Abstract: For evaluating the condition of a first lightning arrester of the gapless metal-oxide varistor type that is connected across the high voltage winding of a transformer, I connect externally of the transformer a second arrester of the same type, but with means for selectively changing its breakdown voltage between a first value that is higher than the normal breakdown voltage of the first arrester and a second value that is lower than said normal breakdown voltage. Pulses are applied to the low voltage winding of the transformer while the second arrester has its breakdown voltage set at the first value and while said breakdown voltage is set at said second value. By determining whether or not the second arrester conducts in response to each of these pulses, it can be established whether the first arrester is then undamaged, damaged in a shorted mode, or damaged in an open mode.

Abstract: An improved electrical bushing is disclosed which includes, in combination, an insulating body of a polyester material, a current-carrying stud, and an adhesive coating applied to the grooved peripheral surface of the stud. The bushing is manufactured by applying the adhesive coating to the peripheral surface of the stud. The polyester insulating body is then molded about the stud. Heast is applied to concurrently cure the polyester body and adhesive coating to achieve a bonded, fluid-tight seal between the stud and the insulating body.

Abstract: A laminated amorphous-metal transformer core having four sides joined by corner regions includes (a) joints located in a joint region in one of its sides and (b) side portions between the joint region and two corner regions. After annealing the core and while restraining the core laminations in a core region remote from the joint region, the joints are separated by displacing each of the side portions into a position of approximate alignment with the side of the core interconnected therewith at a corner region. Then a splint is applied to each of the side portions and the aligned interconnected side, thus holding these two parts in approximately aligned relation. The splint is relied upon to facilitate insertion of the aligned parts into the window of a coil, following which the splint is slid off the aligned parts, and core-lacing is completed.

Abstract: This transformer comprises preformed coil structure and a wound core of closed-loop configuration extending about a window and having joints in a localized region thereof that allow the core to be opened at the joints to permit insertion into the window of the preformed coil structure. The core comprises superposed laminations of thin amorphous ferromagnetic strip material which extend around the core from the localized joint region. The laminations include predetermined portions adjacent the joints that are displaced to provide a wide opening into the core window for insertion of the coil structure. A coating of adhesive bonding agent applied before said displacement is present on the lateral edges of the laminations in regions of the core not including said predetermined portions, thereby holding the laminations in correct assembled relationship when the core is opened, yet without interfering with displacement of said predetermined portions.

Abstract: A protective relay, for use in protecting a predetermined protected zone of a three phase alternating current electrical power transmission line, the relay being of the type which receives a comparison signal from a remote relay by way of a communication channel, includes circuitry for detecting abnormalities in the received comparison signal. Such abnormalities are caused by, for example, errors in the communication channel, non-fundamental frequency components in the secondary current caused by current transformer saturation, and high frequency transients in the protected zone. The abnormalities are detected by subtracting a filtered demodulated signal having a frequency which is substantially equal to a fundamental frequency of the comparison signal, from an unfiltered demodulated signal. The resulting difference is a signal which comprises components caused by the abnormalities.

Abstract: A first annular form used for making a transformer core is wound from a strip of amorphous ferromagnetic material and is thereafter cut. The resulting laminations are then arranged in a second annular form with distributed gap joints, each joint involving a plurality of superposed laminations. The second annular form is then formed into a rectangular shape core and is then annealed. Then a bonding agent is applied to the transverse edges of the laminations over a region of the core removed from the joints. The joints are then separated to open the core, allowing displacement of unbonded regions of the core. Thereafter, preformed coil structure is inserted into the window of said opened core to surround a portion of the core. Then the unbonded regions of the core are returned to their original positions to remake the joints.

Abstract: To reduce the material in a transformer core and winding assembly, the edges of the core winding legs are relieved so as to achieve improved conformity with the inside corners of the coils disposed thereabout. More intimate spacing of the coils relative to the legs is therefore accommodated with consequent material savings in both the core and the winding coils. Methods for relieving the leg edges by bevelling and notching are disclosed.

Abstract: A characteristic timer, for a protective relay which provides protection for a portion of an AC transmission line, exhibits a phase characteristic which is always integrating and a ground characteristic which changes from non-integrating to integrating as a function of input signal pulse width and a preselected cut off time. The ground characteristic begins to integrate upon expiration of the preselected cut off time or if the input signal pulse width exceeds a predetermined check level of magnitude during the cut off time. If the pulse width magnitude of the input pulse is less than or equal to the predetermined check level magnitude during the cut off time, the characteristic will be non-integrating.

Abstract: A phase comparison type ground distance relay for a predetermined phase of three-phase AC transmission line includes a phase coincidence detector responsive to phase coincidence between an operating signal and a plurality of polarizing signals. Zero suppression networks are utilized for deriving second and third polarizing signals in order to improve discrimination between internal and external faults; thereby increasing the reliability of the relay operation and the security of the protection system. The second polarizing signal comprises that portion of a signal which exceeds a predetermined threshold value and which is related to the product of a signal proportional to the net current flowing in all three phases of the power system and the positive sequence replica impedence of the transmission line.

