Posted to News on 26th Sep 2013, 10:52
Ceramic-coated Electro-Safe bearings from Revolvo
Revolvo - which describes itself as the UK's leading specialist bearing manufacturer - has developed a new range of ceramic-coated deep groove ball and cylindrical roller bearings, which protect against the damaging effects of electrical erosion in rotating equipment such as railway traction motors. Available in bore sizes up to 750mm, the bearings are intended for use anywhere that electrical current could otherwise cause premature failure to the bearing.
Revolvo's ceramic-coated bearings help equipment such as traction motors to achieve an extended lifetime, overcoming the problem of electrical erosion which occurs when "stray' electric current flows through the motor bearings to earth. The extent of the damage which this current flow can cause depends upon the magnitude of the current and the duration of the conditions.
Damage usually takes the form of parallel axial marks, known as "fluting" in the areas of contact between the raceways and the rolling elements. Other more damaging effects of the current are craters, sometimes accompanied by a dark brown discolouration, which occurs in the trackways and this leads to premature bearing failure.
Revolvo's solution to this problem is to coat the external surfaces of the bearing outer ring with aluminium oxide, using a plasma spraying method. To enhance the adhesion of the ceramic material to the bearing steel, a bond coat compound is first applied. The final minimum thickness of the ceramic coating is 0.3mm, enabling the bearings to cope with direct voltages up to 1000V DC.
This high-quality coating is able to withstand press fitting forces without damage, and no dimensional modifications of the bearing housing are necessary, as the dimensions and tolerances of the insulated bearing are identical to those of the standard bearing. Revolvo is capable of manufacturing insulated bearings with bore sizes of up to 750mm, making them suitable for applications across many industries.
Adrian Menzies, Sales and Marketing Director for Revolvo, comments: "Premature bearing failure caused by stray electrical currents can be extremely frustrating for site operators within certain industries. Often, thinking that it is unavoidable, they will sometimes specify low-grade bearings to reduce the cost of frequent replacement, which just exacerbates the original problem of premature failure.
"At Revolvo we believe it is our responsibility to develop solutions for our customers' problems which is why we developed the "Electro-Safe' insulated bearing. Its ceramic coating protects it from damaging electrical currents and ensures the bearing performs reliably for its predicted life span."
To learn more about Revolvo's ceramic-coated Electro-Safe bearings please go to www.revolvo.com.
