Abstract:
The disclosed fault-current protective switchgear has an amplifier circuit (4) for generating a fault-voltage (UA) derived from a fault-current, a comparator circuit (10) for comparing the fault-voltage (UA) with a reference voltage (Uref), and a reference circuit (12) connected to a supply unit (15) for generating the reference voltage (Uref), as well as an operating voltage (UB) for the amplifier circuit (4). Means are provided which, when the output voltage (UN) of the supply unit (15) falls under a predetermined value (UZ), increase the reference voltage (Uref) at least up to the momentary operating voltage (UB') at least when the fault-voltage (UA) is smaller than the reference voltage (Uref).
Abstract:
The present invention relates to an overcurrent protection circuit for an electrical household appliance, said overcurrent protection circuit comprising an input stage operable to convert AC voltage to a DC voltage by which AC voltage is rectified and filtered, a voltage generator generating a peak voltage, a reference comparator having a programmable voltage reference (5) comparing said generated voltage with a reference voltage so as to be conducting when a certain voltage level is reached and an isolated signal output.
Abstract:
A circuit arrangement to provide electricity to electronic tripping devices, especially overload tripping devices for low voltage switching devices, comprising a current transformer device having an output voltage rectified and transmitted by a switching transformer supplied via series connection, comprising a load impedance, a diode, and a charging capacitor so that voltage in charging capacitor is reduced over a set limit and increased under a set limit by means of a comparator switching device. Switching transistor (TR) can be controlled by a comparator switch (KO) interacting with a differentiating device (DE), impulse generator device (IG) or pulse width modulator switching device (PW), thus avoiding incorrect assessment of current transformer (SW) d.c. load by means of targeted load function of charging capacitor (CL) which is series connected via load impedance (RB). Such circuit arrangements are used to control overload tripping devices.
Abstract:
Die Erfindung betrifft eine Anordnung zum Anlagen- und Personenschutz in mehrphasigen Niederspannungs-Versorgungseinrichtungen, welche von einer Störlichtbogen-Erfassungsei nheit auslösbar ist und Kurzschließer aufweist, welche zwischen den Sammelschienen der Versorgungseinrichtung einen Kurzschluss hersteilen, wobei die Kurzschließer jeweils durch eine elektronische Baugruppe mit Schaltelement angesteuert und aktiviert werden und hierfür die Störlichtbogen -Erfassungseinheit mit dem Eingang der elektronischen Baugruppe in Verbindung steht. Erfindu ngsgemäß ist zur Erhöhung der Kurzschlussstromfestigkeit eine Parallelschaltung von Kurzschlieiern vorgesehen. Zur sicheren Ansteuerung der parallel geschalteten Kurzschließer ist eine Energiespeichereinheit zwischen den Phasen der Niederspannungs-Versorgungseinrichtung angeschlossen, weiche auf einen Regler zur Bereitstellung der Ansteuerspannung für das Schaltelement führt, so dass auch im Fall eines zeitlich ungleichen Ansprechens der parallel geschalteten Kurzschließer mit resultierendem Verlust der Versorgungsspannung das Schaltelement für den langsameren der Kurzschließer aktivierbar ist.
Abstract:
A self-powered multiple phase circuit protection device including a plurality of current transformers connected in parallel with each other and associated with one phase of a multiple phase load for providing signals representative of the current flowing in an associated phase. A switch can be actuated to interrupt power to the multiple phase load, and a fault determining circuit is connected to the circuit transformers and to the switch for actuating the switch during at least one predetermined condition of the current signals. The fault determining circuit has digital pulse extender circuitry for converting the current signals into DC signals, and a digital timer for delaying actuation of the switch.
Abstract:
In the case of a residual current device (1) having a test circuit (2) for production of a fault test current, which test circuit (2) has at least one first test resistor (3) and a test button (4), it is proposed for accurate checking of the serviceability, in particular independently of the mains voltage, that the test circuit (2) has a control circuit (5), and that the control circuit (5) be designed such that a fault test current which is produced by the test circuit (2) - essentially independently of the applied voltage from an electrical mains system to be protected - has a predetermined and essentially constant value.
Abstract:
Bei einem Fehlerstromschutzschalter (1), mit einem Prüfstromkreis (2) zum Erzeugen eines Prüffehlerstroms, welcher Prüfstromkreis (2) wenigstens einen ersten Prüfwiderstand (3) sowie einen Prüftaster (4) aufweist, wird zur genauen, insbesondere netzspannungsunabhängigen, Überprüfung der Funktionssicherheit vorgeschlagen, dass der Prüfstromkreis (2) einen Regelstromkreis (5) aufweist, und dass der Regelstromkreis (5) derart ausgebildet ist, dass ein durch den Prüfstromkreis (2) erzeugter Prüffehlerstrom − im Wesentlichen unabhängig von der anliegenden Spannung eines zu schützenden elektrischen Netzes − einen vorbestimmten und im Wesentlichen konstanten Wert aufweist.
Abstract:
The invention relates to a circuit arrangement to provide electronic tripping devices with electricity from a current transformer (SW). A switched-mode power supply unit (SNT), especially a reactance step up transformer(DR) with a pulse-width voltage control, is located downstream from the charging capacitor (CL). When set value (UA) is reached for output current at an output capacitor (CA) only a very high pulse duty factor is provided. Maximum power point control is provided in the initial phase of charging. Such circuit arrangements are used to provide an electricity supply for low and medium voltage overload tripping devices.
Abstract:
The invention relates to an electronic tripping device power supply circuit arrangement especially for low or medium voltage over-current tripping devices. The current transformer comprises a voltage transformer (SPW) providing the tripping devices with a second auxiliary power supply (UH2) when current is lacking or relatively low current is present, and a voltage transformer (STW) providing the tripping devices with a first auxiliary power supply (UH1) when current is high. A second voltage transformer (SR2) to produce the second auxiliary power supply (UH2) is placed downstream from the voltage transformer (STW) and both auxiliary power supplies (UH1, UH2) are transmitted to a common auxiliary power supply connection (UH) by a diode decoupling device (DE). Such circuits are used to supply power to low and medium voltage over-current tripping devices.
Abstract:
For use in a trip unit, a switched current shunting arrangement in a circuit interruption tripping system couples the current transformers (A, B, C, G, F) to relatively low voltage and it accumulates a high level of energy quickly at power-up so that the tripping solenoid (128) can promptly be energized after the detection of a spurious fault condition. The arrangement regulates supply current from the current transformers to a trip voltage capacitor (78) and to a supply capacitor (20') at the input of a voltage regulation circuit. The current transformer charges the trip voltage capacitor to a first prescribed voltage level, and a current shunting circuit (142, 144) shunts current passing from the current transformer to the supply capacitor, such that during normal operation the supply capacitor is charged to a second prescribed voltage level, which is less than the first prescribed voltage level.