Small wind turbines

Small wind turbines may be used for a variety of applications including on- or off-grid residences, telecom towers, offshore platforms, rural schools and clinics, remote monitoring and other purposes that require energy where there is no electric grid, or where the grid is unstable. Small wind turbines may be as small as a fifty-watt generator for boat or caravan use. Hybrid solar and wind powered units are increasingly being used for traffic signage, particularly in rural locations, as they avoid the need to lay long cables from the nearest mains connection point. The U.S. Department of Energy's National Renewable Energy Laboratory (NREL) defines small wind turbines as those smaller than or equal to 100 kilowatts.Small units often have direct drive generators, direct current output, aeroelastic blades, lifetime bearings and use a vane to point into the wind.
UWE bearing provide yaw, blade/pitch bearing and yaw bearing to our customers reliably. UWE wind turbine generator bearing is for 3KW-5MW wind turbine.Each wind turbine generator comprises of one yaw bearing and three pitch bearings, the material of the rolling rings is 42CrMo with quenching and tempering. Raceway surface intermediate frequency induction hardened. Due to complexity of the stress situation, the bearing must bear impact and carry high load. 20 years is a required lifetime for the wind turbine generator, it is also required by yaw bearing and pitch bearings as the mounting cost is too high.

UWE have self-develpoed hub for slewing ring testing

To make UWE slewing ring can work in perfect performance, we have self-developed hub to test slewing rings. We test every slewing ring before packaging, this could inspect if bearing could work with gear well, ball and spacer working performance,mounting hole precision and the torque changes..
For wind power, UWE keeps designing and developing.

Electricity from wind

Germany, the US, Spain, Denmark, India and Australia are among the world's leading nations in the acquisition of wind energy. Wind generated energy is growing in leaps and bounds.

Wind power is now the world's fastest growing energy source and has also become one of the most rapidly expanding industries, with sales of roughly $3 billion in 2008. Major offshore developments are likely in northern European waters in the early part of the next century.

This will be the next major step for this technology and will result in a dramatic increase in decentralized electricity generation. Offshore wind has the potential to deliver substantial quantities of energy at a price that is cheaper than most of the other renewable energies, as wind speeds are generally higher offshore than on land

As of 1999, global wind energy capacity topped 10,000 megawatts, which is approximately 16 billion kilowatt-hours of electricity. That's enough to serve over 5 cities the size of Miami , according to the American Wind Energy Association. Five Miamis may not seem significant, but if we make the predicted strides in the near future, wind power could be one of our main sources of electricity. "With today's technology, wind energy could provide 20% of America 's electricity (or about the amount nuclear power provides) with turbines installed on less than 1% of its land area. And within that area, less than 5% of the land would be occupied by wind equipment the remaining 95% could continue to be used for farming or ranching." By the year 2010, 10 million average American homes may be supplied by wind power, preventing 100 million metric tons of CO 2 emissions every year.

Bearings selection and calculations for wind power plants

The demands placed on bearings for wind power plants are extremely high. Therefore, the procedures for bearing selection and lifetime calculations are fundamentally different than selecting bearings in other application areas.
When selecting bearings for industrial use, design engineers can choose bearings for a defined bearing location relatively easily, working together with their suppliers if necessary, and basing their decisions on parameters such as rotary speed and torque, radial and axial load, and the required rigidity and preload or clearance. 
In wind power technology, the procedures leading up to the selection of a bearing are fundamentally different, essentially because of a single parameter: the bearing lifetime. The manufacturers of wind power plants and the gears for those plants require a bearing lifetime of 20 years (i.e. 175,000 hours) for their bearings. This is already an extreme value, but it does not cover all requirements. In addition, it must be taken into account that external loads acting on the bearing are highly dynamic (that is, irregular) because of the wind. The unfavorable environmental conditions for offshore facilities, used ever more frequently, are another factor: sea air is highly corrosive. For generator plants, electrical corrosion must also be taken into account. Finally, the service options available to wind farm operators are extremely limited, and any unscheduled downtime for a bearing will result in significant costs.

Slewing ring for wind energy

UWE is a leading Chinese supplier of blade bearing and yaw bearings for wind energy, from Small Wind Turbines of 750kW to the latest Multi-MW Offshore turbines up to 5MW.
The custom designed UWE slewing bearings are engineered in close cooperation with turbine manufacturers: our dedicated engineering team is at your service for new developments and design optimisation.UWE slewing bearings are delivered worldwide.

Materials for Sealing Ring of Slewing Ring Bearing

Materials for sealing ring of the slewing ring bearing usually is butadiene-acrylonitrile rubber SN7453, structure is often sealing in lip type. In places with the large discrepancy of climate and temperature, can use zeolite base rubber as the material of sealing ring for the slewing ring bearing, its reaction temperature range is much larger than that of butadiene-acrylonitrile rubber, and its highest reaction temperature can reach to 200 ℃. Regarding to sealing structure, there is special structure of sealing ring is shown as double-lip sealing for the wind turbine slewing ring, this sort of structure can avoid radiation and oxidation gases into the roller path, to guarantee quality of the roller path. In some special wind fields under some conditions, materials and structures of sealing ring of the slewing ring should be specially considered.

Deck crane slew bearing tests

A number of incidents have occurred recently involving failure of the slew bearings of ships’ cargo deck cranes, resulting in crane losses and serious injury to personnel.
These failures have been caused by undetected excessive wear in the slew bearings.

Rocking tests
Crane manufacturers generally recommend that ‘rocking tests’ are carried out every six months in accordance with their instructions, and that the results are recorded and monitored in order to ensure the wear tolerances remain within the limits permitted by the designers.

Cranes which are particularly at risk are those with single ball race slew bearings. Cranes fitted with this type of slew bearing must have rocking tests carried out, in accordance with manufacturer’s instructions, to determine that the amount of wear in the bearing races is within permitted limits.

Although cranes with single ball race slew bearings are considered to be most at risk, rocking tests on all deck cranes,where recommended by the crane manufacturer, must be carried out and the results must be recorded.

If no rocking test has been carried out in the previous six months, the crane in question will not be certified for further use.It will also be recommended that the crane is taken out of service and the Lifting Appliance Register will be endorsed accordingly.

Measuring proceadures for wear in slewing bearings for rope luffing cranes.The slewing bearing is an essential part of the crane and must be well maintained.
Over the years the slewing bearing will have some wear, and to be able to know if there is a need for changing the slewing bearing it is needed to keep a record of the wear.

The measurements should be taken reqularly, every 6 months.Measurements can be sent to the Maker for evaluation.

Note When measurements are to be taken the ship shall have as little list/trim as possible.


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