Abstract: A method and apparatus for detecting electrical arcs in an electrical system having a periodic power supply is disclosed. A method according to the invention compares instantaneous values of a monitored waveform both with (a) their past values at corresponding phases of the AC supply waveform, and (b) their future values at corresponding phases of the AC supply waveform. The monitored waveform is delayed or stored to allow such comparisons in near real time, to produce an output which is only slightly delayed behind the monitored waveform. An apparatus according to the present invention discloses a sampling circuit that samples electrical signals indicative of transient load conditions to produce a sampling circuit output. A storage device receives the sampling circuit's output and stores a time history of that output over an interval.

Abstract: A system for arc detection testing using synthesized arcs is disclosed, which uses voltage and current waveform generators to generate an arc's analog form voltage and current waveform from a digital form of the arc's captured waveforms. A voltage waveform amplifier and a current waveform amplifier are included, with the outputs of the voltage and current waveform generators coupled to the inputs of the voltage and current waveform amplifiers, respectively. The outputs of the voltage and current waveform amplifiers are connected in circuit to a device under test to test the device's response to the waveforms. A method for testing a device's response to a simulated arcing condition is also disclosed. An electric arc's voltage and current waveforms are captured in digital form. Analog form voltage and current waveform are generated from the captured digital voltage and current waveforms.

Abstract: Electric arc monitoring is effected by exploiting the discovery that electric arcs are fractal phenomena in that all essential information that signifies “arc” is contained in each fractal subset. These fractal subsets are logarithmically distributed over the arc spectrum. Monitoring of arcs is most advantageously effected on a fractal subset (16) of low logarithmic order where the amplitude is higher pursuant to the 1/f characteristic of electric arcs, where cross-induction among neighboring circuit is lower, and where travel between the arc (12) and the arc signature pickup (23) is longer than at the high frequencies customary for electric arc detection. Fractal subset transformation (17) reduces the danger of false alarms. Arc signature portions may be processed in out of phase paths (242, 342) or treated as modulated carriers (42) for monitoring.

Abstract: Electric arc monitoring is effected by exploiting the discovery that electric arcs are fractal phenomena in that all essential information that signifies an “arc” is contained in each fractal subset. The fractal subsets are logarithmically distributed over the arc spectrum. Monitoring of arcs is most advantageously effected on a fractal subset of low logarithmic order where the amplitude is higher pursuant to the 1/f characteristic of electric arcs, where cross-induction among neighboring circuits is lower, and where travel between the arc and the arc signature pickup is longer that at the high frequency customary for electric arc detection. Fractal subset information reduces the danger of false alarms. Arc signature portions may be processed in out of phase paths or treated as modulated carriers for monitoring.

Abstract: Electric apparatus having distinct electric terminals has an input power terminal of electrically insulating material, including a base of electric insulating material having a first electric terminal base portion and a second electric base portion spaced from that first electric base portion, and a barrier wall of insulating material on that base acting as an isolator between the first and second electric terminals on these base portions, and preferably also as a standoff for a protective cover. A plurality of electric fuse holders in that or other electric apparatus may be mounted in mutually spaced relationship, and a heat sink including a frame around that plurality of mutually spaced electric fuse holders is in heat-transfer relationship with these electric fuse holders, and includes a cross-piece between each adjacent pair of the mutually spaced electric fuse holders.

Abstract: A system for arc detection testing using synthesized arcs is disclosed, which uses voltage and current waveform generators to generate an arc's analog form voltage and current waveform from a digital form of the arc's captured waveforms. A voltage waveform amplifier and a current waveform amplifier are included, with the outputs of the voltage and current waveform generators coupled to the input to inputs of the voltage and current waveform amplifiers, respectively. The outputs of the voltage and current waveform amplifiers are connected in circuit to a device under test to test the device's response to the waveforms. A method for testing a device's response to a simulated arcing condition is also disclosed. An electric arc's voltage and current waveforms are captured in digital form. Analog form voltage and current waveform are generated from the captured digital voltage and current waveforms.

