Abstract: The time synchronization of a network is protected against unauthorized changes to the grandmaster clock of a base time domain by monitoring the physical communication interfaces of a network device for arrival of messages relating to time synchronization. If the messages relating to time synchronization apply to the initially set-up and synchronized base time domain, a check is performed to determine whether the messages relating to time synchronization announce a new grandmaster clock having better clock parameters than those of the present grandmaster clock. If so, a virtual base time domain is started by the network device. If the verification reveals that the proposed new grandmaster clock is trustworthy or valid, the network device discontinues the virtual time domain, updates its stored information concerning the grandmaster clock and, from this time onward, sends messages relating to time synchronization that are based on the new clock parameters to the network.

Abstract: Methods and systems for generating pulses in drilling fluid are described. The methods include driving rotation of a rotor relative to a stator of a pulser assembly in an oscillatory manner. The oscillatory manner includes rotating an obstructing element from a middle position to a first blocking angle position and rotating the obstructing element from the first blocking angle position to a second blocking angle position such that selective obstruction occurs. Rotation of the at least one obstructing element selectively obstructs a stator flow passage when drilling fluid is flowing through the drill string to generate a pressure pulse in the drilling fluid and the oscillatory manner is an oscillation of the obstructing element between the first blocking angle position and the second blocking angle position such that a single oscillation is between two obstructed states of the stator flow passage.

Abstract: A drilling system includes a magnetic coupling and an oscillation absorber. The magnetic coupling has a rotor that rotates about an axis of rotation. The oscillation absorber is in operable communication with the magnetic coupling and includes an outer layer coupled to a separator layer of the magnetic coupling to form an enclosed area. An absorber shaft of the oscillation absorber is at least partially within the enclosed area and is coupled to the rotor. The absorber further includes an outer mover arranged such that rotation of the absorber shaft causes the outer mover to rotate due to interaction of inner absorber shaft magnets and outer mover magnets.

Abstract: A drilling system includes a magnetic coupling and an oscillation absorber. The magnetic coupling has a rotor that rotates about an axis of rotation. The oscillation absorber is in operable communication with the magnetic coupling and includes an outer layer coupled to a separator layer of the magnetic coupling to form an enclosed area. An absorber shaft of the oscillation absorber is at least partially within the enclosed area and is coupled to the rotor. The absorber further includes an outer mover arranged such that rotation of the absorber shaft causes the outer mover to rotate due to interaction of inner absorber shaft magnets and outer mover magnets.

Abstract: A drilling system includes a magnetic coupling and an oscillation absorber. The magnetic coupling has a rotor that rotates about an axis of rotation. The oscillation absorber is in operable communication with the magnetic coupling and includes an outer layer coupled to a separator layer of the magnetic coupling to form an enclosed area. An absorber shaft of the oscillation absorber is at least partially within the enclosed area and is coupled to the rotor. The absorber further includes an outer mover arranged such that rotation of the absorber shaft causes the outer mover to rotate due to interaction of inner absorber shaft magnets and outer mover magnets.

Abstract: A drilling system includes a magnetic coupling and an oscillation absorber. The magnetic coupling has a rotor that rotates about an axis of rotation. The oscillation absorber is in operable communication with the magnetic coupling and includes an outer layer coupled to a separator layer of the magnetic coupling to form an enclosed area. An absorber shaft of the oscillation absorber is at least partially within the enclosed area and is coupled to the rotor. The absorber further includes an outer mover arranged such that rotation of the absorber shaft causes the outer mover to rotate due to interaction of inner absorber shaft magnets and outer mover magnets.

Abstract: An alternator an electronic voltage pre-regulation circuit adapted for incorporation into a drill string is provided and includes: a plurality of n-phase generators for providing alternating current (AC), wherein the AC of each generator is rectified to a direct current (DC) voltage using a respective rectifier to provide a DC power supply, and each DC power supply is arranged in series for being one of connected and disconnected from an output of the alternator. A method and a drill string are provided.