Grundfos is able to offer a solution to their customers who experience issues with the bearings in their electric motors. The solution is CeramicSpeed LongLife Insulate bearings, which improve reliability significantly. The bearings are guaranteed to prevent the passage of electrical currents through the bearing, and have a lifetime which is significantly longer than other bearings on the market.

Grundfos
With an annual production of more than 16 million pumps, Grundfos is one of the world’s leading pump manufacturers. Grundfos’ main products include circulator pumps for heating and air conditioning, as well as pumps for industrial use, water distribution and wastewater. Grundfos is the world’s largest producer of circulator pumps, covering approximately 50% of the global market.

Frequency converters
Leading motor manufacturers agree that stray currents can cause damage to bearings in frequency controlled motors. Various attempts have been made to solve this problem. A typical solution is to install a bearing with an insulated coating on the non-drive side. Insulated bearings aren’t always used in smaller motors; however stray currents can cause damage in motors as small as 1-2 kW.

Bearings with ordinary steel balls are extremely sensitive to electrical currents. A thin coating can be applied, which provides an insulating property of up to 1 kw. Hybrid bearings have an insulating ability of at least 2.5kW on smaller bearings, and much higher on larger bearings.

The insulating effect is provided by the properties of the CeramicSpeed balls themselves, rather than a coating. This makes the bearing much easier to handle, as the risk of damaging the coating during installation is removed.

The optimal solution in order to avoid bearing failure and production downtime is to install hybrid bearings on both the drive and non-drive side. In addition to preventing the passage of electrical currents, this will reduce the operating temperature by 10-20 degrees and increase the bearing lifetime by 4-8 times in comparison with ordinary steel bearings. Coated bearings can also prevent the passage of electrical currents, but they don’t extend the bearing lifetime or reduce friction, and are only available in a limited range of models.