Abstract: An equipment mounting rack is composed of a seismically sound skeleton structure having spaced vertical uprights supplemented by distinct spaced equipment mounting structures attached to that skeleton structure and extending along these vertical uprights and constituting side wall structures of a mounting rack interior space. The distinct spaced equipment mounting structures may have elongate first sections extending along the spaced vertical uprights, and elongate second sections extending along these first sections and constituting side wall structures of a mounting rack interior space. Cabinet walls may be attached to the skeleton structure, and the equipment mounting structures may constitute inside such cabinet walls side wall structures of a mounting rack interior space. The vertical uprights advantageously are reinforced by elongate partial enclosures that may avoid the need for a large number of weakening mounting holes in these uprights.

Abstract: An equipment mounting rack is composed of a seismically sound skeleton structure having spaced vertical uprights supplemented by distinct spaced equipment mounting structures attached to that skeleton structure and extending along these vertical uprights and constituting side wall structures of a mounting rack interior space. The distinct spaced equipment mounting structures may have elongate first sections extending along the spaced vertical uprights, and elongate second sections extending along these first sections and constituting side wall structures of a mounting rack interior space. Cabinet walls may be attached to the skeleton structure, and the equipment mounting structures may constitute inside such cabinet walls side wall structures of a mounting rack interior space. The vertical uprights advantageously are reinforced by elongate partial enclosures that may avoid the need for a large number of weakening mounting holes in these uprights.

Abstract: An electric switching device is assembled with an electric terminal and a power panel having a first side at the electric switching device and second side at the electric terminal. The electric switching device has a prong, and a receptacle is made for that prong. That receptacle is provided with an external catch for a detent. The power panel is provided with an aperture having a detent for the catch. A flexible electric conductor is connected to that receptacle at a safe distance from the power panel and any power busses and that flexible electric conductor is connected to the electric terminal. The receptacle is inserted into the aperture from the second side of the power panel until the catch catches the detent. The electric switching device is assembled with the power panel by insertion of the prong into the receptacle.

Abstract: Systems of monitoring electric arcs substantially eliminate alternating current fundamentals and harmonics from monitored arc signatures. Such systems phase shift, delay or otherwise store a representation of the alternating current fundamental and harmonics, and substantially purge such alternating current fundamental and harmonics from the arc signatures with the stored representation of such alternating current fundamental and harmonics, while substantially preserving chaotic arc signature components. Electric arcs are then monitored from such purged arc signatures. Imperfections in such purging are detected and corrected for a provision of detectable arc signature components free of fundamentals and harmonics that could cause malfunction and false alarms.

Abstract: Electric arc monitoring is effected by exploiting the discovery that electric arcs are fractal phenomena in that all essential information that signifies an “arc” is contained in each fractal subset. The fractal subsets are logarithmically distributed over the arc spectrum. Monitoring of arcs is most advantageously effected on a fractal subset of low logarithmic order where the amplitude is higher pursuant to the 1/f characteristic of electric arcs, where cross-induction among neighboring circuits is lower, and where travel between the arc and the arc signature pickup is longer that at the high frequency customary for electric arc detection. Fractal subset information reduces the danger of false alarms. Arc signature portions may be processed in out of phase paths or treated as modulated carriers for monitoring.

Abstract: A circuit board holder has or is provided with a face plate and with walls projecting from an inside of that face plate. A pair of opposite ones of such walls are equipped with circuit board retainers. Such retainers may be inside and/or outside of a space in the circuit board holder. The circuit board holder is equipped with one or more holder retainers or resilient snaps for releasably retaining that circuit board holder in an aperture of a panel. Such holder retainers or resilient snaps may have serrations for engaging panels of different thicknesses at their apertures. Such panel may be provided with a slot or slots at that aperture for access to the holder retainer or resilient snaps through the panel. The holder retainer or resilient snap may be released through such slots, such as by screwdrivers or other release tool, for removal of the circuit board holder or similar device from the panel.

Abstract: Electrical equipment is housed in a cabinet and is protected against hurricane-force calamities by covering the electrical equipment with an inner door system inside the cabinet, and by closing an opening of the cabinet with an environmental door system, and overlaying that environmental door system with a calamity-proof door system that may be used as an on-site temporary roof for installation and service personnel in an upturned position, and that constitutes a protection against hurricane-force calamities in a closed position on the shut environmental door system.

