Lightweight return flux alternator

In one embodiment, a return flux linear alternator employs a magnet assembly that includes a pair of permanent ring magnets with opposing polarity and a pair of air gaps. The additional permanent ring and air gap complete a magnetic flux loop of the alternator rather than the magnet pole, as in traditional designs. An alternator coil assembly includes a pair of oppositely wound coil sections that each linearly move through a respective one of the pair of air gaps. In addition, the return flux linear alternator may employ a variety of structures to increase mechanical strength, including a reinforcement fabric, and a variety of structures to increase electrical efficiency, including a thermally conductive but electrically nonconductive spacer between the coil sections and multiple pairs of electrical leads.