Abstract: A drive arrangement for a cycloidal marine propulsion unit including at least two electrical blade motors each associated to a respective blade for pivoting thereof, each blade motor being operationally coupled to a respective blade drive for actuating the corresponding blade motor. The at least two blade drives each include a respective blade drive power converter operationally coupled to a first common intermediate DC-link, wherein the at least two blade drives being configured to feed power from the first common intermediate DC-link to their respective blade motors, and to feed regenerative power from their respective blade motors to the first common intermediate DC-link. The disclosure also concerns a marine propulsion unit having such a drive arrangement, and a method of operating such a drive arrangement.

Abstract: A propulsion unit includes a housing supported on a vessel. A propeller shaft extends in the housing. The propeller shaft is rotatably supported with a first bearing and a second bearing. A propeller is attached to at least one end of the propeller shaft. The first bearing includes a first radial bearing and a first thrust bearing. The first radial bearing is a sliding bearing positioned axially inside the first thrust bearing. The first bearing is positioned at the first end of the housing and the second bearing being positioned at the second end of the housing or vice a versa.

Abstract: A switching device including a frame, a roll element, a control shaft, a drive system and a roll spring. The control shaft is adapted to control rotation of the roll element such that rotating the control shaft from an ON-position to an OFF-position carries out an opening event in which the roll element transfers from a first position to a second position. The drive system includes an actuator and an actuator spring. The drive system is adapted to rotate the roll element during the opening event to an intermediate position located between the first position and the second position. The roll spring is connected between the frame and the roll element, and is adapted to rotate the roll element to the second position during the opening event.

Abstract: The propulsion unit includes a frame construction having an upper portion forming a support arm protruding from a hull of the vessel and a lower portion forming a longitudinal compartment provided with a propeller shaft having at least one propeller attached thereto, and a first electric motor driving the propeller shaft. The method includes measuring vibrations of the propulsion unit with at least one measuring device, forming a first auxiliary torque control signal based on the measured vibration signal, adding the first auxiliary torque control signal to a first torque control signal produced by a first torque controller of the first electric motor. The first auxiliary torque signal acts against the measured vibrations.

Abstract: An electrical switch. The electrical switch comprises at least one fixed contact, a movable contact contacting the fixed contact, and at least one extinguishing apparatus positioned after the fixed contact in an opening direction of the movable contact. A permanent magnet is further positioned after the extinguishing apparatus in the opening direction of the movable contact.

Abstract: The arrangement includes at least one steering electric motor rotating the propulsion unit via a force transmission arrangement. The force transmission arrangement includes a differential including a first shaft connected to the steering electric motor, a second shaft connected to the propulsion unit, and a third shaft connected to a brake device. The third shaft is locked from rotation when a torque produced by an external force on the propulsion unit is below a threshold value, whereby power is distributed only from the steering electric motor to the propulsion unit or vice a versa. The third shaft is allowed to start rotating when the torque produced by the external force on the propulsion unit exceeds the threshold value, whereby power is distributed from the steering electric motor to the rotation of the propulsion unit and to the brake device or from the rotation of the propulsion unit to the steering electric motor and to the brake device.

Abstract: An electrical switch. The electrical switch includes at least one fixed contact and a movable contact contacting the fixed contact. At least one shutter element is arranged to move in synchronism with the movable contact. The shutter element is positioned in an extended position between the fixed contact and the movable contact and in a contracted position outside the patch of the movable contact allowing the movable contact to turn from the open position to the closed position.

Abstract: The arrangement comprises a seal (500) sealing a cylindrical rotating part (100) passing through an opening in a support structure in the vessel (10) against a medium (W). The seal (500) comprises a package of annular seal rings (510, 520, 530). Each seal ring (510, 520, 530) comprises a seal part (512, 522, 532) being supported in a corresponding seal support part (511, 521, 531). The seal support part (511) in the first seal ring (510) positioned closest to the medium (W) has the form of a cylinder (511A) provided with an annular flange (511B) at one end of the cylinder (511A). The outer surface of the cylinder (511A) is supported and sealed with an auxiliary seal (610) against the inner circumference of the opening. The annular flange (511B) is supported against the support structure (83) surrounding the opening.

Abstract: A support strut has an upper end rotatable supported at a bottom of a vessel and a lower end supporting a casing. A first electric motor within the casing drives a propeller via a first shaft. An annular nozzle surrounds an outer perimeter of the propeller and is fixedly supported on the casing, with a support construction comprising at least three vanes extending in the radial direction between the outer perimeter of the casing and the inner perimeter of the nozzle. A duct for water flow is formed through the interior of the annular nozzle. The propeller pulls the vessel in a driving direction. The vanes are positioned after the propeller in the driving direction of the vessel, whereby the vanes are optimized for redirecting rotational flow components of the flow produced by the propeller into axial thrust.

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: A rotary switch assembly, including a rotary contact and a stationary contact, and a rotary actuator for rotating the rotary contact such as to connect with and disconnect from the stationary contact. The rotary actuator includes a shield for shielding the rotary contact from a side that faces the stationary contact when the rotary contact and the stationary contacted are being disconnected from each other.

Abstract: A manual is disclosed for a frequency converter and a method, apparatus and a computer program product are disclosed for configuring a frequency converter. The manual can include a data storage storing operational configuration information of the frequency converter; wherein the configuration information is encoded to the data storage to be wirelessly readable from the data storage. The configuration information is obtained from the manual by wireless reading, and installed to the frequency converter by transmitting the obtained configuration information over a wireless connection.

Abstract: A method for operating a winch and a winch having a winch drum for spooling a spoolable medium, wherein the winch drum is rotatable about a first axis, a guiding member for guiding the spoolable medium, wherein the guiding member is movable along a second axis between two end positions, and an electric drive having a first electric motor for driving the guiding member towards one of the two end positions during spooling in or spooling out of the spoolable medium. The electric drive is configured to change the driving direction of the guiding member when a monitored torque of the first electric motor, or a quantity indicative thereof, exceeds a predetermined threshold.

Abstract: A method and apparatus are provided for balancing currents of two or more parallel-connected power semiconductor switches during an on-state of the switches. A control terminal of each switch is driven by a driver unit. The method includes determining ratios between the currents through the switches. For each switch, the method includes controlling the voltage at the control terminal on the basis of the ratios by controlling a level of a supply voltage of the driver unit of the switch, and after a turn-on commutation transient, modulating the output of the driver unit. The duty cycle of the modulation is controlled to minimize the time required for the transition of the voltage at the control terminal from the one voltage level to another.