rotor. Heated oil from the engine can be used to heat components and units of the electric vehicle, for example, the battery unit in winter, or it can be cooled through radiators.
Moreover, Mahle designers are developing an oil-cooled version of the electric motor without permanent (neodymium) magnets. Such electric motors will not depend on the supply of rare earth raw materials and will be cheaper, although due to the replacement of magnets with an electric winding, the motors will be slightly larger. We previously reported on this Mahle development.
