Troublesome gearboxes are getting redesign attention on both sides of pond. Most news reported here comes from North American but in Europe, news on a solution comes from Multigear GmbH (www.multigear.de). The Germany-based gearbox manufacturer has redesigned a 1.5 MW gearbox, initially for GE turbines, with several features intended to hit close to the 20-year mark with a less maintenance than gearboxes get now. The company is confident enough in the strength and durability of the design to nickname it The Bull.

General manager Achim Oebel says that before the nickname came the ideas for beefing up a conventional design. “For instance, the first planetary stage will have five planet gears instead of the conventional three, to handle the huge torque that enters the unit. In addition, it uses Flexpins to hold the planet bearings,” he says. Flexpins allow a slight shift in the planet center line with load to improve load sharing on the gear teeth. “Furthermore, the design uses a second planetary stage and pressurized lubrication goes to all critical components such as bearings and gear mesh.”

U.S. partner Steve Elrod, General Manager of Blade Service Rotor Technic USA (www.bs-rotorusa.com), points out that all gears are removable in the nacelle and the gearbox will have 150 liters more oil than conventional gearboxes to reduce temperatures. Also, the roller bearings are case hardened and mounted with preload.

Oebel says a similar design has been working for about six years in a turbine in the Orkney Islands. Like north Texas, the Orkney Islands have been a favorite test spot in Europe because of its near constant high speed and gusty winds.

The first unit is being assembled now and after dynamometer testing, will go into service in a turbine for at least a year. When that completes, the company expects GL approval and scaled production with distribution in the U.S. WPE