One of the small wind turbines selected for testing was Mariah Power's Windspire Giromill. The Windspire is a 1.2-kW vertical-axis wind turbine. The turbine tower is 9.1 meters tall, and its rotor area is 1.2 x 6.1 meters. The turbine has a permanent-magnet generator with a single-phase output at 120 volts AC.