A motor comprising a main shaft, a first rotating member mounted on the main shaft, the first rotating member comprising a first arm extending radially outward from the main shaft, the first arm having a length L, a second arm extending radially outward from the main shaft, a first magnet mounted on the first arm such that a first pole faces a recess between the first and second arms, and a second magnet mounted on the second arm such that the first pole faces the recess between the first and second arms. The motor further comprising a piston movable towards and away from the main shaft in a generally radial direction and positioned proximate the first rotating member, the piston comprising a first magnet.