Abstract: An arrangement for monitoring a condition of a direct current voltage circuit including first and second supply poles for forming an operating voltage. A first fuse is connected to the first supply pole, and has a supply pole and an output pole. A second fuse is connected to the second supply pole, and has a supply pole and an output pole. The arrangement can form one or several reference voltages (UREFa,UREFb,UREFc), can form a first measurement voltage (U1a,U1b,U1c,U1d) between the output pole of the first fuse and the supply pole of the second fuse, and can form a second measurement voltage (U1a,U1b,U1c,U1d) between the output pole of the second fuse and the supply pole of the first or the second fuse. One or several reference voltages and measurement voltages can be compared to estimate a condition of the first and second fuse, and a comparison result can be indicated.

Abstract: A system for the detection of welded contacts in a circuit of a line converter system has a plurality of inverter switches, a plurality of utility switches in which a pair of utility switches is connected in series through a line to a utility, a voltage detector, an electronic controller, and a DC input source. The line converter system converts incoming DC power into AC output power that is delivered to the utility grid. The voltage detector measures the voltage across a first node and a second node of the circuit and provides an output that is interpreted by an electronic controller for each step performed during a method of detection of welded contacts. The detection method has a sequence of test steps in which at least one switch is opened and/or closed, a DC bus of the inverter or the utility grid is used as a stimulus voltage, and the voltage is measured.

Abstract: A switching branch for a three-level rectifier and a method for controlling a switching branch for a three-level rectifier are provided. The switching branch includes a first diode and a second diode connected in series, a third diode and a fourth diode connected in series, a first controllable switch connected between a neutral DC output pole and a connection point between the first and the second diode, and a second controllable switch connected between the neutral DC output pole and a connection point between the third and the fourth diode. The switching branch controls the first controllable switch to be in a conductive state during a reverse blocking state of the first diode and the second diode, and controls the second controllable switch to be in a conductive state during a reverse blocking state of the third diode and the fourth diode.

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 simple and reliable anticipatory failure indicator is provided for fluid circulation piping, and a fluid cooling arrangement including such an indicator is provided. The indicator includes a first sacrificial member, which is designed to be in direct contact with the fluid within the piping and designed to be weaker than the piping. The indicator includes a chamber, which is isolated from the fluid circulation at least partly by means of the first sacrificial member. The indicator includes an electrical response member, which is arranged into the chamber and which is configured to produce an electrical response upon exposure to the fluid, which has entered to the chamber via a failed sacrificial member. Accordingly, the indicator is configured to provide an electrical response as a direct indication of a failed sacrificial member and as an anticipatory indication of failed piping.

Abstract: A method and arrangement of determining starting conditions of a solar converter in a photovoltaic system. The photovoltaic system includes a photovoltaic panel system having one or more photovoltaic panels. The method includes determining an open circuit voltage of the photovoltaic panel system, and determining beforehand limit values for the starting conditions, where the limit values include an open circuit voltage value and a temperature value, with which values the solar converter can be started. The method also includes determining beforehand the temperature dependency of the open circuit voltage of the panel system, determining a temperature of the panel system, and setting a criterion for starting the converter. The criterion includes determining, by using the determined temperature dependency and the determined limit values for the starting conditions, whether the determined temperature and the determined open circuit voltage enable the starting of the converter.

Abstract: An arrangement for steering and supplying propulsion power to a contra rotating propeller(s) (CRP) propulsion system in a marine vessel is disclosed. The arrangement can include a first propeller, a second propeller driven by an AC motor, and an AC generator. The AC motor and AC generator can have the same electrical frequency. Another electrical power source can be electrically connectable to the AC motor in parallel to the AC generator. A shaft of the second propeller is mounted rotatable in a support structure which is attached to a hull of the marine vessel, and a rudder is supported in a manner allowing pivotal movement of the rudder relative to the support structure.

Abstract: The present disclosure relates to a measuring bearing currents in an electrical machine. According to exemplary embodiments, radio frequency signals that are generated by electric discharges are detected by an antenna near the bearing. A synchronizing signal is combined with the origin of the bearing current and signal triggered by the synchronizing signal is measured.

Abstract: A converter circuit includes first and second input terminals, first and second capacitors, the second capacitor having a first terminal connected to the second input terminal and a second terminal forming a positive voltage node, first and third semiconductor components connected in series between the first input terminal and the positive voltage node, the midpoint between the series connection forming a first node, and a series connection of a first inductive component, a diode and a second inductive component. The series connection is connected between the second input terminal and the node. The diode's polarity allows current to pass from the direction of the second input terminal. A second node is formed between the first inductive component and the diode, and a third node is formed between the diode and the second inductive component. A third capacitor is connected between the first input terminal and the third node.

