The Antaris 2.5 small wind turbine benefits from Igus igubal self-aligning spherical bearings.
Only a few years ago small wind turbines were manufactured using simple mechanical design and control technology. Today this has evolved into increasingly high-tech products that compare well with larger systems. Currently small wind turbines are used mostly for supplying power to houses, geographical measuring stations or on boats or caravans. Experts predict a prosperous future for wind energy in electricity production in developing countries. The Antaris 2.5 small wind turbine is one such model with a promising future, profiting both technically and economically from Igus polymer plain bearings.
Heyde Windtechnik, located in Dippoldiswalde, Germany, was founded in 2001 and is dedicated, among other things, to the production of rotor blades and accessories for small wind turbines. In addition, the company markets the Antaris 2.5 as a complete system with a nominal output of 2.5kW. It is suitable for battery charging and can be used for wind heating as a supplement to solar heating, and to feed power into the home electricity system. It is claimed that, in good wind conditions, it is possible to almost halve the energy costs for a family home. In addition to this, there are many applications for small wind turbines in developing countries.
Company founder and Managing Director Michael Heyde, who designed the Antaris 2.5, says: "I wanted to develop a system that is robust, can withstand storms, is free from maintenance and, especially, is quiet. This is especially important near residential areas, where other systems could not fulfil all these conditions. Naturally it should also be able to withstand all climatic conditions – from Greenland to the Sahara – and work safely even in major storms like Kyrill, which hit Germany in 2006."
In order to achieve this safety in storms, a special mechanism was designed to tilt the entire generator upwards like a helicopter. This greatly reduces the surface area exposed to the wind and restricts output. The tip bearings of the rotor were selected from the Igus range of plain plastic bearings, and the unit also uses flange bearings from the igubal self-aligning range.
Designers can select from a complete range of igubal self-aligning bearings: rod ends, clevis joints, flange, spherical and pedestal plain bearings. Self-aligning bearings are easy to fit, adjust to any angular movement and can, in many cases, replace special housings. For standard plain bearings there is a spherical ball made of iglidur W300, a material that gives very low friction values in dry operation and has very low stick-slip, which is very important at low loads and for slow movements. The housing is made of igumid G, an impact-resistant polymer with long fibre reinforcement.
Igubal products work without problems even under difficult conditions and have excellent corrosion resistance, enabling them to be used in damp or wet environments. The igubal range can be used at temperatures ranging from -30 to +80degC and do not even need seals to protect against extreme dirt contamination – regardless of whether it is fine dust or coarse particles. The bearings are used technically dry and have very good vibration damping characteristics. The lightweight and compact bearings also save costs in two ways: they are inexpensive to purchase and need no maintenance. This final point was crucial for their use in the Antaris 2.5.
The secret to the success of Igus products in contrast to traditional bearings, which have a hard shell with a soft coating, is that all iglidur plain bearings consist of high-performance polymers, further improved through the use of precisely adjusted reinforcement materials and solid lubricants. The traditional approach using polymer-coated steel can fail due to the sliding layer migrating under heavy loads, edge pressure or vibration. The Igus plain bearings, made from iglidur, do not suffer from this, as the solid lubricants are mixed homogeneously throughout the wall thickness, therefore the lubricant cannot be pushed out of the way when the shaft starts to move.
Bearing material composition is also adjusted to each application, resulting in a range of customised materials. Igus engineers develop more than 100 polymer compounds every year, testing them in over 3500 trials, and have built up a comprehensive database of the tribological characteristics of the polymer over many years – knowledge that benefits customers in the long run. In order to find the right bearing for every application, users can access the igubal expert system. Here it is possible to select from various types of loads - radial/axial as well as static, cyclic, and dynamic. The expert system uses this data, together with other information, to calculate the bearing wear and the theoretical lifespan.
The positive characteristics of the igubal flange bearings made the decision easy for Michael Heyde to use polymer bearings: "There are mass-produced flange bearings made of metal, but these often need to be lubricated, because they corrode, or are too expensive for small wind turbines. I have not been able to find any comparable bearing to the maintenance-free, corrosion-resistant and economical igubal bearings that has the right mix of characteristics." In addition, they are easy to fit and are UV-resistant. According to Heyde, the Igus bearings ensure the tipping function operates correctly even in extreme storms with wind speeds in excess of 150km/h.
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