Abstract: A bridge leg switching a DC voltage to produce an AC voltage at its output terminal for supply to an inductive load. The bridge leg has first, second, third, and fourth switch assemblies, and at least a first inductive element. The first and second switch assemblies are serially connected between the bridge leg input terminals, the bridge leg output being formed at a point of interconnection of the first and second switch assemblies. The third and fourth switch assemblies are serially connected between the bridge leg input terminals, the inductive element being connected between a point of interconnection of the third and fourth switch assemblies and the bridge leg output. The third and fourth switch assemblies are controlled such that reverse current through either of the first or second switch assembly is reduced compared to bridge leg output current prior to the moment the bridge leg output is switched.

Abstract: A bridge leg switching a DC voltage to produce an AC voltage at its output terminal for supply to an inductive load. The bridge leg has first, second, third, and fourth switch assemblies, and at least a first inductive element. The first and second switch assemblies are serially connected between the bridge leg input terminals, the bridge leg output being formed at a point of interconnection of the first and second switch assemblies. The third and fourth switch assemblies are serially connected between the bridge leg input terminals, the inductive element being connected between a point of interconnection of the third and fourth switch assemblies and the bridge leg output. The third and fourth switch assemblies are controlled such that reverse current through either of the first or second switch assembly is reduced compared to bridge leg output current prior to the moment the bridge leg output is switched.

Abstract: The present invention relates to a switched power converter including a base plate on which at least one heat sink is arranged. The converter further includes at least one power transistor arranged on a side of the at least one heat sink. Further, at least one spring element is arranged to press against the power transistor arranged on a side of the at least one heat sink and an oppositely facing side of either an adjacent heat sink or a base plate end face parallel to the at least one heat sink.

Abstract: The present invention relates to a switched power converter comprising a base plate on which at least one heat sink is arranged. The converter further comprises at least one power transistor arranged on a side of the at least one heat sink. Further, at least one spring element is arranged to press against the power transistor arranged on a side of the at least one heat sink and an oppositely facing side of either an adjacent heat sink or a base plate end face parallel to the at least one heat sink. This is highly advantageous in that a force is applied to the power transistor by the spring element. This will press the power transistor against the heat sink on whose side the transistor is arranged. Thermal contact is thus established between the power transistor and the heat sink, and heat dissipation from the transistor via the heat sink is greatly facilitated. Further, the spring elements are a cost-effective way of attaining a high compressive force on the power transistors.

Abstract: It is presented a gate driver circuit for driving an electric switch, the switch being arranged to control a main current using a gate signal. The gate driver circuit comprises: a non-linear capacitor means having a lower capacitance when an applied voltage is under a threshold voltage and a higher capacitance when an applied voltage is over the threshold voltage, wherein the non-linear capacitor is arranged to be connected between a high voltage connection point of the switch and a connection point for the gate signal; a current change rate sensor, the current change rate sensor being configured to detect changes in a main current of the electric switch and to control a gate signal of the electric switch depending on the current change; a gate buffer; and at least one current source, arranged to drive the gate buffer. The current change rate sensor is connected to control the current source to thereby control the gate signal of the electric switch.

Abstract: It is presented a gate driver circuit for driving an electric switch, the switch being arranged to control a main current using a gate signal. The gate driver circuit comprises: a non-linear capacitor means having a lower capacitance when an applied voltage is under a threshold voltage and a higher capacitance when an applied voltage is over the threshold voltage, wherein the non-linear capacitor is arranged to be connected between a high voltage connection point of the switch and a connection point for the gate signal; a current change rate sensor, the current change rate sensor being configured to detect changes in a main current of the electric switch and to control a gate signal of the electric switch depending on the current change; a gate buffer; and at least one current source, arranged to drive the gate buffer. The current change rate sensor is connected to control the current source to thereby control the gate signal of the electric switch.

