Wind turbines convert the kinetic energy of the wind into mechanical power, and ultimately electricity. This electricity can be used immediately to power equipment, but is typically stored in batteries for future use. Larger turbines may generate enough power to carry or float larger loads (such as a small fridge during an overnight stay aboard), while smaller units produce enough electricity to power smaller loads for a few minutes (bilge pumps, etc.) or perhaps top off your battery banks after a weekend outing.
All generators share a few basic components: a rotor-they don’t propel, so they’re not propellers-with aerodynamic blades, an electrical generator, some form of rotor over-speed control, and a mounting system (pole, arch, etc.). Most also will have rotating electrical contacts, which enable the unit to operate in a continuous 360 degrees of rotation.
All but one of the units in our test, the KISS, had this feature. The KISS generator has an internal spring (inside the mount) and a rope lanyard tied to the tail of the unit and mounting pole-the lanyard is a specific length to prevent the unit from rotating more than three or so times, after which the spring is supposed to return it to its original position once the wind dies down.
Wind turbines either produce direct current (DC) or alternating current (AC) power, which is then converted to DC via a rectifier. Of the models we tested, the KISS and both Ampair units utilize a rectifier to convert AC to DC, while the Rutland 913, Air Breeze, and Superwind 350 produce DC. Each approach has its pros and cons: AC can be transmitted over longer wire runs with less power loss (due to overall resistance of system wiring), even when smaller gauge wire is utilized.
DC systems, on the other hand, don’t require the use of a rectifier, which reduces expense, cuts down on the number of parts that might fail, and eliminates a few installation steps. As for cons, DC motors have brushes and commutators, both of which require periodic maintenance to prevent generation of electromagnetic interference (EMI), which can disrupt onboard electronics. The rectifying diodes in AC-producing units can also be damaged if exposed to reverse-polarity voltages during installation or maintenance.
For more information on wind power generation, check out Marine Electrical Systems, Vol. 4: Alternative Energy.
Image Credit: Getty Images/gaspr13
