Magnax technology is inherently scalable in diameter, with output torque quadrupling as the machine doubles in diameter.
But Magnax technology is also scalable in axial length by stacking multiple machines in parallel. The machine's torque (and power) is multiplied by connecting multiple identical machines, creating a multi-megawatt generator.
Magnax Axial Flux Direct Drive Generators are 40-70% lighter than traditional radial direct drive generators.
Reducing turbine mass is an ever-present aspiration for engineers, as it facilitates the ability to build taller wind turbines which are able to harness more powerful winds at greater heights.
By lowering generator mass, towers and foundations supporting nacelles will also be engineered using less steel, thereby saving on manufacturing costs.
In a Direct Drive wind turbine, the turbine hub is often mounted directly on the generator shaft.
With a traditional generator, all load forces on the shaft are carried by the stator housing. This will inevitably cause displacement of the stator, which will affect the radial air gap. This has an adverse effect on the generator's efficiency and durability, and can easily lead to catastrophic failure in the long run.
In the Magnax Machine, the load forces are carried by an independent bearing system, which can be perfectly fitted to the application.
And due to the axial air gap, even small deflections of the bearing system do not affect the air gap.
“We were astonished when we saw the specs of the Magnax 100-kw generator. It makes a huge difference when your generator weighs 850 kg instead of 4 tons! What’s more, it brings best-in-class efficiency and is comparable in price. ”
The efficiency and reliability of the drive train are key factors in the Cost Of Energy (CoE), produced by a wind turbine.
Magnax Direct Drive generators not only require much less maintenance than their geared counterparts, but they are also much less prone to failure.
Magnax machines also have much higher efficiencies at rated load, and the difference becomes even larger at partial load, where wind turbines operate most of the time.
|100-kW – 60 rpm generator/motor - 16.200 Nm Torque||Induction motor + Gearbox||Radial Flux Direct Drive||Magnax Direct Drive|
|Efficiency||80 – 88%||92 – 95%||96% - 97%|
|Axial length||1500 mm||700 – 1200 mm||140 mm|
|Weight||2000-3000 kg||2400 - 5000 kg||850 kg|
|Ease of installation||-||+||++|
|Maintenance cost||Very high||Low||Low|