The present invention provides several improvements in a slip ring (36) that is adapted to provide electrical contact between a rotor (42) and stator (40). In one aspect, a brush tube (39) is crimped around the upper marginal end portions of a plurality of individual fibers (38) inserted therein. In another aspect, a collimator tube (41) extends downwardly beyond the end of the brush tube to limit lateral movement of the fibers in the bundle when the rotor rotates. In yet another arrangement, a spring (55, 56) is arranged to bear against a current-carrying conductor to adjustably vary the force by which the lower ends of the fibers are urged to move toward the rotor.