Abstract: A slot closure arrangement for closing the slot opening of slots in the stator of a dynamoelectric machine and for providing a restraining force against conductors in the slot. The slots have opposing notches on opposite sides of the slot adjacent the slot opening. A flat rectangular spring member is placed in the slot opening with the opposite edges of the flat spring member each terminating in one of the opposing notches. A pair of wedges with complementary tapered surfaces is inserted between the spring member and the surface of the conductor in the slot adjacent and facing the slot opening. The wedges are advanced one over the other to increase the overall thickness. The surface of the wedge engaging the spring member has a thickness at the center greater than the thickness at the edges, and the center presses the spring member outwardly when the wedges are advanced, deforming the spring member which then provides a force through the wedges against the conductor in the slot.

Abstract: An infra-red telemetry system for transmitting information between a rotating shaft of a dynamoelectric machine and an adjacent stationary location includes a plurality of sources of infra-red radiation spaced equi-distanced from one another around the shaft of the dynamoelectric machine and mounted to the shaft of the machine. Information is coded into a pulse train and the pulse train is used to energize the infra-red sources simultaneously. At least one infra-red detector is mounted at a stationary location adjacent the dynamoelectric machine. The infra-red sources are directed to bounce their radiation off a cover plate having a diffuse reflecting surface and mounted on the rotor of the dynamoelectric machine. The bounced radiation is detected by the infra-red detector and decoded to provide the information from the rotor.

Abstract: A thermal model of an electric apparatus such as a transformer or motor, from which signals can be obtained representing temperatures of the conductors and of the adjacent core material, includes storing first and second values, respectively, representing conductor temperature and core material temperature. The magnitude of the current(s) in the apparatus is sensed and a digital signal representative thereof is added to the first value to represent heat generated in the conductors. Values are determined for both heat transferred from the conductors and heat transferred into the apparatus core based on the difference in the first and second values. The value representing heat transferred from the conductor is subtracted from the first value to give a new first value and the value representing heat transferred to the core is added to the second value.

Abstract: A slot closure arrangement for closing the slot opening of slots in the stator of a dynamoelectric machine and for providing a restraining force against conductors in the slot. The slots have opposing notches on opposite sides of the slot adjacent the slot opening. A flat rectangular spring member is placed in the slot opening with the opposite edges of the flat spring member each terminating in one of the opposing notches. A pair of wedges with complementary tapered surfaces is inserted between the spring member and the surface of the conductor in the slot adjacent and facing the slot opening. The wedges are advanced one over the other to increase the overall thickness. The surface of the wedge engaging the spring member has a thickness at the center greater than the thickness at the edges, and the center presses the spring member outwardly when the wedges are advanced, deforming the spring member, which then provides a force through the wedges against the conductor in the slot.

Abstract: A fuse element is a ribbon of aluminum or aluminum alloy having a terminal at each end of the ribbon. Each terminal is made of copper sheet material having a portion that is tin plated. The tin plated portion is folded over the end of the ribbon to contact both sides and is welded to the ribbon to form a connection capable of carrying short circuit currents and able to withstand repeated temperature changes. Preferably the weld consists of three side-by-side spot welds extending on either side of the ribbon to the respective tin plated terminal portion.

Abstract: A combination fuse has a current limiting section and a low current expulsion section with the expulsion section within the high current section. This arrangement makes it possible to increase the length of the expulsion tube as compared to the prior art and provide greater arc cooling without increasing the overall length of the fuse. In addition the fuse arrangement places one fuse terminal between the ends of the fuse rather than at one end as in the prior art, thereby reducing the strain on the mounting means and the tendency to vibrate. The expulsion section includes an expulsion tube with a standard fuse link inside. The expulsion tube is mounted within the casing of the current limiting section to an end closure at one end of the casing. The expulsion tube projects through an end closure at the other end of the casing. A connector terminal is mounted to the casing adjacent the end from which the expulsion tube projects.

Abstract: A current limiting fuse has a helically coiled fuse element of ribbon-like material extending within a tubular casing between metallic end caps. The ribbon-like material is edge on to the axis of the helix for permitting a greater length of fuse element than if the ribbon-like material had its flat side towards the axis. In a preferred form, the ribbon-like material has ripples or indentations across it with the ripples having a greater displacement at the edge of the ribbon-like fuse element nearer the axis.

Abstract: A speed switch for a motor has an electrically conductive disc which rotates with the rotor of the motor. A drag member adjacent the disc is mounted for limited pivotal movement and has a permanent magnet linked magnetically with the disc to cause electromagnetic interaction resulting in a force on the drag member which varies with the speed of rotation of the disc. A switch is operated by a movement of the drag member to actuate an alarm or to actuate a protective device for the motor. An improved latching means restrains the drag member from movement until a predetermined rotational speed of the disc is reached. A screw is mounted so that it can be advanced into the gap and withdrawn therefrom to provide a finely adjustable magnetic shunt. The adjustment of the shunt varies the magnetic latching force and thereby the speed causing actuation of the switch.

Abstract: A magnetic amplifier having a magnetic core in the shape of a hollow cylinder is provided with a gate winding comprising series-connected coaxial conductors passing through the center of the hollow core.

Abstract: In an electrical substation, the use of separate towers or poles to terminate overhead lines is obviated by using bus duct for this purpose. Isolated phase or metal-clad bus duct is erected to provide not only the electrically conductive path between the overhead lines and the associated electrical equipment, but also the mechanical strength necessary in order to eliminate the towers and poles of the prior art.

Abstract: A dynamoelectric machine has a stator and a discoidal rotor with an axial air gap between them. The machine has a permanent magnet field structure wherein each flux-producing component comprises a mosaic of at least one layer of two or more unit permanent magnets per layer.

Abstract: A discoidal winding structure for an axial gap dynamoelectric machine is made in segments. Each segment is in the general shape of a sector of the discoid and contains a fraction of the total number of winding coils, and these coils are bonded together with a resinous material into a rigid structural member. Means are provided for securing the segments together in a rigid discoidal winding structure.