Abstract: The present invention relates to an electrical drive unit comprising a circuit board, a plurality of components, attached to a first side of the circuit board, a heat sink, arranged on the first side of the circuit board, a positioning assembly, arranged on a second side of the circuit board opposite the first side of the circuit board. The circuit board comprises a plurality of holes between the first and second sides, where through the positioning assembly has a plurality of protrusions arranged against the plurality of components, such that each component of the plurality of components individually is pressed against the heat sink by the positioning assembly.

Abstract: An inverter type drive unit for feeding AC electric power of variable parameters to an electric motor has an electronic control section, and a power converting and output section which includes one or more identical power modules, each forming a complete 3-phase output stage. The power modules are arranged side-by-side in a multiplying direction and are clamped by retaining devices to a cooling structure. The power modules are connected in parallel to DC input terminals and to AC output terminals via conductive sheets which are insulated from each other. The DC connected conductive sheets cover substantially the entire physical surface area covered by the power modules so as to accomplish an even, simultaneous and low impedance DC current supply to all power modules.

Abstract: The present invention relates to a susceptor (3) for epitaxial reactors, comprising a body (31) provided typically with at least one recess (311) for housing substrates on which epitaxial growth is performed; the susceptor (3) comprises a projecting part (32) able to be gripped by a tool (9) so as to be introduced into and extracted from a reaction chamber (12) of an epitaxial reactor.

Abstract: This invention propose a way of controlling the flux density in a current transformer to keep the transformer core saturated between two consecutive measurements in a sampling measurement system. Saturation disables transformation of primary to secondary current, and thereby disables losses in the secondary circuit during this time. Both AC and DC currents are possible to measure. The use of saturation of the transformer core also permits the core to be designed physically very small. In order to get effective and accurate low power consuming measurements, both the magnetic fields originating from primary current flowing in the primary winding and external magnetic fields must be symmetrically physically spread in the transformer core. This greatly limits the possible physical arrangement of the primary winding.

Abstract: A power terminal for electrical connection of an electric cable to a circuit board comprises a main body (8a) having a central longitudinal axis and means (12, 12a) for attaching a cable to the main body. An eccentric body (8b) integral with the main body (8a) and having a through hole (13) is arranged to receive a screw. A space (20) is provided at the bottom of the power terminal adjacent to the eccentric body. This configuration provides a means for securing the terminal in an easy and efficient way while also providing for mounting of a current measuring device, for example.

Abstract: This invention propose a way of controlling the flux density in a current transformer to keep the transformer core saturated between two consecutive measurements in a sampling measurement system. Saturation disables transformation of primary to secondary current, and thereby disables losses in the secondary circuit during this time. Both AC and DC currents are possible to measure. The use of saturation of the transformer core also permits the core to be designed physically very small. In order to get effective and accurate low power consuming measurements, both the magnetic fields originating from primary current flowing in the primary winding and external magnetic fields must be symmetrically physically spread in the transformer core. This greatly limits the possible physical arrangement of the primary winding.

Abstract: A blowbox for use in a plant for drying a material web includes an essentially horizontal box wall having formed therein circular orifices and eyelid perforations each of which includes a slit extending in parallel with the center line of the upper box wall. A depression is formed m the upper box wall adjacent one side of the slit. The eyelid perforations are arranged in two rows and parallel with the center line and together they form a zigzag pattern about the center line that intersects the depressions of the eyelid perforations in both rows. The orifices are disposed in a first and second pair of rows with both rows in each pair positioned on either side of and spaced equally from the center line. The upper box wall has a shallow continuous arcuate shape across its entire width.

Abstract: A control circuit arrangement for an electric motor drive unit includes a circuit board (10), a heat conductive substrate (12) carrying power semiconductors (13), a heat absorbing mounting structure (14) disposed in heat transferring contact with the heat conductive substrate (12), and a clamping structure (20) for clamping the circuit board (10) and the heat conductive substrate (12) to the mounting structure (14). A number of electrically conductive distance or spacer tube elements (22) are disposed between the circuit board (10) and the heat conductive substrate (12) for distributing the clamping force of the clamping structure (20) from the circuit board (10) to the heat conductive substrate (12) while forming electrically conductive leads between the circuit board (10) and the heat conductive substrate (12).

