The present article, briefly, describes the theoretical design procedure of Wells turbines, typically utilized in Pneumatic Wave Energy Conversion Systems (PWECS). The principle behind the PWECS consists of extracting the pneumatic energy caused by an oscillating water column by the entrance of water waves in enclosed spaces. The paper establishes the design and experimental testing of a small permanent magnet generator suited for the wells turbine under development. The adequate matching between the Wells turbine and the generator has been conceived as a portable 50w d.c. electricity generation device; to be used, either, to powering telecommunications systems in military operations or to power navigation aids in rivers or at sea.