Abstract: A method of monitoring electric battery capacity effects evaluation of battery capacity in terms of battery current and battery voltage in a succession of monitoring cycles, scales down an influence of battery current on the evaluation as the succession of monitoring cycles, progresses, and scales up an influence of battery voltage on such evaluation as the succession of monitoring cycles progresses. A similar method effects an assessment of battery capacity during alternating battery discharge operations and battery charging operations over a recurrence of monitoring cycles, detects a decline of attainable battery charge capacity during battery charging operations, and modifies its assessment in response to the detected decline of attainable battery charge capacity.

Abstract: An equipment rack has horizontal frame structure, and vertical frame structure of sheet material, secured to that horizontal frame structure and having a bent cross-section and opposite ends. The bent cross-section has a square-wave configuration including alternate first, second and third square half-cycle configurations in one piece presenting three substantially flat and mutually spaced crests. The horizontal frame structure extends into more than one of these square half-cycle configurations and along the substantially flat crests of the latter square half-cycle configurations in overlapping relationship with the vertical frame structure substantially for the widths of the crests and for corresponding heights of the horizontal and vertical frame structures. The horizontal and vertical frame structures are intimately interconnected along the above mentioned opposite ends and at all overlapping portions of the horizontal and vertical frame members.

Abstract: A cabinet has a top, an opposite bottom, a front, an opposite rear, and sides extending between that front and that rear for containment of electrical equipment requiring different groups of electric conductors. One of these sides is segmented between the front and the opposite rear into separate conductor channels for different groups of electric conductors, and that one side is provided with a removable cover structure for the conductor channels permitting access to these conductor channels from space adjacent that one side between the front and the opposite rear. Different ones of these groups of electric conductors may be arranged side by side in one of these sides between the front and the opposite rear.

Abstract: A principal object of the invention is to detect sparks or arcs (12) in electric circuits (13) or otherwise to detect a spectrum of a broad band of distinct instaneous radio frequencies in radio frequency noise. The invention rejects extraneous narrow-band signals having frequencies within the broad band, such as by means of filters (21, 27, 29) or a balanced mixer arrangement (32-39 ) . The mixer 37 may be fed from a radio frequency signal duplicator (32, 33, 34) having an input (25) coupled to a source of the spectrum, a first output for one spectrum as duplicated by that duplicator connected to one mixer input (35), and a second output for the other spectrum as duplicated by that duplicator connected to tile other mixer input (36). Alternatively, the radio frequency mixer (37) may receive the output of a wide band noise generator (68) at its other input (36, FIG. 5 ).

Abstract: A principal object of the invention is to detect sparks or arcs (12) in electric circuits (13) or otherwise to detect a signal having a spectrum of a broad band of distinct instantaneous radio frequencies in radio frequency noise. The invention rejects extraneous narrow-band signals having frequencies within the broad band, such as by means of filters (21, 27, 29) or a balanced mixer arrangement (32-39). The mixer 37 may be fed from a radio frequency signal unbalanced to balanced converter (32) having an input (25) coupled to a source of the signal having the spectrum and having balanced outputs connected to the mixer inputs (35, 36). Alternatively, the radio frequency mixer (37) may receive the output of a wide band noise generator (68) at its other input (36, FIG. 5).

Abstract: A supporting structure of one piece of sheet material constituting a top and several legs depending from that top in one piece has for each of these several legs an angled profile of that one piece of sheet material and in one piece with the top across the entire profile. Such supporting structure may be made of a blank of sheet material forming a pattern having a central portion for the top, first and second portions projecting from a first side of that central portion for first and second legs, third and fourth portions projecting from an opposite second side of the central portion for third and fourth legs, and first and second side panel portions projecting from opposed third and fourth sides of the central portion. These first, second, third and fourth portions are provided, respectively, with lateral ledges of which each is spaced from an adjacent one of the first and second side panel portions by a notch for a butt joint of each of the lateral ledges with an adjacent side panel portion.

Abstract: An electronic equipment rack including a horizontal frame member and a vertical frame member is braced against earthquake damage by means of a metal gusset having a first leg fitting against the horizontal frame member to extend along part of that horizontal frame member, a second leg fitting against the vertical frame member for a first part of that second leg to extend along part of that vertical frame member, a third leg spaced from and extending in parallel to a second part of the second leg, and a fourth leg extending between the second and third legs to abut against another part of the vertical frame member. Solid metal is carried from the vertical frame member to the horizontal frame member by intimately connecting the gusset to the vertical and horizontal frame members.