Abstract:
The propulsion unit comprises a strut having an upper portion with an upper end portion passing through a passage formed between a first outer bottom and a second inner bottom in a vessel. The upper end portion is rotatable supported with a slewing bearing and sealed with a slewing seal. An upper slewing seal prevents lubrication medium leakage from the slewing bearing, whereby access to the upper slewing seal is provided in a radial direction from the interior of the vessel or from the interior of the strut in order to be able to service the upper slewing seal. A lower slewing seal is positioned at a vertical distance below the upper slewing seal and prevents sea water from penetrating into the hull of the vessel, whereby access to the lower slewing seal is provided in a radial direction from the interior of the vessel or from the interior of the strut in order to be able to service the lower slewing seal.
Abstract:
Method and apparatus of splicing a paper web, in which a paper web from a new reel is spliced to a paper web from an emptying reel and a position of glue or two sided tape in the surface of the new paper reel is marked. The method includes receiving a command for splicing, determining the splicing time instant, accelerating a rotation of the new paper reel, detecting the glue or tape, controlling, based on the detected glue or tape, the rotation of the new paper reel in such a manner that the rotation speed of the new paper reel and the position of the glue or tape are as required at the splicing time instant, and splicing the paper web at the splicing time instant.
Abstract:
An exemplary method and arrangement for balancing currents of power semiconductors. The arrangement including multiple power semiconductor units and a central control unit. Each power semiconductor unit includes a power semiconductor and the central control unit and the power semiconductor units are arranged in a bi-directional ring, in which the central control unit sends control information for the power semiconductor units in both directions in the bi-directional ring and each power semiconductor unit receives the control information in both directions and forwards the received control information. Each power semiconductor unit configured to receive the control information from the first direction at a first time instant, receive the control information from the second direction at a second time instant, calculate a midpoint between the first and the second time instants, and control the power semiconductor component according to the control information after a time delay after the calculated midpoint has elapsed.
Abstract:
An electronic device including a sealed enclosure, the electronic components arranged inside the sealed enclosure and including high-loss high-temperature components, a main heat sink including ribs, wherein the high-loss high-temperature components are attached to the main heat sink and the ribs of the main heat sink are arranged outside the enclosure, a cavity formed inside the enclosure and divided into a plurality of channel-like sections, the channel-like sections configured for providing air flow guidance inside the enclosure and being interconnected at their ends, wherein at least one channel-like section contains the electronic components and at least one other channel-like section contains an air-to-air heat exchanger extending from inside the sealed enclosure to outside of the sealed enclosure, wherein the electronic components inside the at least one channel like section are adapted to be cooled by air flow inside the sealed enclosure.
Abstract:
An electrical system and method include a DC link, a controlled rectifier connected between the DC link and a power source, an energy storage, a DC to DC converter connected between the DC link and the energy storage, a motor, and a DC to AC converter connected between the DC link and the motor. The converters are configured to transfer power in both directions. The rectifier controls the DC voltage of the DC link when the DC link voltage is in a first voltage range. The DC to DC converter controls the DC voltage of the DC link by charging the energy storage when the DC link voltage is in a second voltage range, which has higher voltage values than the first voltage range, or by discharging the energy storage when the DC link voltage is in a third voltage range, which has lower voltages than the first voltage range.
Abstract:
A roll for rotating a movable contact of a rotary switch, and a method of mounting a switch are provided. The roll includes a first slot going along the diameter of the roll and open from the top of the roll for receiving the movable contact for contacting with a stationary contact of the rotary switch, and a second slot arranged perpendicular to the first slot for receiving teeth of an upper roll to be mounted together with the roll.
Abstract:
An arc quenching plate for an electric switch includes a first mounting portion and a second mounting portion for mounting the quenching plate to respective recesses of the switch. The first mounting portion and the second mounting portion have a different form when compared to each other.
Abstract:
A converter circuit with short-circuit protection can include a plurality of phase legs having a series connection of normally-on switches, between voltage rails of a DC voltage link, a DC link capacitor, and AC voltage connection points between the normally-on switches. A phase-to-phase short-circuit protection circuit includes a parallel connection of a resistive component and a controllable switch. The phase-to-phase short-circuit protection circuit including a first terminal connected to an AC voltage connection point and a second terminal forms an input or an output of the converter circuit; and a controllable switch is connected in series with the DC link capacitor. Upon lack of control of the normally-on switches the controllable switch of the at least one phase-to-phase short-circuit protection circuit and the controllable switch of the phase leg short-circuit protection circuit are adapted to be controlled to a non-conductive state.
Abstract:
A method and apparatus for optimizing energy efficiency of a pumping system includes at least one pump that controls a fluid level in a reservoir. The method includes a system identification stage and an energy efficiency optimization stage. The system identification stage includes determining pump characteristics for the pump, operating the pump with a range of flow rate conditions, determining a set of data points, and calculating energy efficiency optimization characteristics. The energy efficiency optimization stage includes determining a present static head value, choosing a value for a pump control parameter, and operating the pump on the pump control parameter.