Abstract: The invention pertains generally to manufacturing and installing a semi-membrane tank for liquefied natural gas (LNG). Specifically, the invention relates to a method and apparatus for facilitating off-hull manufacturing of a completed semi-membrane LNG tank and installation of the tank in a permanent supporting structure, such as a ship's hull. Embodiments of the invention include attaching a support structure to the top and the sides of an LNG tank and attaching a support net to the support structure. The support net may be configured to support the bottom of the tank including any insulation that may be applied to the bottom. Once the support structure and support net are attached to the tank, the tank may then be moved from an assembly location to a permanent support structure where it may be permanently attached.

Abstract: In the support arrangements for a semi-membrane tank walls described in the specification, the top and side walls of a semi-membrane tank are provided with stiffener members and a surrounding tank support structure has support members which are connected to the stiffener members through support assemblies which provide vertical support for the tank walls while permitting relative motion in the horizontal direction. Each support assembly includes a bracket affixed to one of the support members and a spool affixed to a wall stiffener along with a thermally insulating block having an end portion slidably received in the bracket and having an internal groove extending in a direction orthogonal to the sliding motion of the end portion. The enlarged head of the spool affixed to the stiffener is received in the groove, thereby permitting relative motion of the tank wall with respect to the support structure and two orthogonal directions while providing load support for the tank wall in the vertical direction.

Abstract: In the embodiments described in the specification, an electric motor has a stator and a rotor and a wrap layer includes composite lamina arrangement containing a liquid barrier with a veil cloth and a chopped strand mat resin layer, a strength element containing a hoop wrap including a polymeric resin layer with continuous fibers extending circumferentially around the rotor and another polymeric resin layer with fibers extending helically, a liquid barrier having a veil cloth and a chopped strand mat resin layer and another strength element including a polymeric resin layer with continuous fibers extending circumferentially around the rotor. The outer surface of the composite lamina arrangement may be corrugated to promote or inhibit flow of liquid through the space between the stator and the rotor.

Abstract: In the embodiments described in the specification, an impeller is manufactured by providing a mold for one angular segment containing one vane of an impeller and corresponding hub and rim portions, injection-molding fiber-reinforced polymer composite resin material into the mold to produce a plurality of substantially identical segments, and assembling the segments into an impeller by bonding corresponding mating end surfaces of the hub and rim portions of the segments. A veil cloth is applied to the outer surface of the rim portion and impregnated with resin material to complete the impeller structure.

Abstract: Encapsulation of a permanent magnet rotor is achieved by applying a glass roving material to spaces in the rotor structure, applying a veil cloth around the outer surface of the rotor, mounting a vacuum bag with vacuum ports around the outer surface of the rotor, removing vent plugs from the end walls of the rotor and screws from an inner ring of the rotor and replacing them with vacuum ports and applying a vacuum to the vacuum ports. After air has been removed from the rotor, an encapsulating resin is applied to some of the ports to introduce resin into the interior of the rotor. After curing of the resin the vacuum bag is removed and the outer surface of the rotor is machined to the desired outer dimension of the rotor.

Abstract: In the embodiments described in the specification, a rim-driven propulsion pod arrangement has a cylindrical housing with a duct providing a flow path for water and a rotor assembly supported from a central shaft and containing a rotating blade row and driven by a rim drive permanent magnet motor recessed in the housing. An array of vanes downstream from the rotating blade row is arranged to straighten the flow of water emerging from the rotating blade row. Radial bearing members on the rotor have a hardness less than that of the shaft on which the rotor is supported and relatively soft protrusions are provided in the space between the rotor and the housing to limit excursion of the rotor. A thrust bearing has wedges arranged to form a water wedge between facing surfaces of the rotor and the rotor support during rotation of the rotor.

