Abstract: A control system and method for sectionalizing switches and pulse-testing interrupter/reclosers in a distribution grid feeder which enables fault location, isolation and service restoration without requiring an external communications infrastructure to pass information between the switches. The method includes switches entering an armed state when they experience a high fault current during an initial fault event. Then, when the interrupter/recloser runs its test pulse sequence, any armed switch counts all test pulses as fault pulses, while non-armed switches count the test pulses as load pulses. Switches open to isolate the fault based on threshold values of fault pulse count and load pulse count. When an initially active interrupter/recloser completes its test pulse sequence, another interrupter/recloser begins its sequence, and all switches reconfigure their threshold values based on the new interrupter/recloser.

Abstract: The present invention discloses a position-sensorless control method for a brushless motor, the method including: turning off a first driving voltage of a first phase coil, and within detection time, detecting a back electromotive force of the first phase coil; determining a reference phase and a cycle of a second driving voltage according to the back electromotive force; determining a pulse width modulation signal according to the reference phase and the cycle; and determining to provide the second driving voltage for the brushless motor according to the pulse width modulation signal, the second driving voltage being used to drive the brushless motor. The present invention effectively reduces the cost, decreases implementation difficulty and increases system performance and reliability.

Abstract: A leakage detector is provided with the addition of an output control circuit that monitors a circuit wire-to-ground voltage, which is at the root of a suffered operation and produced between a transformer B-class grounding phase of a monitored circuit and a D or C-class grounding electrode or a ground structure etc. of an electrical equipment connected to the grounding electrode, execute a phase judgment of a leakage current detected by a zero-phase current transformer on the basis of the monitored voltage, and stop an output operation of the leakage detector when the leakage current is a suffered current flowing from a load side L of the detecting zero-phase current transformer toward the power side K, i.e. the transformer and when the circuit wire-to-ground voltage exceeds an appropriately-established dynamic sensitivity voltage value.

Abstract: An electric power converter includes a cooler and an electronic circuit. The cooler includes a heat sink, a cooling fan, and a wind tunnel. A plurality of radiator fins are provided on a heat-sink base in the heat sink. The cooling fan is configured to feed cooling air through the plurality of radiator fins. The wind tunnel covers the plurality of radiator fins and the cooling fan. The electronic circuit includes a plurality of rectifiers and a plurality of input terminals. The plurality of rectifiers are provided on a side of the heat-sink base opposite to the plurality of radiator fins and are arranged side by side in a longitudinal direction of the heat-sink base. The plurality of input terminals are connected to the plurality of rectifiers with band-shaped conductors and are provided on a side of the plurality of rectifiers opposite to the heat sink.

Abstract: An electrical switching apparatus includes a plurality of poles each having a Rogowski coil and a conductor passing through an opening thereof, and a processor circuit including a sensor circuit including a plurality of inputs each electrically interconnected with an output of the Rogowski coil of a corresponding pole. The sensor circuit further includes a number of outputs having values each corresponding to current flowing through the conductor, a memory including for each corresponding pole an offset value and a gain correction factor for the sensor circuit, and a gain correction factor for the Rogowski coil, a number of routines, and a processor cooperating with the sensor circuit and the routines to provide for each pole a corrected current value as a function of a corresponding one of the values, the sensor circuit offset value and gain correction factor, and the Rogowski coil gain correction factor.

Abstract: An electrical switching apparatus includes a number of separable contacts, an operating mechanism structured to open and close the separable contacts, a number of sensors structured to sense at least current flowing through the separable contacts, and a processor structured to cooperate with the operating mechanism to open and close the separable contacts. The processor determines a fault from the sensed current flowing through the separable contacts. The processor further responsively opens the separable contacts if the sensed current associated with the fault is less than the interrupting rating of the electrical switching apparatus. The processor keeps the separable contacts closed and waits for another circuit interrupter to interrupt the fault if the sensed current associated with the fault is greater than the interrupting rating.

Abstract: An electrical switching apparatus includes a number of separable contacts, an operating mechanism structured to open and close the separable contacts, a number of sensors structured to sense at least current flowing through the separable contacts, and a processor structured to cooperate with the operating mechanism to open and close the separable contacts. The processor determines a fault from the sensed current flowing through the separable contacts. The processor further responsively opens the separable contacts if the sensed current associated with the fault is less than the interrupting rating of the electrical switching apparatus. The processor keeps the separable contacts closed and waits for another circuit interrupter to interrupt the fault if the sensed current associated with the fault is greater than the interrupting rating.

