Power swivel for transmitting electrical power from a first terminal to a second terminal, includes a central part with a hub and an outer ring of a magnetic material, coaxial with and surrounding the hub, the outer ring and central part being rotatable relative to one another around a vertical axis, at least two radial arms of a magnetic material projecting from the hub or from the outer ring, adjacent arms being spaced-apart, each arm carrying a conductor wound around the arm to form a coil for generating a magnetic flux along a radial flux path through the arm, the conductors being connected to the first terminal, wherein the outer ring or the hub has a cylindrical surface at close proximity to free ends of the arms, a plurality of axially extending conductors being distributed along the circumference of the outer ring or hub at or near the cylindrical surface.