Abstract: A wrist band for a device main body containing communication circuits, having a first wrist band at least partially covering a first antenna plate, a second wrist band at least partially covering a second antenna plate, and a clasp device including a contact mechanism for electrically connecting the first antenna plate and the second antenna plate to form a loop-like antenna when the second wrist band and first wrist band are clasped. The clasp device is releasable and has a three-fold stricture. The clasp device includes a clasp lower plate having a base end portion fixed to the first wrist band, a clasp intermediate plate connected to the clasp lower plate, a clasp upper box connected to the clasp intermediate plate and fixed to the second wrist band and a clasping lock mechanism that fixes the clasp upper box to the clasp lower plate when the clasp intermediate plate is rotated and overlapped onto the clasped lower plate.

Abstract: A circuit interrupter provides a conducting path between two conductors and interrupts the conducting path in response to overcurrent conditions in the conductors. The interrupter includes a magnetic core around which the conductors are disposed. Each conductor is electrically coupled to an arc runner and a spanner is biased into contact with the arc runners to compete a conducting path between the conductors. A secondary response mechanism is provided adjacent to the core and includes arms extending around the core and a magnetic body. In response to overcurrent conditions of a first magnitude the body of the secondary response mechanism is attracted to the core causing the arms to displace the spanner out of contact with the arc runners. In response to overcurrent conditions of a second magnitude, such as due to direct short circuits, the spanner is repelled rapidly to a non-conducting position and the secondary response mechanism is attracted to the core to hold the spanner in the non-conducting position.

Abstract: A modular primary surge protector assembly where various detachably connectable modules provide primary surge protection for different types of electrical lines. The modules are detachably connectable to a common bus which is permanently connected to a building ground wire.

Abstract: An electrical impulse suppressor comprising a band pass filter formed with strip transmission lines adapted to attenuate the flow of energy therethrough above and below a band limited range of frequencies. The suppressor used the impedance of a discharge means connected to a strip transmission live element to form the first of two resonant circuits used in the construction of the band pass filter.

Abstract: According to a field ground fault detector, a predetermined resistor is connected in series to a predetermined DC voltage. A DC voltage is applied between an N electrode side field circuit of a generator and a ground through the resistor. A voltage applied between terminals of the resistor is input to a low-pass filter. A voltage applied between the N electrode side field circuit and the ground is input to another low-pass filter. Output voltages of the low-pass filters are input to a level ratio determining circuit. The level ratio determining circuit outputs the determined result of the ground fault to the outside of the field ground fault detector corresponding to these voltages. Thus, even if the DC voltage varies or a higher harmonic voltage takes place in a generator of a thyristor exciting type, it does not affect the detecting sensitivity of the ground fault.

Abstract: An overvoltage protection circuit for a CMOS electronic multimeter circuit uses a pair of complementary field-effect protection transistors connected to each input line of the meter circuit. The gate electrodes of the protection transistors are connected to bias voltage sources which provide bias voltages with magnitudes slightly less than the meter power supply voltages. The protection transistors go into conduction when an overvoltage condition causes the voltage on the input to exceed the bias voltages and the conducting protection transistors clamp the input voltage to substantially the bias voltage. Current caused by an overvoltage condition is shunted to ground thereby avoiding a charging condition in the power supplies.

Abstract: A fusible link provided in a power supply of a computer system for providing evidence of an over temperature condition to document a fan failure in the event of catastrophic failure of the power supply. The power supply typically includes a temperature detection circuit often including a thermistor providing a signal indicative of an over temperature condition in the power supply. A latch circuit coupled to the temperature detection circuit shuts the power supply down in an attempt to prevent such catastrophic failure. In a circuit according to the present invention, a fuse is coupled to the temperature detection circuit where the fuse open-circuits when an over temperature condition is detected. Such blown fuse documents the over temperature condition. An external pin provided through a Zener diode and coupled to the fusible link enables external determination of the state of the fuse without disassembling the power supply.

