Abstract: The present invention provides a direct-drive electric machine such as a generator and a motor comprising a rotor or a mover and a stator. The direct-drive electric machine is configured with a plural-module combination structure in which the rotor or the mover and the stator are mutually combined such that a plurality of modules form one phase, respectively.

Abstract: The invention relates to an adaptive controlling method for controlling energy supplied by an electrical source to a resonance tank that is connectable to an electric load. The method comprises the step of determining an energy amount to be supplied to the tank, based on information of energy in the resonance tank.

Abstract: The invention relates to an adaptive controlling method for controlling energy supplied by an electrical source to a resonance tank that is connectable to an electric load. The method comprises the step of determining an energy amount to be supplied to the tank, based on information of energy in the resonance tank.

Abstract: The present invention provides a direct-drive electric machine such as a generator and a motor comprising a rotor or a mover and a stator. The direct-drive electric machine is configured with a plural-module combination structure in which the rotor or the mover and the stator are mutually combined such that a plurality of modules form one phase, respectively.

Abstract: The invention concerns a transverse flux electrical machine operating with alternating current, having a first element having an alternate arrangement of excitation cores and of flux return cores and a winding of electrical conductors, the winding of electrical conductors being wound as a toroid, inside all said excitation cores; a second element having an exciter section comprising two toothed magnetic structures, each toothed magnetic structure comprising a number of slots equal in number to the total number of excitation cores and of flux return cores, the corresponding slots of each magnetic structure being toothed by being aligned; a magnetized sub-assembly is inserted inside each indentation so that an alternating arrangement of magnetic north poles and south poles is produced in each of these magnetic toothed structures of said exciter section; an air gap between the first element and the second element; at least one of the first element and of the second element being capable of rotating around a rota

Abstract: An arc furnace which includes a shell with a hearth, a roof for the shell, the roof including a plurality of segments which are substantially electrically isolated from each other and from the shell, an electrode and a refractory section on the roof, and wherein the refractory section is at least partly electrically conductive.

Abstract: In the operation of a dc arc furnace components of the furnace are monitored to detect unwanted arcs. A first low impedance path is continuously established between the components. When an arc is detected a second conductive path of a predetermined impedance is established between the components, in parallel to the first low impedance path, to extinguish the arc. After the arc has been extinguished the second path is open circuited to restore the furnace to normal operation.

Abstract: A pulse generator is provided for energizing a coil with period bipolar current pulses for the purposes of airborne prospecting. The pulses have a generally square waveform, and the pulse generator includes a resonant DC to AC converter circuit including a DC input and an output coupled to the coil. A control circuit is provided for controlling the switching of the converter, and a resonant capacitor is connected in parallel across the DC input. A decoupling diode is provide for decoupling the resonant capacitor from the DC input when the voltage across the resonant capacitor exceeds that of the DC input. The converter includes first and second resonant charging sub-circuits, first and second resonant discharging sub-circuits, first and second freewheeling sub-circuits and first and second exponential charging sub-circuits.

Abstract: A power convertor has a partial series resonant convertor circuit for supplying power at a substantially constant level to a load of variable impedance, and a control circuit for controlling the operation of the convertor circuit. The control circuit includes sensing lines for sensing a variation in load impedance below a threshold value, and regulating means responsive to the sensing lines for reducing the power supplied to the load by lowering an input control signed to a voltage-controlled oscillator. The control circuit is arranged to operate the convertor circuit in a first normal load mode in which the impedance of the load is above the threshold value and a second reduced load mode in which the impedance of the load is below the threshold value so as to limit a rise in current through the load. The invention extends to a method of controlling a power convertor.