Abstract: In the embodiments described in the specification, a permanent magnet machine includes a stator having windings which intercept flux received from peripheral pole pieces in a rotor generated by permanent magnets disposed between the pole pieces. In order to control the flux passing through the stator windings, flux shunts are provided between the pole pieces and a winding on the core of each flux shunt generates flux in the shunt in proportion to current supplied to the winding so as to decrease the flux from the magnets which can be diverted from the pole pieces through the shunt. Current is supplied to the flux shunt windings in accordance with the instantaneous difference between the wave shape of the output from the machine and a desired wave shape stored in a control unit. An encoder supplies a signal to the control unit indicating the instantaneous position of the rotor with respect to the stator.

Abstract: In the typical embodiment of the invention described in the specification, a prismatic semi-membrane LNG tank is assembled within a support carriage surrounding the top and side walls of the tank and is connected to the tank by a plurality of load bearing insulating support blocks affixed to T-shaped beams on the tank and received in channel shaped members on the support carriage. The tank is assembled within the carriage which is slidably received within a temporary supporting structure and, when the tank has been completed, the integrated carriage and the tank are transferred to the hull of a ship or other permanent support structure. A pipe tower within the tank is affixed to the bottom wall of the tank and slidably connected to a tank dome at the top of the tank which is welded to the top wall of the tank. Stop members limit downward motion of the tank tower with respect to the top wall of the tank.

Abstract: In the vertical corner transition arrangement for semi-membrane tanks disclosed in the specification, curved horizontal sides plate of a semi-membrane tank wall are welded to one side of a vertical extruded aluminum modified I-beam with a vertical tapered stiffening corner block projection on the opposite side of the extruded aluminum I-beam, and the edge of a vertical unstiffened curved cylinder section is butt-welded to the projecting edge of the vertical tapered stiffening corner block. The curved plates of an orthogonally oriented semi-membrane tank wall are welded to one side of another vertical extruded I-beam member having a projecting vertical tapered stiffening corner block welded to the opposite side with a projecting edge which is welded to the opposite edge of the vertical stiffened curved cylinder section to complete the corner of the tank.

Abstract: In the embodiments described in the specification, permanent magnets are retained on a permanent magnet rotor rim by inverted U-shaped retainers and in one embodiment the outer surfaces of the retainers converge inwardly in the radially outward direction and engage corresponding surfaces of adjacent pole pieces which converge inwardly in the radially outward direction. In another embodiment the U-shaped retainers are affixed to the rotor rim by screws accessible through openings in the radially outer wall of the retainers and a further embodiment each retainer has outwardly projecting flanges which are affixed to the rotor rim by screws.

Abstract: In the particular embodiments of the invention described in the specification, a first signal generator produces a signal which changes in cycles having approximately straight line segments between maximum and minimum values at a first rate and a second signal generator produces a signal which changes in cycles having approximately straight line segments at a second rate which is an order of magnitude greater than the first rate. The maximum level of the second signal during any cycle is dependent upon the instantaneous signal level of the first signal and the minimum level of the second signal during any cycle is dependent upon a selected fraction of the instantaneous signal level of the first signal. The second signal is used to control the speed of a motor in a continuously changing random manner.

Abstract: In the magnet retention channel arrangement for a high speed rotor described in the specification, a rotor has an array of radially projecting, angularly spaced pole pieces and a magnet retention channel member inserted between each adjacent pair of pole pieces. Each magnet retention channel member is made of nonmagnetic material and has opposed side walls and an integral end wall at one end of the side walls and integral dovetail feet at the opposite ends of side walls. The channels contain permanent magnets and the side walls of uniform thickness with nonmagnetic feet within the core member couple the magnetic flux from the magnets to the pole pieces with substantially no magnetic discontinuities while the presence of the nonmagnetic end wall avoids magnetic shorting.

Abstract: In the typical embodiments described in the specification, a rolling element bearing arrangement includes an inner raceway with a curved outer surface facing in one lateral direction, an outer raceway with a curved inner surface facing in the opposite lateral direction, an array of rolling elements such as balls engaging the curved surfaces of the inner and outer raceways, a retaining ring in which the array of balls is received, and a retaining ring stabilizer urging the retaining ring in a lateral direction with respect to one of the raceways to inhibit vibration of the components. In addition, a vibration inhibiting outer ring member which may contain a heavy metal or a resilient material, is retained against the outer surface of the outer raceway by a composite wrap which may be a fiber-reinforced organic or inorganic polymer composite made by a dry layup, resin transfer molding, wet filament winding or preimpreganted filament winding technique.

