Insulated bearings prevent electro corrosion

Electrically insulated rolling bearings are integrated with an efficient electrical insulation that prevents the passage of electric currents through bearings, increasing reliability and service life.

For modern electrical machines with high degrees of performance, and demanding reliability and service life, equipment failures by electro corrosion could cause significant problems.

Under unfavourable operating conditions, bearings in electrical machines could be damaged by the passage of electrical currents.

Such a passage of current can be caused by faulty or damaged insulation of the bearing shields or an ineffective earth connection of the machine.

The appearance and the degree of electrical damage of bearings depend on the individual operating conditions, e g, the actual effective voltage.

The machinery user may notice this process only by symptoms, such as increased running noise or vibrations, until the bearing fails prematurely.

The appearance of the damage may vary from visually detectable single craters and to fluting with discolorations around the affected areas.

In most cases, the effective electrical insulation of the end shields entails extra costs and efforts.

For existing designs, the improvement of electrical insulation could be technically complicated.

The simplest solution is to use electrically insulated rolling bearings, which are integrated with an efficient electrical insulation that prevents the passage of electric currents through the bearings.

Consequently, the additional electrical insulation of the end covers can be omitted.

Besides saving costs, the means for the user also an increase in reliability and service life of the machines.

Bearing manufacturer NKE Austria offers electrically insulated rolling bearings in standard sizes with outer ring diameters between 80mm and 400mm.

Special sizes are available upon request.

The electrically insulated bearings are available in different design variations.

Bearings with an oxide ceramic insulating layer have a guaranteed minimum breakdown voltage of 1000V alternating or direct current.

The insulation coating is applied to the outer rings by plasma spraying method.

For smaller bearings, rolling elements made of oxide ceramic (silicon nitride) can be used.

The load ratings, boundary dimensions and tolerances of NKE electrically insulated bearings are identical to those of standard bearings, and therefore completely interchangeable with conventional bearings.

Electrically insulated bearings provide optimal protection against bearing damage caused by electro corrosion, and therefore enable significantly improved reliability of electrical machines compared to conventional bearings.

* About NKE Austria - NKE Austria is a bearing manufacturer with headquarters in Steyr, Austria.

The company was founded in 1996 by a group of senior staff members of former Steyr Waelzlager.

NKE offers both standard and special bearings for all industrial applications.

NKE's core functions - such as engineering, product development, final processing of components/assembly, quality assurance, logistics, sales and marketing - are centralised at its headquarters in Steyr, Austria.

The site is accredited with ISO9001:2000 (design, development, manufacturing and distribution of bearings), ISO14001 and EMAS (environmental management).

Its wide range of standard bearings is available from stock or with short production lead-times.

For special requirements, it can provide rapid, practical and creative custom-made solutions.

Moreover, NKE also provides full technical services such as product and application development, consulting, documentation and training.

The products are distributed through twelve international representative offices and more than 200 distribution outlets.

Back to top