Energy-efficient VSDs are becoming increasingly popular in a host of industrial machines, systems and equipment. The use of VSDs is particularly economical when different power levels are required in response to variable demand. However, frequency regulation calls for bearings that fit a different set of requirements, largely because there is always the risk of parasitic current reaching the driven components via the motor shaft and bearings. This current can cause damage to the bearings from phenomena such as ripple formation and the melting of running surfaces. The function and service life of driven components can also be impaired by the passage of current.
Design engineers are able to counteract these relatively common problems by using deep groove ball bearings with a ceramic coating on the outer ring. The insulating effect of the coating stops current transfer and, subsequently, prevents bearing damage.
Based on an extensive series of tests, NSK has enhanced the ceramic coating used until now, a move that has resulted in two prime advantages. Firstly, the insulating effect of the coating is up to 10 times greater. Secondly, the impact resistance of the normally very brittle ceramic is now more than three times that of ceramic coatings found on conventional bearings. The bearings thus achieve significantly longer service life.
A further benefit is that the optimised ceramic coating provides better dissipation of the heat generated in the bearing as rotation occurs, again contributing to extended service life.
NSK’s range of ceramic-coated deep groove ball bearings is described in a new catalogue entitled ‘Bearings for Electric Motors’, which is available in print or as a PDF download at: http://www.nsk-literature.com/en/industrial-motor-bearings/
NSK Europe Ltd. is the European organisation of the Tokyo-based bearing manufacturer NSK, which was founded in Japan in 1916 and today employs nearly 31,000 people in its worldwide operations. The products and solutions provided by the industrial and automotive supplier can be found wherever things move. In addition to nearly all types of rolling bearings, the company’s portfolio includes housed bearings, linear technology, wheel bearing units, transmission and engine bearings and steering systems. The company is oriented to perfection in all of its business activities. Its aim is quality leadership in its industry, which it strives for through a continuous process of improvement, excellent product development, optimised production processes and customer-oriented service processes. In fiscal year 2019, the more than 4,400 employees of NSK Europe Ltd. generated sales of over € 920 million.
NSK Deutschland GmbH
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