BEARINGS BASICS Q&A: IN CASE YOU DIDN’T KNOW…

Wind turbine gearboxes are subjected to a wide variety of operating conditions, some of which may push the bearings beyond their limits. Damage may be done to the bearings, resulting in a specific premature failure mode known as white etching cracks (WEC), sometimes called brittle, short-life, early, abnormal or white structured flaking (WSF). Measures to make the bearings more robust in these operating conditions are discussed in this article.

For Mark Findlay of UK specialist driveline consultancy Drive System Design, reducing gear noise to suit the low noise levels in an electric vehicle cabin has meant throwing away the rule book.

News about new Products in the industry.

Electric motor-driven systems are the single largest enduser of electricity, accounting for over 40% of global consumption according to the International Energy Agency.

If you read only one article this issue, it should be Norm Parker’s article on the Chinese bearing manufacturing industry. Parker is an engineer with General Motors, a true industry insider who has become a regular contributor to Power Transmission Engineering.

The complete technical Calendar from the September 2014 issue of Power Transmission Engineering.

University lab's motor eliminates pricey rare-earth magnets.

Varying installation requirements for worm gears, as, for example, when used in modular gear systems, can necessitate grease lubrication - especially when adequate sealing for oil lubrication would be too complex. Such worm gears are being increasingly used in outside applications such as solar power plants and slew drives. While knowledge about the operating conditions is often appropriate, the basic understanding for load capacity and efficiency under grease lubrication is quite poor. Investigations done at FZG and sponsored by FVA/AiF are shown here to give an impression of the basic factors of load capacity and efficiency. The results of the investigation indicate a satisfying quality of calculations on heat, load capacity and efficiency based on characteristic parameters of the base oil with only slight modifications to the methodology known from DIN 3996 or ISO TR 14521.

The growth of worldwide energy consumption and emerging industrial markets demands an increase of renewable energy shares. The price pressure coming from coal, oil, nuclear and natural gas energy - combined with enormous worldwide production capacities for components of wind turbines - make wind energy a highly competitive market. The testing and validation of gearboxes within the test rig and the turbine environment attract a strong focus to the needs of the industry. The following contribution sums up the typical process requirements and provides examples for successful system and component verifications based on field measurements.