40results about How to "To achieve the purpose of current limiting" patented technology

The invention relates to a linear regulator with a current limiting short circuit protection function. The linear regulator comprises a starting circuit, a reference voltage circuit, a current sampling circuit, a voltage sampling circuit, a comparison amplifier circuit, a short circuit protection circuit and a control tube V2, wherein the control tube V2 is connected between a direct current input end XB1 and a voltage regulation output end XB2; the starting circuit transmits an input voltage source into the reference voltage circuit; the reference voltage circuit provides regulated reference voltage for the comparison amplifier circuit to use; the output end of the control tube V2 is connected in series with the current sampling circuit; the current sampling circuit feeds a sampled output current signal back to the comparison amplifier circuit; the voltage sampling circuit feeds a sampled output voltage signal back to the comparison amplifier circuit; the comparison amplifier circuit processes the output current signal and the output voltage signal, and transmits the processed output current signal and the processed output voltage signal into the control end of the control tube V2, so that the control tube works in a linear region to fulfill the aim of current limiting voltage regulation; and the short circuit protection circuit processes the acquired output voltage signal by a photoelectric coupler B2, and transmits the processed output voltage signal into the control end of the control tube V2, so that the control tube V2 is regulated from the linear region to a switching-off region to fulfill the aim of short circuit protection.

The invention relates to the technical field of circuit breakers and particularly relates to a current-limiting structure and a circuit breaker. The current-limiting structure comprises a variable resistor assembly, wherein one end of the variable resistor assembly is suitable for being electrically connected with a heating element in the circuit breaker, and the other end of the variable resistor assembly is electrically connected with a moving contact in the circuit breaker to be connected in series in a main loop of the circuit breaker; one end of the linkage mechanism is in linkage connection with the variable resistor assembly, and the other end is in linkage connection with the moving contact; the variable resistor assembly has a first state in which the resistance value tends to zero when the moving contact is connected with a static contact in the circuit breaker, and a second state in which the resistance value is increased under the repulsion driving force of the moving contact and the static contact when the current of the main loop is too large; in the first state, the variable resistor assembly does not limit the current of the main loop; in the second state, the linkage mechanism and the moving contact are linked to provide driving force, and the variable resistor assembly limits the current of the main loop. The arc voltage is improved, and arc extinguishing is facilitated. The structure is advantaged in that the arc extinguishing capability is improved without increasing the size and the opening distance of the arc extinguishing chamber, and the size of the product is reduced.

The invention relates to the field of electric switches, and provides a liquid-stage metal current limiter. According to the liquid-stage metal current limiter, a first cavity is formed in a shell; liquid-state metal is contained in the first cavity; an electrode comprises a first electrode and a second electrode; both the first and second electrodes extend into the first cavity from the shell; aninsulating separation plate is arranged in the first cavity to divide the first cavity into a plurality of first sub-cavities; through holes are formed in the insulating separation plate; adjacent first sub-cavities are communicated through the through holes; and when the first and second electrodes are accessed to a normal circuit, current is formed between the first and second electrode and theinsulating separation plate forms a blocking effect for the current. When the circuit has short circuit fault, the liquid-stage metal current limiter can be converted from a low-impedance state to ahigh-impedance stage, so as to restrict short circuit fault current; and the reaction speed is high, and before the fault current reaches a first peak value, the short circuit current can be effectively restricted, so that electric equipment in the circuit is sufficiently protected and potential safety hazards are prevented.

The invention discloses an energy-saving discharge power supply of an electrical discharge machining machine, comprising an AC (alternative current) power supply, an alternative current-to-direct current voltage converter, a direct current-to-direct current voltage converter, a current-limiting unit, a time-limiting unit and a control unit. The invention can reduce the unnecessary waste of the power supply and achieve the purpose of energy saving.

The invention provides an over-current protection circuit of a three-way output DC / DC converter. Against the defects of existing over-current protection modes, a mode of directly detecting output load currents is adopted, the problem of drifting of over-current protection points is solved, detected output current signals are collected through a high-precision sampling resistor and then have access to an operational amplifier, over-current error signals are amplified and integrated through the operational amplifier, then control signals are output, and current-limiting protection of the circuit is achieved. Therefore, the control signals are produced after the operational amplifier regulates the over-current error signals, and the purposes of accurate current limit and stable control are achieved. The problem that a power switch tube is switched on and off frequently when a comparer is used is solved, the problem of the drifting of protection currents of a high end and a low end which are used for defecting an input switch current is solved, and the problem that the power switch tube which detects output currents through the resistor is switched on and off frequently and then is burnt up easily is also solved.

