MS PMGs represent a very compact, slower speed solution offering the highest efficiency with low maintenance needs. ABB produced the world´s first MS PMG Multibrid-type design in 2000: this has the turbine main bearing and PM generator integrated with a single-stage gearbox.
NEW SEMI-INTEGRATED MS PMG FOR OFFSHORE TURBINES
Medium speed designs:
- Compact size with low turbine top-head mass
- For multi-MW powers up to 7 MW and more
- Highest efficiency levels (over 98 %) at all turbine speeds
- Cost-efficient with low magnet mass
Nominal speed can be selected between 100 - 500 rpm using a 1- or 2 stage gearbox.
There are three potential ways to implement a medium speed design.
The pitch tube for cable passage and the brake disk need to be considered in all designs.
- Gearbox and generator share same frame, bearings and shaft.
- Requires joint development project involving gearbox and generator manufacturers
- Scope of supply can range from stator and rotor parts only to full generator.
- Generator is integrated with gearbox via supporting flange.
- Only mounting interface flange and coupling need to be agreed.
- Cooling can be optimized, with more options available.
- Generator is separate unit mounted independent of gearbox.
- Similar construction to high speed generator with 3-stage gear.
- Standard generator platform, reliable, cost-efficient, with fast delivery