A few safety devices for the NG 12-5 include manual cut-off and over speed protection. The whole system is designed to German Standards VDE and DIN.
A recent announcement from Juhl Wind says it will be installing 33-kW turbines from Next Generation Power Systems Inc, Pipestone, Minn. Its fiberglass rotor blades are aerodynamically formed to the NACA 4424-4415 profile. But the big news with the recent NG 12-5 is that it has a device in the hub can vary blade pitch, an unusual feature for small wind-energy converters. Pitch control opens a door to other advantages, says Next Generation. For example:
- Automatic restarting after grid failure
- No shutdown in strong winds, and
- Constant frequency in stand-alone operation
The rotor drives a generator through three-stage spur gearing. A spring-loaded disc brake sits between the rotor and rotor bearing. Hydraulic controls are contained in a single block mounted on the generator housing. The rotor bearing and generator flange mount to the gearbox, which in turn connects to a wind tracker which is vane-driven by a worm gear.
The tower is an octagonal steel tube. The electronic safety and controls with instrumentation are housed in a switch cabinet on the tower pedestal. The cabinet also contains power terminals for connecting the turbine to the grid or consumer loads.
Next Generation says additional plusses for the NG 12-5 include:
- Automatic operation when grid connected
- Failsafe design is said to have been thoroughly field tested
- Easy to assemble
- Design lifetime over 20 year
Filed Under: Turbines
