Press Release Summary:
Available in standard sizes with outer ring diameters from 80-400 mm, Electrically Insulated Rolling Bearings prevent passage of electric currents through bearings, protecting against electro corrosion. Units with oxide ceramic insulating layer have guaranteed minimum breakdown voltage of 1,000 Vac or Vdc. For smaller bearings, rolling elements made of oxide ceramic can be used. Load ratings, boundary dimensions, and tolerances are identical to standard bearings.
Original Press Release:
Electrically Insulated Bearings Prevent Damage By Electro Corrosion
Steyr, Austria, August 2007. Bearing manufacturer NKE Austria offers electrically insulated rolling bearings in standard sizes and in different design variations. Electrically insulated bearings provide optimal protection against bearing damage caused by electro corrosion.
For modern electrical machines with high degrees of performance, and demanding reliability and service life, equipment failures by electro corrosion can cause significant problems. Under unfavourable operating conditions, bearings in electrical machines can 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.
NKE Austria offers electrically insulated rolling bearings in standard sizes with outer ring diameters between 80 mm and 400 mm. 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 1000 V 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.
NKE Austria GmbH is a bearing manufacturer with headquarters in Steyr, Austria. Founded in 1996 by a group of senior staff members of former company Steyr Wolzlager, NKE offers both standard and special bearings for all industrial applications. NKE's core functions - engineering, product development, final processing of components, assembly, quality assurance, logistics, and sales and marketing - are centralized at its Steyr headquarters. The site is accredited to ISO 9001:2000 (design, development, production and distribution of bearings) and ISO 14001:2004. Its wide range of standard bearings is available from stock or at short production lead-times. It also provides tailored products and solutions. In addition to product and application development, NKE also provides a full range of technical services, consulting, documentation and training. NKE's products are distributed through 15 international representative offices and more than 240 distribution outlets in 60 countries.
NKE AUSTRIA GmbH
Ms. Janet Mo, Marketing
Ennser Str. 41a
A-4407 Steyr-Gleink, Austria
Tel: +43 7252 8666 7345
Fax: +43 7252 8666 759
Contact in the USA:
NKE AUSTRIA GmbH, US representative office
Mr. Dick Scott
20 Barney Road, P.O. Box 5255 Clifton Park,
New York 12065
Tel: 518 371 5759 Fax: 518 383 6487