Amazing new electrically conductive synthetic lubricant will reduce bearing wear.

With this new electrically conductive synthetic lubricant electric motors will be protected from pitting that can result from an electrical discharge in the bearings. After years of research, a group of German basic and industrial engineers have finally made significant progress towards sustainable electromobility. The project was funded by the German Federal Ministry for Education and Research.


As part of an initiative to study future vehicle technologies which are expected to operate on higher voltages than current models. At the moment, 12 volts is the standard operating architecture to power everything from lights and radios to air conditioners. However with the increased level of electrification hybrid and micro-hybrid vehicles are expected to run on 48 volts, as electric power is required for a growing number of functions. The voltage levels of electric vehicles is even higher: these vehicles can require as much as 400 volts.

New electrically conductive synthetic lubricant are required to overcome strong alternating electric fields.

“In alternators and electric motors, higher voltage levels mean that alternating electric fields are stronger than they once were,” says Dr. Gerd Dornhöfer, one of the Bosch associates taking part in the “SchmiRmaL” project (Switchable intelligent tribological systems with minimal friction losses and maximum lifespan). This can result in electrical discharge in the ball bearings of motors and alternators. When this occurs, the resultant arcing could melt tiny areas of the metal’s surface causing pitting, resulting in uneven raceways.

The first signs of this would be ball bearing noise followed shortly after by complete failure. “We can already prevent this from happening reliably with the new electrically conductive synthetic lubricant we have developed,” says Dornhöfer, chief expert for lubrication technology at the research department in Gerlingen, close to Stuttgart.

New electrically conductive synthetic lubricant film acts as an insulator.

With higher voltages and static build-up from the current generated between the shaft and housing of an electric motor, the role of the lubricant coating in the bearing acting as an insulator gains importance. As rotation speed increases, the synthetic grease in the ball bearing insulates the bearing from the raceway. This is similar to aquaplaning on wet roads, and minimizes the friction generated by the bearings as well as reducing surface damage.

However, this can also lead the bearings to build up an electrical charge when the lubricant film is intact, similar to a capacitor. When the built-up voltage is high enough, it can discharge through the insulating lubricant grease. This energy is sufficient to begin an electrical corrosion of the bearings surface. If this continues tiny imperfections, in the form of pitting, eventually appear on the bearing. “We want to prevent this at all costs, as it can result in greater damage to these spots over time,” says the Bosch scientist.

Engineers refer to this as electrical pitting. The process results in damaged areas on the raceway that are comparable to potholes. In the future, the energy of these discharges may become greater as the power density and voltages of automotive electric systems increase, thereby requiring the development of a new electrically conductive synthetic lubricant.

In light of this potential problem, the SchmiRmal project’s strategy focuses on developing a new electrically conductive synthetic lubricant, whose base oils remain conductive even at higher voltages. As a result, these lubricants do not act as insulators to begin with. Voltage levels no longer build up, nor does potentially destructive electrostatic discharge.

There are several solutions to this problem:

For instance fine metal particle could be added to the grease to conduct the current. But this would mean that the lubricant grease would also act as an abrasive.

An alternative would be the use of ionic fluids. In chemical terms, these are molecules known as ions that conduct an electrical charge. “Ionic fluids conduct electricity, and this is why we add these substances to our lubricants,” said Dornhöfer.

The new electrically conductive synthetic lubricant has reduced electrical resistance.

Following several tests, the scientists developed greases that conduct electrons within the ball bearing thereby preventing electrical flashovers and arcing. The initial material was a commercially available industrial synthetic lubricant. “By using the right ionic fluids combined with conductive carbon, its resistance was reduced by a factor of ten million,” says the Bosch scientist.


While the new electrically conductive synthetic lubricant grease is black, it otherwise largely resembles its predecessor. At present, Dornhöfer is focusing in part on investigating all of the grease’s characteristics. To ensure a long life cycle the new electrically conductive synthetic lubricant must be heat resistant and have cold flow properties. Moreover, the new additives should not compromise the grease’s corrosion protection properties. And it goes without saying that the new grease should not pose a hazard to human health or the environment. All of this is currently being tested as part of the BMBF project. “So far, our findings have been very promising”, Dornhöfer says.

Many scientists from a broad range of disciplines and sectors have contributed to this success. “No one can find these solutions alone. We are all contributing and learning from one another,” Dornhöfer says. The project is set to run until April 2015. “Chances are high that the new lubricants will find industrial application after the project.”

New electrically conductive synthetic lubricant offers A longer service life for machine components.

The benefits of the project’s work go beyond applications for electric motors. The new electrically conductive synthetic lubricant can also increase the service life and reliability of machine elements that experience high levels of strain, especially roller and plain bearings and transmission components. Moreover, performance can be improved for motors of the same size, or maintained if motors are smaller. At the same time, the lubricants contribute to reducing energy consumption and to increasing efficiency.

While the new electrically conductive synthetic lubricant may still be some way from commercial production high quality synthetic lubricants are available immediately fro quality lubricants manufacturer Habot Oil. Cal them now to get more information on which lubricants are best for your machinery and equipment.