“New Ceramic Coated Insulated Bearings” for Wind Generators

Electrocorrosion (damage due to sparking from electric current flow in bearings) causes early raceway deterioration, and can especially be a problem in wind generator applications. Therefore, there exists a worldwide market demand for a reasonably priced insulated bearing to eliminate electrocorrosion. In some designs, an insulated coating is deposited on the bearing outer surfaces to prevent the flow of electricity and therefore eliminate electrocorrosion. However, when higher reliability is needed, such as in railway car generator applications, a higher-cost bearing with multiple insulation layers must be used.

NTN Corporation has developed a “New Ceramic Coated Insulated Bearing” with an insulation resistance of more than 100 MΩ and a dielectric breakdown voltage level of more than 2 kV, all at a cost of about half that of conventional insulated bearings. NTN's improved ceramic thermal spray method allows the thin structure of the insulator to be deposited in a single layer. This process also makes the sealed versions of NTN's ceramic coated insulated bearings ideal for use in inverter motor applications.

FEATURES

1. The unique ceramic material allows deposition of a single layer, thin coat structure at half the cost of conventional multilayer insulated bearings.
2. The thin, single layer insulator coating on the bearings provides a resistance of 100 MΩ and dielectric breakdown voltage level of at least 2 kV.
3. Sealed and shielded versions of the new insulated bearings are also available.

APPLICATIONS

Wind generators, inverter motors, general-purpose motors, railway car generators, etc.

SALES GOAL

300 million yen per annually (after 3 years)