Abstract: A local area network (LAN) interface port with a simple overcurrent protection circuit which isolates the power supply connection for the port from fault conditions on the LAN. The circuit has a normally-on field effect pass transistor in line with the load terminal. The pass transistor shuts off when a fault condition is detected. Such a condition is detected when the voltage across a sense resistor becomes greater than the voltage across a reference resistor. A current mirror is made up of a transistor array and the sense and reference resistors. The current mirror compares the two voltages, and a bipolar transistor switches the gate voltage of the pass transistor on when the fault condition is detected. The design is particularly useful with the LAN system specified in ANSI/IEEE Standard 802.3, commonly known as Ethernet.

Abstract: A fault current protection system for a traction vehicle propulsion system including a synchronous generator having armature and field windings and power conditioning circuitry connecting the generator armature windings to a traction motor employs a normally charged capacitor which, in response to a fault signal resulting from excess current in the generator armature windings, is electrically switched into parallel with the excitation current source connected to the generator field windings so as to discharge through the generator field windings and commutate the excitation current source.

Abstract: A shorted diode protection system for a traction vehicle propulsion system including a synchronous generator having armature and field windings and a bridge rectifier circuit coupling the generator armature windings to a traction motor employs a normally non-conducting solid-state controllable electric valve in parallel with the generator field windings. When a rectifier diode of the bridge rectifier circuit fails short, an a-c current is reflected into the generator field winding circuit. Upon detection of this reflected current, the valve is switched into a conducting state, thereby limiting the voltage on the generator field windings.

Abstract: A modem located on a PC card. An I/O socket is mounted on one end of the PC card and sideswipe contacts are positioned long e one or more sides. The I/O socket has a plurality of positions including one or more positions which are electrically connected to the modem. A relay is located in the PC card, and has one side connected in common to the modem and the positions on the I/O socket. The other side of the relay is connected to the sideswipe connectors. The control input to the relay is connected to a position of the I/O socket separate from the modem positions. A voltage source is connected to a position in the socket separate from the modem positions and the control signal position. An I/O plug is designed to have one side connected to the telephone network and the other side connected to the I/O socket such that all pins in the plug mate with the corresponding positions in the I/O socket.

Abstract: The power supply, useful with an electromagnetic force apparatus such as a riveter or a bolt inserter, includes two capacitor banks which are charged through charging doubler modules. Each charging doubler module includes an AC capacitor which is responsive to a power source. The AC capacitor is connected to a node point between two diode elements, which are connected in series across the capacitor bank. An analog-to-digital converter converts the voltage on the capacitor bank to a digital voltage for comparison with a selected digital charge voltage in a controller. The selected digital charge voltage may vary over time by means of a compensating algorithm. A ground fault indicator using a biasing voltage is connected between a selected electrical circuit portion of the force apparatus and earth ground. A gas discharge tube in combination with a current sensing element is connected to the capacitor banks to determine a possible over-voltage condition.

Abstract: A system of protection which utilizes a simple circuit for the detection and isolation of single and multiple phase to phase and phase to neutral faults between a multi-phase source of electrical energy and a power conversion device driven therefrom. The circuit comprises a current transformer positioned at the neutral aspect of each phase winding of the multi-phase source of electrical energy. These current transformers sense the current generated by the source of electrical energy and produce a signal of proportional magnitude thereby. These proportional sense signals from each of the individual current transformers are transmitted to a controller which vectorially adds these signals to produce a single summed output signal. The controller monitors the percent ripple content of the summed output signal and generates an output protection signal if the percent ripple content of the monitored summed output signal exceeds a predetermined threshold value for a predetermined time interval.

Abstract: A power supply polarity reversal protection device includes a voltage controlled switching device, e.g. an N-channel MOSFET connected between the power supply output (e.g. a positive supply voltage) and the circuit to be powered by the supply, i.e. the load. A diode, preferably the parasitic diode inherent in the MOSFET between the drain and source, is arranged so that when the positive supply terminal is connected to the transistor, the diode is forward biased and will allow a diode current to flow. A sensing means generates a control terminal voltage in response to the diode current flow. This control terminal voltage is applied to the switching means control gate and is sufficient to cause full conduction through the switching means. If, instead, a negative supply voltage is connected to the transistor, the diode will be reverse biased and no current will flow.

