72results about How to "Improve current limiting performance" patented technology

Conductive polymer current-limiting fuses. when connected in series with conventional mechanical circuit breakers, exhibit extremely low let-through values. Particularly, conductive polymer current-limiting fuses based on conductive elastomeric material are disclosed which exhibit extremely low let-through values, namely less than 5,000 A2s with a switch current of 1.79 kAp, preferably less than 2,500 A2s, most preferably no more than 2,250 A2s.

To provide a current limiting circuit breaker capable of achieving downsizing and cost reduction of a device while improving current limiting performance. The current limiting breaker is provided with a first and a second mechanical switch (10, 10) connected in series, a first diode (11), a first snubber circuit (12), and a first current limiting impedance (13) which are mutually connected in parallel between both ends of the first mechanical switch, and a second diode (11), a second snubber circuit (12), and a second current limiting impedance (13) which are mutually connected in parallel between the both ends of the second mechanical switch. The anodes of the first and the second diodes are connected to each other and connected to the connection point of the first and the second mechanical switches.

The invention relates to a breaker with a forced flash barrier device. The breaker comprises a shell, a movable contact and a fixed contact, wherein the shell is internally provided with a lever made of an insulating material and composed of a left moment arm, a right moment arm and a fulcrum, the left moment arm of the lever is inserted into a gap between the movable contact and the fixed contact since the right moment arm is pushed rightwards by the movable contact during the separation process of the movable contact and the fixed contact, and the left moment arm of the lever goes out of the gap between the movable contact and the fixed contact since the left moment arm is pushed leftwards by the movable contact during the closing process of the movable contact and the fixed contact. The breaker is simple in structure and reliable in movement, can quickly cut off an electric arc when the movable contact and the fixed contact are separated so as to improve arc voltage, increase the breaking capacity and the current-limiting capacity of the breaker, widen the application range of the breaker and realize reversible protection.

The invention discloses a flow restricting ring, which is simple in structure, good in flow restricting effect and can be adjustable. The flow restricting ring comprises a ring body (1), a flow restricting pillar (2), a ring-shaped bracket (3) sleeved in the ring body (1) and fixedly connected with the flow restricting pillar (2), and a flow restricting rubber ring (4) sleeved on the flow restricting pillar (2), wherein a flow restricting hole (5) is formed between the flow restricting pillar (2) and the ring-shaped bracket (3); an overflow groove (6) is formed at the circumference of the flow restricting pillar (4); an adjusting ring (7) is coaxially arranged above the ring-shaped bracket (3); a plurality of adjusting grooves (8) are formed at the circumference of the ring-shaped bracket (3); and adjusting bulges (9) matched with the adjusting grooves (8) are arranged at the circumference of the adjusting ring (7). The flow restricting ring can be applied to the technical field of wall-mounted furnaces, water heaters and other pipeline equipment.

The invention belongs to low-voltage electrical equipment, and relates to a rotating shaft clamping mechanism in a low-voltage circuit breaker. The rotating shaft clamping mechanism comprises a rotating shaft body and a moving contact terminal, wherein the moving contact terminal horizontally passes through an inner chamber of the rotating shaft body, can rotate around the centre of the rotating shaft body and is symmetrical about the centre; the front and rear ends of the moving contact terminal are provided with moving contacts corresponding to an upper fixed contact and a lower fixed contact on the circuit breaker respectively; the front and rear parts of the symmetrical centre of the moving contact terminal are fixed with a clamping pin extended out of the two sides respectively; the two ends of each clamping pin are towed by a pair of tension springs positioned outside the rotating shaft body; the fixed end of each tension spring is connected to corresponding fixed pins on the two outer sides of the rotating shaft body; the upper and lower edges of the rotating shaft body are provided with a section of cam surface respectively; each cam surface consists of two sunken sections and an arched section; the two sunken sections are positioned at the two ends of the cam surface, while the arched section is positioned on the middle part of the cam surface; and the clamping pins always cling to and are pressed on the corresponding cam surfaces under the action of the tension springs and can stay at the bottoms of the corresponding sunken sections. The rotating shaft clamping mechanism has the characteristics of simple structure, reliable motion and convenient manufacturing and mounting.

Provided is a fault protection applied to a wind power plant and an energy stabilization circuit. A power converter is composed of a voltage source converter and a chopper or a current source converter. A direct current end of a rectifier is connected with a switch provided with an antiparallel diode and a buffer absorption circuit in parallel. A primary side of a single-phase transformer is connected with a switch and a resistor in parallel, and a secondary side of the single-phase transformer is connected with an alternative current output end of the rectifier. The primary side of the single-phase transformer is respectively connected with a power grid and a switching-in end of the wind power plant. A three-phase alternative current end of a power converter is connected with the power grid and a switching-in end of the wind power plant through a three-phase filter circuit and a three-phase transformer. A direct current end of the power converter is connected with a direct current end of the rectifier in series and then connected with an energy storage inductor in series. Under a normal condition, power output of the wind power plant is smoothed through charging and discharging of the energy storage inductor. Under a fault condition, the energy storage inductor is firstly utilized to limit current, then a thyristor of the rectifier is turned off, and the energy storage inductor is disengaged from the power grid. Current is limited through the resistor connected with the primary side of the transformer in parallel.