Abstract: An exemplary apparatus and method are provided in which the apparatus is provided with encoding configuration information as an optical code. The optical code is displayed on a display of the apparatus. The optical code can be read from the display and configuration information derived from the optical code is sent to a database of configured apparatuses.

Abstract: The present disclosure relates to sealing the propeller shaft of a ship using a sealing having a group of lip seals arranged consecutively in a direction of the propeller shaft so that a seal chamber is created between adjacent lip seals. The pressure of the first seal chamber on the propeller side can be close to the pressure of the surrounding water at the propeller shaft level, and the pressure of the second seal chamber furthest from the propeller can be adjusted to a fixed value that is lower than the pressure of the first seal chamber. The pressure of a third chamber located between the first chamber and the second chamber can be adjustable by pressure regulation devices to a value between the pressure values of the first and the second chambers by adjusting the pressure loss caused by the flow of a liquid medium.

Abstract: An arrangement for controlling frequency converter modules of an electric drive. In the arrangement, the frequency converter modules are arranged to control alternatively a first motor or several motors having less power than the first motor.

Abstract: A motor drive and a method in connection with a motor drive including a frequency converter are provided. The motor of the drive is connected to a load, and the motor is controlled with the frequency controller. The method includes the steps of converting changes in electrical quantities of the motor caused by actions affecting the load into observations representing the changes, selecting control symbols on the basis of matching of the sequences of observations with a set of valid patterns, and controlling the converter based on the selected symbols.

Abstract: An electronics compartment with a component space which is sealed off from a surrounding environment by walls, including an internal panel arranged in the component space along a wall of the electronics compartment for delimiting an internal channel between the wall and the internal panel. Air flowing in the internal channel can improve transfer of heat through the wall, and consequently, cools electric components in the component space.

Abstract: An electronics compartment is disclosed with a component space which is sealed off from a surrounding environment by walls. An internal panel is arranged in the component space along a wall of the electronics compartment for delimiting an internal channel between the wall and the internal panel. An external panel is arranged along a same wall of the electronics compartment as the internal panel, but outside the component space for delimiting an external channel between the wall and the external panel. Air flowing in the internal channel and external channel can improve heat transfer through the wall, and cool electric components in the component space.

Abstract: An arrangement is disclosed for supplying electric power to a propulsion system of a marine vessel having a propeller motor, which is connected to an AC generator. The AC generator supplies electric energy to the propeller motor. The AC generator is rotated by a rotating power unit. A frequency converter is electrically connectable in parallel to the AC generator and the frequency converter supplies electric power from a second power unit.

Abstract: A method includes selecting the branch of a ventilation system with the greatest pressure loss, opening a control valve in the selected branch and closing control valves in all other branches, controlling a fan to produce the desired air flow rate into the selected branch by using fan characteristic shaft power to air flow rate curves, and a shaft power estimate from the frequency converter and by adjusting the rotational speed of an electric motor to achieve the desired air flow rate, calculating the fan pressure corresponding to the desired air flow rate from fan characteristic fan pressure to air flow rate curves, saving the calculated fan pressure as a reference pressure, and adjusting the control valves in each of the remaining branches so that the desired air flow rate to each branch is delivered while the fan is controlled by the frequency converter to produce the reference pressure.

Abstract: An exemplary method and a control circuit are disclosed for controlling a power semiconductor component by producing a control signal (Ucin) for controlling the component, forming a second control signal (Ucout) in the potential of the controlled component from the control signal (Ucin), measuring a current flowing through the component, and comparing the measured current with a set limit. A fault signal (Ufault) having a logical state is provided on the basis of the comparison between the measured current and the set limit, producing a component control signal (Uave) from the fault signal (Ufault) and the second control signal (Ucout). If a fault is indicated, the component control signal has a value between high and low states, and otherwise the state of the component control signal (Uave) equals the state of the second control signal (Ucout).

Abstract: The disclosure relates to an electrical cabinet for receiving and enclosing an electrical apparatus such that the electrical apparatus can be isolated from surroundings by the electrical cabinet. To address water condensing inside the electrical cabinet, a roof construction of the electrical cabinet includes at least a first capillary part located above the electrical apparatus, and the first capillary part includes capillary grooves for recovering liquid condensing on the first capillary part.