Its high efficiency will be maintained down to very low power and at part load, he continues. This is a result of its construction with permanent magnet excitation -- an abrupt departure from the conventional approach which is to generate a magnetic field in the windings. Another feature that sets it apart from competing gearless machines now on the market is its modular construction. Both these innovations will push down costs, he says. "I think the machine has got a large number of features which would make it cheaper than other gearless machines, but that will only be fully resolved by producing a prototype."
The university is ready to move on to this next stage of the project. It is collaborating with Morley Electrical Company of Pudsey in West Yorkshire who would later expect to manufacture the machine. "We now anticipate seeing a prototype in operation over the next year or so," says Spooner.
He believes that gearless construction will prove to be an important feature for the next generation of larger machines. "As you move to higher powered turbines like the 1 MW size which seems more favoured nowadays, the gearbox becomes a predominant item in the machine. So there is a strong incentive for avoiding a gearbox altogether," he says. Spooner argues that a key to the future of wind in Britain lies in turbines that are quieter, cheaper to build and with improved efficiency so they will be cost-effective in low lying areas with lower wind speeds, where visual impact is of less concern than windy upland sites.