Abstract: A fault tolerant synchronous machine has a stator with a core containing a plurality of phase windings, a rotor supported for rotation within the core, and a non-magnetic sleeve affixed to the stator and disposed in the space between the stator and the rotor and having a plurality of slots extending parallel to the axis of the rotor and positioned to receive high permeability inserts for shunting the flux paths of faulty stator windings to permit low power operation of a synchronous machine having faulty stator windings.

Abstract: In the magnet retention channel arrangement for a high speed rotor described in the specification, a rotor has an array of radially projecting, angularly spaced pole pieces and a magnet retention channel arrangement inserted between each adjacent pair of pole pieces. Each magnet retention channel arrangement has ferromagnetic side walls and a nonmagnetic alloy cap and nonmagnetic alloy dovetail feet affixed to opposite edges of the ferromagnetic side walls by welding or by a hot isostatic pressed powder metallurgy technique. The channels contain permanent magnets and the ferromagnetic side walls couple the flux from the magnets to the pole pieces with substantially no magnetic discontinuities and the nonmagnetic alloy cap and nonmagnetic core avoids magnetic shorting.

Abstract: In the embodiments described in the specification, a permanent magnet machine has a stator assembly containing a circular array of stator windings and a rotor assembly containing passages for permanent magnets and supported for rotation within the stator windings. The rotor assembly contains dummy magnet blocks in each passage during assembly of the rotor assembly in the stator assembly and a loading fixture containing energized permanent magnets is aligned with each passage in succession into which it supplies a row of permanent magnets while the dummy magnet blocks are removed by a retrieving fixture at the opposite end of the passage. After the permanent magnets have been inserted an end cover is mounted at each end of the passage to hold the energized permanent magnets in position.

Abstract: In the rotor arrangement disclosed in the specification a rotor has a central shaft with a surrounding rim to which a circumferential array of pole pieces is mechanically affixed by screws. An array of permanent magnets each mounted between an adjacent pair of pole pieces is radially retained in position by a slot wedge having edges shaped to interlock with the outer side portions of the adjacent pole pieces. The outer surfaces of the pole pieces and slot wedges form a uniform cylindrical outer surface which is covered by an outer wrap of fiber reinforced polymer material to assure that the magnets are retained radially in position.

Abstract: A modular transformer arrangement providing power to a multi-level power converter includes a plurality of three phase transformers having delta or extended delta connected primary windings and delta or extended delta or wye or zig zag wye connected secondary windings and the multi-level power converter has full bridge power modules inputs connected to isolated secondaries of the transformer modules and outputs connected in series and/or in parallel to provide increased voltage and/or current or multiple phases which can be phase shifted with respect to the input to the transformer.

Abstract: In the embodiment described in the specification, a fault tolerant motor drive circuit arrangement includes a motor having three stator windings which are electrically isolated and are supplied by separate single phase drive circuits, each having a differential current sensor detecting current in both circuit conductors and an overcurrent sensor in one circuit conductor, along with a ground connection for each circuit having a ground conductor with an overcurrent sensor and a high resistance with a voltage sensor across the high resistance. A monitoring unit receives signals from all of the differential current sensors, overcurrent sensors and voltage sensors to provide indications of the location of insulation faults or incipient faults in the windings.

Abstract: A PCM module arrangement includes a three phase circuit breaker and PCM electronics unit. Each phase of the circuit breaker has a Rogowski coil at the line side and load side contacts in a vacuum bottle and another zero sequence current sensor encloses the load side conductors of the circuit breaker to provide a zero sequence current signal. A PCM electronics unit is provided with phase current measurement signals from the Rogowski coils. The PCM electronics unit provides a direct interface for various signals including a signal from a supervisory control and data acquisition system.