Abstract: An intrinsically safe energy limited circuit for space-restricted applications includes a fuse and resistor in series with a protected circuit or component wherein the fuse dissipates most of the power when the protected circuit or component is short circuited.

Abstract: A connector system includes a circuit board having a plurality of holes extending therethrough. First and second connector bodies, each having a front wall, are positioned on first and second sides of the circuit board, respectively. The front walls of the connector bodies have a plurality of signal pin openings aligned with the circuit board holes. A plurality of signal pins extend through the signal pin openings of the first and second connector bodies and through the circuit board holes. At least one of the plurality of circuit board holes has a diameter larger than a diameter of the signal pin extending therethrough, such that walls of the at least one circuit board hole are spaced apart from the signal pin extending therethrough.

Abstract: An audio compensation system (20) for producing a sound compensated output signal (So). The system comprises a volume control circuit (24) for producing a volume-adjusted signal (Sic) by applying a volume adjustment to an audio signal in response to a volume setting, wherein the sound compensated output signal is responsive to the volume-adjusted signal. The system also comprises circuitry (26, 30, 32) for producing an amplified signal (Sifa) by amplifying a selected bandwith of signals in response to the volume setting. The sound compensated output signal is also responsive to the amplified signal.

Abstract: A static excitation system that can eliminate shaft vibrations of a generator and overvoltage when it is underexited is provided. The static excitation system includes an initial excitation equipment; a step-down transformer; a 3-phase diode bridge; a boost chopper provided with a transistor and a resister, and maintaining DC voltage to be constant; a DC chopper provided with a plurality of transistors and diodes, and supplying DC power to a rotor of a generator; a boost controller for controlling the boost chopper; and a DC chopper controller for controlling the DC chopper, wherein, overvoltage applied on the excitation system when underexcited is eliminated owing to the boost chopper preventing any changes at an output terminal of the generator from being transferred to the excitation system, and maintaining the excitation DC voltage to be constant; and also owing to the DC chopper which is capable of 4 quadrant operation, hereby pole slipping of the generator can be prevented.

Abstract: A temperature limiting device for connection across a common heater which senses the critical temperature of the heater to trip circuit breakers and thereby disrupt power to the heater when the critical temperature exceeds a predetermined value. The device includes an SCR or triac connected across power lines to the heater and which is triggered by a comparator monitoring the output of an integrator circuit. The input to integrator circuit is connected to the output of a thermocouple device. Upon the critical temperature of the heater exceeding the predetermined value as determined by the integrator and comparator circuits the SCR or triac is fired so as to short the voltage lines and thereby open the mechanically resettable circuit breakers.

Abstract: A ground fault interrupter type device for protecting an electrical load device such as a range which has conductors supplied from a power source including overcurrent interruption means for interrupting the power source when a predetermined current threshold is exceeded. The electrical load device is subject to a first class of failure characterized by excessive current flow between at least one of the conductors and a ground reference point, with circuit current remaining at or below the predetermined current threshold; and to a second class of failure characterized by current through at least one of the conductors being above the predetermined current threshold. Failures of the second class include ground fault failures. In order to reduce the current interruption capability requirement for the ground fault interrupter device, there is included a means for preventing conductor interruption thereby in the event a failure of the second class occurs.

Abstract: A thyristor pulse control circuit has a main thyristor, a commutation circuit including a commutating capacitor, and a bypass contactor connected across the main thyristor, and is provided with apparatus for applying a gating signal to the main thyristor immediately before the contacts of the bypass contactor close and also immediately before the contacts of the bypass contactor close to prevent arcing at the contacts. The application of the gating signal is inhibited if a comparison of the voltage across the commutating capacitor with the load current flowing immediately before the bypass contactor closes indicates that the load current is too great to be safely commutated by the commutating capacitor at the measured voltage.

Abstract: A self-powered solid state overload relay circuit having current transformers energized by conductors supplying current to a multiphase alternating current motor. The transformers have secondary windings connected to charge a capacitor with a voltage indicative of the magnitude of the maximum current in the motor windings. The circuit includes presetable impedance circuits which permit the circuit to be easily programmed to respond to a range of abnormal motor currents in the winding in motors of varying size and service factor ratings, components which are arranged to duplicate the operation of melting alloy and bimetal type overload relays in an automatic or in a trip-free manual reset mode, a light emitting device which visually indicates when the relay is in a tripped state, and components which cause the relay to be insensitive to ambient temperature variations.