Abstract: A motor with an integral magnetic torque limiting coupling which maintains the relative positions of the motor rotor and a coupling output shaft thereof when the rotor is rotated, and transmits up to a predetermined amount of torque during such rotation, which exceeds the maximum sustained torque which the motor develops during normal operation so as not to interfere with the torque transmission during normal operation of the motor while allowing the output shaft and rotor to slip relative to one another to prevent transmitting a torque above a maximum safe torque which may be safely applied to a gear train to be driven by the motor, thereby preventing damage to the gear train by the motor in the event of a sudden change of speed of the gear train.

Abstract: A connection socket for a submersible electric motor includes a connection box of the motor provided with two plates, one of which holds connection pins. The other plate is arranged to divide the connection box into two sealed rooms to prevent liquid coming into the box along the electrical cable from going further into the motor.

Abstract: Circuitry for generating tripping and blocking signals for the protection of electrical components included in electrical power supply networks as a result of the occurrence of faults therein provides multiphase pole tripping in the event that, after a single pole tripping has been executed, a new single phase fault occurs in any of the remaining phases of the electrical power supply network. Respective tripping and blocking signals are generated for each phase of the electrical power supply network in dependence on whether the fault lies ahead or behind the electrical component to be protected, respectively, in response to measurement of the voltae and current associated with transient waves generated by faults associated with each electrical power supply network phase.