Certification to IECEx, re-certification to ATEX21. May 2021
EW Hof at the SPS Connect trade fair15. November 2021
EW Hof delivers tailor-made generators for wind turbines
Electricity from wind power plays a significant role in reaching global climate goals. Network-independent systems are particularly suitable for supplying remote research stations, individual settlements or farming operations. EW Hof builds generators that can be used by off-grid wind turbines to generate electricity for consumers, even under trying conditions.
Innovative solutions for future power generation
A growing part of the general power supply comes from wind energy. Efficient systems on land can generate between 1.5 and 4 megawatts, offshore as much as 9 MW. Factories, cities and infrastructure are the grateful consumers of electric power fed into the grid from wind. However, in some locations it is either extremely costly or even impossible to connect with the grid. A remote research station, an isolated village or an independent settlement can, if suitably located, supply itself with wind energy. Small wind turbines without grid access, so-called off-grid systems, serve as electricity generators. Single turbines of this kind can generate 110 kilowatts.
EW Hof is already known as a provider of pitch motors. Pitch motors regulate the performance of wind farms by setting the angle of the rotor blades to ensure the entire system makes the best use of the prevailing wind conditions. We became involved in wind generators for electricity production a few years ago. Most recently, one of our generators was launched at the end of 2020 in Belgium in a tilt-up tower. Since then, it has been reliably converting wind energy into electricity. This example is also an advanced model, built and customised according to the individual requirements of our customer. Three of EW Hof’s generator designs have been used in small turbines since 2015 and 2016. In the next two years, another 14 of our generators will go into operation.
Challenging design seamlessly solved
Generators for wind turbines can be integrated into the powertrain in two different ways:
- As classic drive with transmission between the rotor hub and the generator
- As direct drive (without transmission) where the generator rpm corresponds to the rotor rpm.
Our tailored generators for small wind turbines in isolated operations solve the special challenges in electric design and mechanical design. On the one hand, the generator must reach optimum efficiency at a very low speed of 60 rpm. On the other hand, the generator must be physically resilient in a few aspects: It must be able to absorb vibration and shaking without being protected or cushioned by an intermediate transmission. EW Hof has built a multi-pole permanently excited synchronous generator especially for meeting these requirements. Its axle height from the base supporting surface up to the shaft centre is 650 mm, its diameter 1,300 mm. Unlike their huge cousins, climbing small wind turbines from the inside is not possible. Therefore the rotors and generators need to support other types of maintenance. For this reason, non-slip rubber surfaces are built onto the generator to allow access without slipping.
Competent manufacture and correct installation
Due to our own in-house manufacturing at EW Hof, we can produce quickly and flexibly, as soon as the design is ready.
Speedy implementation of demanding projects
In developing our projects, we place great value on the cooperation with our customers. As a provider of special electric machines, with every piece we manufacture, fulfilling the specific, individual requirements of the respective customer is what it is all about. Our customers often come to us with a request to implement projects particularly quickly.
At the end of August 2020, a small wind turbine builder approached us whose turbines have been using generators from EW Hof – and indeed “without any disturbances and problems“ for three or four years. A similar, advanced generator had to be launched in the calendar year 2020. A tight deadline of just four months! Together with our customer’s technicians, we cleared up the remaining technical questions. At the end of November, the required generator was ready for delivery and at the end of December, it was generating its first kilowatt hours. Its “brothers and sisters” will be along soon. With a delivery time of 12 weeks, the next generation of generators is also ready for the construction of further generation systems in isolated operations, quick and on time. Which electric motors and/or generators do you require? EW Hof is your experienced partner for special electric machines with in-house development, design and manufacture.