Abstract: An improved implantable pacemaker/defibrillator device in which a first and relatively simplistic technique is employed to detect an abnormal heart rhythm and a second more precise algorithm is utilized for the more difficult problem of confirming the arrythmia. Since the complex, higher power consuming device is utilized only for confirmation, overall power consumption is minimized. Optionally, the precise algorithm may be utilized periodically to adjust the sensitivity of the detection circuitry.

Abstract: A control system for a stand-alone electrical generator driven by a prime mover such as a wind turbine in which switches are operable in response to changes in the frequency of the generator output to change the load imposed on the generator by resistor means. The resistor means includes domestic resistive heaters and dump resistors, the switches for the former turning "on" at frequencies lower than those at which the latter turn "on". The frequencies at which the several switches in a given consumer's premises switch "on" are interlaced with the frequencies of the switches in other premises so as to avoid discrimination between consumers. The output frequency is thus kept relatively constant despite changes in wind speed.

Abstract: A mooring winch system in which automatic mooring duty is performed by a winch having an AC motor fed from the supply via a converter which includes a DC to AC inverter, the convertor producing a balanced three-phase square, quasi-square, sinusoidal or quasi-sinusoidal output. The motor thus can stall indefinitely, be driven in the sense of rope payout by tension force in the mooring rope, or run in the opposite sense to recover rope, without exceeding its rated temperature for that duty. Rope recovery is adequate both for normal duties and also where higher speeds of recovery are required and rope tension is maintained substantially constant throughout.

Abstract: An air pressurizing and purging system for electrical equipment contained in compartments with safety checks and interlocks ensuring inhibition of main power circuit completion until purging pressure and fan operation are verified by a timer for a set period.System failure initiates a trip after a delay to open the main power circuit.Re-energization of the main circuit requires full purge and verification procedure once more.

Abstract: Winding mechanism for example for cranes in which a winding drum is rotatable by two motors the first arranged to drive the drum so as to take up any slack rope when operating conditions, for example sea-state, reduce the load on the drum, the other motor driving the drum through an over-run device. If required the first motor is controllable in response to the difference between signals from the winding drum and a sensing drum in a manner to reduce the difference to zero to ensure motion of the winding drum in sympathy with motion of the messenger drum.