Abstract: A transformer comprises a tank containing insulating liquid, and within the liquid there is an amorphous-alloy laminated core that comprises spaced-apart upper and lower yokes and two spaced-apart legs at opposite ends of the yokes. Coil structure surrounds the legs, locating the yokes outside the coil structure. Box-like enclosures primarily of electrical insulating material respectively enclose the yokes in positions outside the coil structure. The enclosure about the lower yoke is positioned to capture therein chips of amorphous alloy which might become detached from said core and fall toward the bottom of the tank.

Abstract: A transformer core is disclosed having one or more winding legs built up from a plurality of silicon steel laminations and a pair of yokes built up from a plurality of amorphous steel laminations. The yokes and legs are serially joined by silicon steel-amorphous steel lamination joints to create a magnetic loop circuit and thus provide a transformer core having significantly improved core loss characteristics as compared to a power transformer core formed exclusively of silicon steel laminations.

Abstract: This transformer comprises a generally rectangular core having two yokes and two legs connecting the yokes, with joints located in one of the yokes. Coil structures surround the two legs. Flexible banding under tension applies clamping forces to two clamping plates spaced outwardly from the yokes, and these clamping forces are transmitted to the coil structures by paths bypassing the core. The banding extends alongside the legs and is oriented so as to engage the core at opposite ends of said one yoke but so as to be spaced from the core at opposite ends of the other yoke.

Abstract: A battery charger having a housing, a transformer in the housing and separate sets of external terminals situated on recessed surfaces at opposed sides of the housing, the external terminals being connected to separate secondary windings of the transformer so that the terminal sets are oppositely phased electrically. Blade connectors spaced apart along the line of spacing between opposed sides are electrically connected to the primary winding and extend through the housing for acceptance by an external electrical receptacle. A grounding pin being mechanically affixed to the transformer core structure and similarly extending through the housing.

Abstract: To reduce the material in a transformer core and winding assembly, the edges of the core winding legs are relieved so as to achieve improved conformity with the inside corners of the coils disposed thereabout. More intimate spacing of the coils relative to the legs is therefore accommodated with consequent material savings in both the core and the winding coils. Methods for relieving the leg edges by bevelling and notching are disclosed.

Abstract: A demodulating apparatus receives a differential phase shift keyed analog signal which is coupled to the input of a voltage controlled oscillator. The voltage controlled oscillator generates a plurality of pulses at a frequency which is proportional to the amplitude of the analog signal. The pulses are counted during in-phase intervals and intervals which are quadrature phase related to the in-phase intervals. The signs of the differences between (i) the number of in-phase and quadrature phase interval pulses counted during a first bit rate interval and (ii) a reference pulse count number, are determined. The signs of the differences between (i) the in-phase and quadrature phase pulses counted during a second bit rate interval, which follows the first bit rate interval, and (ii) the reference count number, are also determined.

Abstract: A charging system is provided for use in an energy-using device operable from an external source of A-C power and from either batteries of either the rechargeable or non-chargeable type. The charging system effects charging of batteries of the rechargeable type upon connection of the energy-using device with the external source of A-C power. The charging system includes a charging adapter for insertion with rechargeable batteries into the energy-using device. Removal of the charging adapter from the energy-using device is effective to preclude charging of batteries of a non-rechargeable type.

Abstract: A battery charging system is provided including a charger and a rechargeable battery of "standard" size and configuration. The rechargeable battery bears a special indicia that is sensed by the charger as a precondition to enabling the charging circuit of the charger. The indicia-bearing battery can thus be used in place of "standard" non-rechargeable batteries in battery using products of various sorts, but non-rechargeable batteries, lacking the special indicia, cannot be charged in the charger. Potential damage to the charger or product and other adverse effects associated with charging of non-rechargeable batteries is thus avoided.

Abstract: A charging system for rechargeable batteries, e.g. of the 9 volt type, includes a charger and an adapter module for mechanically and electrically interconnecting the charger to a 9 volt size battery. The adapter includes a projection or key extending upwardly from and adjacent the battery terminals to block connection of all batteries except those batteries with key receivers. In this manner, only rechargeable batteries with such receivers may be charged thereon. Finger grips on the adapter are designed to generate a moment for detachment from the charger.

Abstract: A compacted powdered iron core utilizes iron powder in the 0.002 to 0.006 mean particle size range which is first coated with an alkali metal silicate and then overcoated with a silicone resin polymer. The treated powder is compressed to approximately 94% of theoretical density and then annealed at approximately 600.degree. C. This results in a core component characterized by overall core losses as low as in conventional laminated cores in A.C. operation.

Abstract: A compacted powdered iron core utilizes iron powder in the 0.002 to 0.006 mean particle size range which is firt coated with an alkali metal silicate and then overcoated with a silicone resin polymer. The treated powder is compressed to approximately 94% of theoretical density and then annealed at approximately 600.degree. C. This results in a core component characterized by overall core losses as low as in conventional laminated cores in A.C. operation.