Abstract: A current-limiting dropout fuseholder includes multiple current paths through the fuse body. A primary current path includes a high current fusible element. A secondary current path in parallel with the primary path includes a triggering conductor that extends outside the fuse body and is connected to a moveable support. The second current path further includes a first spark gap for severing the triggering conductor upon the occurrence of a fault and the shifting of the fault current from the primary current path to the second current path. A second spark gap formed between the primary and the second current paths ensures that the fault current flows across the first spark gap for a time sufficient to sever the triggering conductor, thereby ensuring that dropout will occur.

Abstract: An apparatus for detecting and properly orienting a hydraulically-actuatable tool in a borehole and commencing drilling in a single trip of the drill string includes an MWD subassembly, for sensing the orientation, and a bypass valve for setting the hydraulically-actuatable tool once it is properly oriented and for thereafter conducting the drilling fluid to the cutter assembly. The method of setting a hydraulically-actuatable tool and commencing drilling in a single trip of the drill string includes the steps of running the hydraulically-actuatable tool into the borehole on a drill string which includes an MWD subassembly, sensing the orientation using the MWD subassembly, orienting the drill string to the desired orientation, and setting the hydraulically-actuatable tool.

Abstract: A current responsive latching apparatus may be employed in a dropout fuseholder or other electrical component for retaining the component in a current-carrying position and disconnecting and isolating the electrical component upon the occurrence of an overcurrent of a predetermined magnitude. The apparatus includes a current path through the component, including a current-carrying stud or conductor, a portion of which extends outside the component for releasably engaging a support member. A latching apparatus, which may include an actuating member of memory allow or a bimetallic material, engages the conductor to retain the support member in a supporting position beneath the electrical component. The apparatus may further include a heater element in the current path to ensure that the actuation member is heated to the temperature necessary to cause it to change shape and release the conductor upon the presence of an overcurrent.

Abstract: The control valve includes a spring refiner which is threadly retained in the valve body and which may be adjusted so as to incrementally vary the hydraulic pressure required to open the valve. The valve additionally includes stops or limits so as to prevent the spring retainer from being grossly misadjusted which, when used in the hydraulic control system of the recloser, may cause undesirable miscoordination with the operation of other circuit breakers and protective devices. The valve additionally includes a self-locking mechanism to prevent the valve from falling out of adjustment due to vibration or improper handling.