Abstract: A method and apparatus for avoidance of power-up current surge upon activation of a current supply device under inductive effect. An alternating-current switch is connected in series with the current supply device and a phase cut-in circuit is provided for enabling adjustable connection of the current supply device with the mains alternating voltage starting with the instant of powering up with equal-size unipolar phase segments. A switching unit is provided for activation of the phase cut-in circuit so that a predetermined number of the equal-size unipolar segments can be produced. An oppositely poled half wave which follows in time immediately is switched with an ignition signal of 170 to 180 degrees. In the phase cut-in circuit, respectively, an ignition signal is produced at the predetermined phase cut-in angle in the half waves following this half wave.

Abstract: A leak detector and circuit interrupter for detecting the presence of a liquid in the base of a dispenser containment box and interrupting the supply of electrical power when such liquid is detected is disclosed. There is a user enableable circuit for selectively enabling the pump and an override circuit which is operable when enabled to disable the user enableable circuit. An optical liquid sensing probe is positioned near the bottom of the containment box with optical coupling to the override circuit. The optical probe is coupled to a light emitting diode, a photosensitive transistor, and includes a light path with at least one total internal reflection surface normally coupling the light emitting diode and the photosensitive transistor. The probe normally maintains the override circuit in an ineffective state, but, when the light path is interrupted by an accumulation of liquid in the bottom of the containment box, changes state thereby enabling the override circuit and disabling the pump.

Abstract: A thermal protector for a hermetic electrically-driven compressor including a hermetically sealed housing in which a power-supply terminal, an electric motor and a compressor are enclosed with a predetermined amount of refrigerant gas is disclosed. The thermal protector includes a thermally responsive switch having first and second lead terminal pins for securing first and second connecting terminals respectively and a holder formed from an electrically insulating material and including first, second and third cavities. Each of the first and second cavities has an opening in its one side. The first cavity accommodates the thermally responsive switch while the second cavity accommodates a secured portion between the lead terminal and the connecting terminal with a hardenable electrically insulating filler filling up the second cavity. Alternatively, the second connecting terminal is secured to a wall of the holder by an insert molding so as to extend through the wall, instead of use of the filler.

Abstract: A simplified and economical power supply for redundant computer systems of control systems is disclosed. These control systems may include burner control for furnaces. The safety and reliability of the system are increased. The power supply comprises one single common voltage supply in the form of a self-monitoring power pack unit SN having a power pack NT, an undervoltage monitor UW and an overvoltage monitor. The self-monitoring power pack unit communicates with the redundant computer units P1, P2 via a supply line 1e. This single self-monitoring power pack unit is used according to the invention instead of the known fully parallel two-channel operation with two computer units and two power packs with appertaining components and supply lines. The overvoltage monitor UW and the undervoltage monitor UW are preferably checked for operability through the periodic transmission of a test signal.

Abstract: A low voltage power supply and distribution center comprises a housing (12) having three internal compartments including: a high voltage compartment (17), a low voltage distribution compartment (19), and a transformer compartment (21). The housing (12) is designed for surface or recessed mounting on or in a wall or ceiling. For recessed mounting, with the housing (12) surrounded with 20 cm (8 inches) of insulation, the maximum surface temperature of the housing is less than 90.degree. C. The three compartments (17,19,21) are formed by a removable power tray (15) having a torodial transformer (132) mounted thereon. The low voltage compartment (19) comprises a fuse panel (150) for mounting a plurality of plug-in fuses (153) from which the low voltage power is distributed. The high voltage compartment (17) comprises a switch or a dimmer (131) in a high voltage line between the transformer (132) and the incoming high voltage line, or the dimmer or switch may be remotely installed on a wall.