The invention discloses a series-connection current limiting circuit of a miner lamp intrinsic safety power supply. The series-connection current limiting circuit of the miner lamp intrinsic safety power supply is characterized by comprising a DC / DC (Direct Current / Direct Current) boosted circuit, a control circuit, a reference power supply, a current sampling circuit, a voltage sampling circuit and a three-stage series-connection power adjusting and protecting circuit, wherein the DC / DC boosted circuit is formed by an IC1 (Integrated Circuit), diodes, capacitors and a resistor and is used for supplying a control power supply; the control circuit is formed by an IC2 and resistors and used for setting and comparing the voltage and the current; the reference power supply is formed by an IC3, a resistor and a capacitor and is used for supplying the preset control voltage for a '+' input end of the IC2; the current sampling circuit is formed by a resistor R1 and a resistor R2, and the voltage sampling circuit is formed by a resistor R12 and a resistor R13, and the current sampling circuit and the voltage sampling circuit are respectively used for supplying the preset control voltage for a '-' input end of the IC2; and the three-stage series-connection power adjusting and protecting circuit is formed by an FET2 (Field Effect Transistor), an FET3 and an FET4. According to the series-connection current limiting circuit of the miner lamp intrinsic safety power supply, disclosed by the invention, the current limiting circuit is formed by applying power semiconductor devices and other electronic devices, and the situations that when in normal work, the inner resistances of the devices are kept to the lowest, and no influence on the working performance of loads is realized; and the inner resistances of the devices can be increased immediately when the loads are in over current or short circuit failure, the failure current can be immediately limited within the safety current, and thus the miner lamp power supply can be safely protected.

The embodiment of the present application discloses a method, device and device for current limiting based on a token leaky bucket. The current limiting threshold of the leaky bucket is the token insertion rate of the token leaky bucket, and the token leaky bucket is used to control the access request flow of the application in the monitored device not to exceed the current limiting threshold; if the monitored The relationship between the first performance index and the threshold value of the first performance index in the performance index of the device satisfies the current limiting threshold adjustment condition, then according to the current limiting threshold value of the token leaky bucket, adjust the condition according to the current limiting threshold value The corresponding current-limit threshold adjustment method adjusts the current-limit threshold of the token leaky bucket.

The invention discloses a novel excavator current-limiting control system, belonging to the field of electrohydraulic control of hydraulic excavators. The novel excavator current-limiting control system comprises a master controller, a main pump proportional valve, a getting-down pressure switch S2, a getting-on pressure switch S1, and a rotation speed sensor and further comprises a revolution pilot pressure sensor, a P1-pump outlet pressure sensor, a P1-pump current-limiting pressure sensor, a P2-pump current-limiting pressure sensor, a P2-pump maximum-flow control proportional valve and a P1-pump maximum-flow control proportional valve, which are respectively and electrically connected with the master controller. The novel excavator current-limiting control system has the beneficial effects that: the flexibility in model selection of hydraulic elements can be enhanced, meanwhile, a rotary motor and a travelling motor can be prevented from being damaged by overlarge flow of a hydraulic system; in addition, the actions in need of current limitation can be judged through a detection device so as to prevent 'one size fits all' type current limitation, the pump displacement of two single pumps can be limited through controlling the current of the two current-limitation proportional valves, closed-loop control is adopted for a current control loop of the proportional valves, and thus the accurate current-lamination control is realized.

The invention discloses a conveniently-connected structure of a highly-sealed liquid flow control ball valve. The conveniently-connected structure comprises a shell; a water passing groove is formed in the side wall of the shell, and a rotating groove is formed in the inner wall of the water passing groove; the inner wall of the rotating groove is slidably connected with a hollow ball, and circulating holes are formed in the inner walls of the two symmetrical ends of the ball correspondingly; and an air bag is glued to the inner wall of the upper side of the ball. The conveniently-connected structure has the advantages that through design of an air feeding rod and an air discharging rod, when the flow needs to be adjusted back again after excessive flow limiting, the air feeding rod and the air discharging rod can be simultaneously pressed, thus the air discharging rod drives a pushing block to extrude a connecting block, thus the connecting block drives an air discharging stop block to rotate, the inner wall environment of the air bag and the inner environment of an extrusion groove communicate, the air feeding rod drives an air feeding baffle to rotate, thus an air feeding groovecommunicates with the inner space of the extrusion groove, the air bag communicates with the outside environment, air in the air bag is released, thus the airbag is shrunk, the flow of a water flow is increased, and the flow of the water flow is adjusted.