The invention belongs to low voltage electrical equipment, relating to a contactor falling-resistant device in a low-voltage circuit breaker. The contactor falling-resistant device comprises a spindle body and a moving contact, wherein the moving contact penetrates through the inner cavity of the spindle body from front to back and can rotate around the center of the spindle body; the moving contact is in central symmetry, the front and rear ends of the moving contact are respectively provided with a moving contact point which corresponds to fixed contact points at the upper and lower parts of the circuit breaker; the front and rear part of the centre of symmetry of the moving contact are respectively provided with a chute; each chute is internally provided with a bayonet lock which stretches out of the two sides; two ends of each bayonet lock are dragged by a pair of tension springs positioned outside the spindle body; the fixing ends of the tension springs are connected to fixing pins at two external sides of the spindle body; the upper and lower edges of the spindle body are respectively provided with a section of camming surface which is composed of two hollow sections at two ends and a hunch-up section in the middle; and the bayonet lock is always pressed on the camming surfaces under the action of the tension springs and can stay at the bottoms of the two hollow sections. The invention has simple structure and reliable action and is convenient to manufacture and install.

The related discharge-form current limiter for short fault is formed by paralleling an auxiliary inductance and a discharge tube on current device. The production can not only automatic limit fault current peak, but also limits the rise rate and stable value at any time without any control circuit. This invention reduces cost and improves power network reliability and security.

The invention discloses a self-saturation electric reactor type fault current limiter. The self-saturation electric reactor type fault current limiter comprises a first branch circuit, a second branch circuit and an electric reactor Lc, wherein the first branch circuit and the second branch circuit are connected in parallel, and the electric reactor Lc is connected with the first branch circuit and the second branch circuit in series. The first branch circuit comprises a current limiting protection electric reactor Lb2, a self-saturation electric reactor Lsat and a recovery time current dropping resistor Rj, wherein the current limiting protection electric reactor Lb2, the self-saturation electric reactor Lsat and the recovery time current dropping resistor Rj are sequentially connected in series. The self-saturation electric reactor comprises an iron core and two winding coils. The self-saturation electric reactor type fault current limiter is simple in circuit structure, and has the advantages of being significant in current limiting effect, suitable for wider-range input voltages, reliable, stable, high in practicability and the like.

A reactor-type short circuit fault current limiter, comprising a first reactor (L1), a second reactor (L2), a switch (K1), a capacitor (C1) and arresters (H1, H2 and H3). The first reactor (L1) consists of a first winding (L11) and a second winding (L12) by intercoupling through a magnetic circuit, one end of the first winding (L11) and one end of the second winding (L12) are connected in parallel to each other at a first connection point (a), and the other end of the first winding (L11) is connected in series to the switch (K1) and then connected in parallel to the other end of the second winding (L12) at a second connection point (b). When the power grid is in a steady state, a current limiter works in a series resonance or series compensation state, and presents a low impedance; when the power grid has a short circuit fault, the windings of a reactor undergo overcurrent saturation, and at the same time, the reactance change of the reactor is controlled by closing a switch, so as to produce a high impedance to achieve fault current limiting. The current limiter enhances the current limiting capacity, reduces the system manufacturing cost, has insignificant impact on the power grid, and improves the operational safety and reliability of the power grid.

The invention discloses a current limiting method of a transformer current limiting device based on manual zero-crossing current limiting. When a short circuit fault occurs, a controller immediately sends a switching-off instruction to a rapid vacuum circuit breaker after judging the short-circuit fault; when the rapid vacuum circuit breaker is switched off and the distance between contacts reaches a rated opening distance, the controller switches on a controllable discharge gap Spark2; a capacitor C2 and an inductor L2 are connected in series for resonance so as to generate reverse high-frequency current equivalent to the instantaneous amplitude of the short-circuit current and superpose the reverse high-frequency current on a rapid vacuum circuit breaker loop; the quick vacuum circuit breaker completes short-circuit current switching-on and switching-off; then, the short-circuit current is transferred to a ZnO branch of a zinc oxide arrester and the capacitor C2 is charged; when thevoltage of the capacitor C2 tends to be stable and reaches the residual voltage of the zinc oxide arrester ZnO, the zinc oxide arrester ZnO is switched on, the controllable discharge gap Spark2 is switched off, then the zinc oxide arrester ZnO continuously absorbs short-circuit current energy, and the zinc oxide arrester ZnO is switched off when the current crosses zero.

The invention discloses an LDO multi-integrated protection circuit. The LDO multi-integrated protection circuit connected with a basic LDO circuit comprises an input power VDD detection module, a temperature detection module, a current detection module and a protection module integrated and connected. The input power VDD detection module outputs a current Is1, the current detection module outputsa current Is2 corresponding to the basic LDO circuit, the temperature detection module outputs a current Iptc, output currents of the above three modules are connected to an adder, and the protectionmodule is connected among output currents of the detection modules, an input power supply VDD and a grating of a power tube Mp of the basic LDO circuit to realize current limiting protection for the basic LDO circuit. Design of a multi-integrated protection circuit is used, a PTC current generation circuit is introduced, current detection, temperature detection and input voltage detection are fused into integrated LDO protection, the current limiting performance of the LDO is improved reliably, and recovery time of self output IL is shortened.

The invention discloses a subminiature molded case circuit breaker, which comprises a bottom shell, a moving contact mechanism, a fixed contact, an arc extinguishing chamber and a traction rod. The subminiature molded case circuit breaker is characterized in that the traction rod, a traction rod bracket and an armature of a traditional molded case circuit breaker are integrally laminated into an integral structure, so that the size is reduced; a moving contact, the fixed contact and the arc extinguishing chamber of the subminiature molded case circuit breaker within the finite volume can be lengthened; the current limiting capacity of the molded case circuit breaker is improved; the breaking capacity of the subminiature molded case circuit breaker reaches the breaking level of the similar molded case circuit breaker; the working performance is more stable and reliable than that of a miniature circuit breaker while the size is greatly reduced; the subminiature molded case circuit breaker can be arranged on a guide rail for use like the miniature circuit breaker; and the subminiature molded case circuit breaker can be widely applied to building electricity.