Patent ID: 8362634

Claim:
A modular power source configured for use in a rotating apparatus such as an underground boring head of a drill string in order to provide electrical power to another component in the rotating apparatus, the modular power source comprising an outer housing including a cover tube, a first conductor cap coupled to a first end of the cover tube, and a second conductor cap coupled to an opposite second end of the cover tube, wherein the cover tube, the first conductor cap, and second conductor cap cooperate to define a module space therebetween, a control module positioned to lie within the module space near the second conductor cap, the control module including a control system and an energy storage unit, wherein the energy storage unit is electrically coupled to the control system and the control system is electrically coupled to both the first and second conductor caps, a generator module positioned to lie within the module space between the first conductor cap and the control module, the generator module including a gravity-positioned stator and a relative rotor coupled to the gravity-positioned stator for rotation about a central axis, wherein the gravity-positioned stator and the relative rotor are configured to rotate relative to each other, and a weight included in the gravity-positioned stator to move therewith, the weight being positioned in the module space, wherein the weight includes a center of gravity offset from the central axis.