Abstract: The invention relates to an arrangement in cylinder drying, intended for incorporation in a paper machine and including a plurality of heated cylinders (1) arranged substantially parallel in two rows, about which the paper web (2) is taken serpentine during drying, whereat it is carried by an endless porous fourdrinier wire (3) which presses the web against the cylinder surfaces in one row of cylinders and lies between the paper web and the cylinders in the other row. For preventing the web from lifting from the wire as a result of pressure differences on either side thereof, there are blowing boxes (11,12) arranged for blowing out air in at least some of the pockets (4,5) situated on opposite sides of the web, each of said pockets being formed by the web and three cylinders lying consecutively in the travelling direction of the web.

Abstract: The invention relates to a plant for drying a material web. Such plant includes a plurality of upper (3) and lower blow boxes arranged substantially mutually parallel and at right angles to the travelling direction of the web. The lower boxes are intended to support the web and are provided in their surfaces facing towards the web with orifices for blowing air in directions substantially parallel to the plane of the web. The air ejection velocity is thereby sufficient to maintain the web in a specified floating position above said boxes. The upper blow boxes (3) are situated on the other side of the material web and have orifices for blowing air substantially perpendicularly to the plane of the web. According to the invention, the distance (H) between the blowing orifices of the upper blow boxes and the web is variable. It is furthermore adjustable so that the relative energy requirement for the upper blow boxes may be brought closely into the region of the value 1.

Abstract: The invention relates to an arrangement for pulling the tail of a web-like material through a drying or cooling plant. In such a plant the web-like material is floated on air at a given distance from a surface provided with air delivery orifices. The web-like material (10) is thereby caused to pass zig-zag over drivable reversing rolls (2), while an endless traction or pulling member (3) in the form of a belt or rope runs in a separate path through the plant, substantially parallel to the material web, and is provided with means (12,13,14,15) with the aid of which the forward web end or tail (11) is attachable for pulling through the plant. At least one of the reversing rolls (2) is adapted at one end portion for carrying the tail pulling member either directly or over a pulley (9) drivably connected to said end portion. Driving the tail traction member is performed with the same means as drive the reversing rolls.

Abstract: Web material is carried on air to advance the material in a fixed stable floating position through one or more decks of a treating plant, preferably a drier. The air is supplied through pairs of apertures arranged in the upper surface of blow-boxes distributed in the conveying path of the material which apertures eject the air in pairs of streams facing away from each other. To reduce deflection of the material between said pair of apertures the space between said apertures is supplied separately with a great volume of secondary air of the same static pressure as that prevailing on the upper surface of the material, which secondary air is taken along by ejector effect by the primary air streams ejected from the apertures of the blow-boxes.

Abstract: A treatment plant for web material which, when bent, exhibits stiffness transverse to the direction of bending. The treatment plant comprises a series of blow boxes arranged in sections with the boxes in each section having parallel plane perforated surfaces on opposite sides of the web path. The perforations are graduated in degree with a high degree of perforation on one side of the web path being opposed by a low degree of perforation on the other side of the web path, and vice versa, so that the web assumes a wave shape between the first and second planes, the wave staying with its nodes in definite positions closer to the one plane opposite the highly perforated group in the second plane and closer to the second plane opposite the highly perforated group in the one plane.

Abstract: A heating system for a room comprising two heat pumps. A base heat pump is designed so that its evaporator never freezes up or that no frost layer forms during wintertime operation. An auxiliary heat pump is provided and is put into operation during times of extreme cold, whenever the capacity of the base heat pump is not enough to sufficiently heat the room. When the outside heat exchanger of the auxiliary heat pump freezes up, provision is made to reverse the operation of the auxiliary heat pump so the outside heat exchanger becomes the condenser. Thus, the outside heat exchanger is thawed.