A kind of no-spark safety switch, socket and safe power on/off method
Technical field
The present invention relates to a kind of safety switch, specifically, be a kind of when carrying out switching manipulation the safety switch of no-spark, no impingement, the invention still further relates to the socket that comprises this safety switch and the method for safe power on/off.
Background technology
Load such as industrial equipment, household electrical appliance all presents certain perception and capacitive, in the connection process of load and power supply, load capacity moment energising when circuit is connected, electric capacity never electricity is short more to the process time that is full of electricity, the inductive kick electric current is strong more, tends to arcing and produces spark; The interrupting process of load and power supply, inductive load instant cut-off when circuit disconnects, inductance is short more to the process time of outage from big electric current, and inductive surge is strong more, also can arcing produce spark.The contact contact-making surface of switch contact or plug and socket does not recline, and loose contact also can produce spark when folding and charged plug.These sparks are dangerous, and especially in inflammable and explosive place, the spark that need avoid Switching Power Supply to cause causes danger such as blast.
Existing sealed type safety anti-explosive socket and safety anti-explosive switchgear are to prevent to explode with contacting of contact electric arc by sealing isolated combustible, and this mode still exists electric arc and spark in the seal internal electrical contact, has potential hazard.For example damage is arranged, when slot leakage is arranged, also can cause danger when seal casinghousing.
Major defect and deficiency that prior art exists have:
1, can't stop to produce electric arc when load inserts power supply or withdraws from power supply fully, spark causes burning or explosion accident;
2, switch contact and plugs and sockets are burnt damage by electric arc, reduce the functional reliability and the useful life of device for switching;
3, drop into condensive load equipment and can produce over-current shock;
4, excision inductive load equipment can produce the overvoltage impact;
The Danger Electric shock risk accident takes place when 5, load inserts power supply or withdraws from power supply easily.
Summary of the invention
The technical problem to be solved in the present invention can not produce safety switch, socket and the safe power on/off method of spark when providing a kind of power on/off.
In order to solve the problems of the technologies described above, the invention provides a kind of safety switch, the switch triggering circuit and the switching transistor that comprise electric connection, described switching transistor is serially connected on the power line, described switch triggering circuit is used to export triggering signal and gives described switching transistor, transistorized disconnection of control switch and conducting, described power line two ends are respectively applied for and connect power supply and load.
Further, also comprise a rectification circuit, the input termination power of described rectification circuit, the described switch triggering circuit of output termination is used to described switch triggering circuit that working power is provided.
Further, described rectification circuit is made up of the dividing potential drop capacitance resistance, rectifier diode, voltage-stabiliser tube and the filter capacitor that electrically connect successively.
Further, described switching transistor is by a pair of antiparallel thyristor, and the protection diode of thyristor two ends parallel connection and resistance composition.
Further, described switch triggering circuit is made up of the current-limiting resistance, infrared reflection optocoupler, the zero cross fired bidirectional triode thyristor optocoupler that electrically connect successively, exports triggering signal by described zero cross fired bidirectional triode thyristor optocoupler to described switching transistor.
Further, also be serially connected with buffer circuit on the power line between described switching transistor and the load.
Further, described buffer circuit is made up of ground capacity, resistance, and described electric capacity, resistance parallel connection are connected between power firestreak and the ground wire.
The present invention also provides a kind of socket that comprises above-mentioned safety switch.
The present invention also provides a kind of method that realizes safe power on/off, comprising:
Switching transistor is inserted between power supply and the load with off-state;
Receive energized instruction by a switch triggering circuit, and the output triggering signal is given described switching transistor when the supply voltage zero passage;
Described switching transistor receives conducting after the described triggering signal, and the path between power supply and the load is connected.
Further, behind the path between energized and the load, also comprise:
The switch triggering circuit receives deenergization instruction, stops exporting to the triggering signal of described switching transistor;
Described switching transistor turn-offs behind current over-zero, and the path between power supply and the load is disconnected.
Contactless fully in the safety switch circuit of the present invention, the arcing phenomenon can not occur: not charged during socket when plug inserts, load capacitance voltage is zero, not sudden change, and non-inductive electric current can arcing not produce spark; Automatically cut off the electricity supply at load current point before plug is extracted, the load inductance electric current is zero, not sudden change, and non-inductive high pressure can arcing not produce spark yet.
Description of drawings
Fig. 1 is the embodiment that safety switch of the present invention is applied to single phase circuit;
Fig. 2 is the embodiment that safety switch of the present invention is applied to single phase circuit;
Fig. 3 is the circuit diagram of an embodiment of rectification circuit among the present invention;
Fig. 4 is the circuit diagram of an embodiment of switch triggering circuit among the present invention.
Embodiment
The invention will be further described below in conjunction with the drawings and specific embodiments, can be implemented so that those skilled in the art can better understand the present invention also, but illustrated embodiment is not as a limitation of the invention.
As shown in Figure 1, be applied to the embodiment of single phase circuit for safety switch of the present invention.This safety switch comprises the switch triggering circuit and the switching transistor of electric connection, and switching transistor is serially connected on the power line, and the power line two ends connect power supply and load respectively.Also comprise a rectification circuit, the input termination power of rectification circuit, output termination switch triggering circuit is used to described switch triggering circuit that dc supply is provided.
Wherein, rectification circuit can adopt half-bridge rectification circuit, full bridge rectifier etc., as shown in Figure 3, the rectification circuit in the present embodiment is made up of the dividing potential drop capacitor C 1, divider resistance R1, rectifier diode D1, D2, voltage-stabiliser tube D3 and the filter capacitor C2 that electrically connect successively.Switching transistor is made up of a pair of antiparallel thyristor, and that realizes power supply and load circuit cut-offs with closed thyristor two ends protection in parallel diode and resistance.Inverse parallel refers to two thyristor reverse parallel connections.Thyristor is conducting when triggering signal is arranged, power supply and load circuit closure; When Triggerless, turn-off after the thyristor current flows zero passage, power supply and load circuit disconnect.Thyristor herein can replace with other electronic power switch transistor devices.
As shown in Figure 4, the switch triggering circuit is made up of current-limiting resistance R2, the infrared reflection optocoupler U2 and the zero cross fired bidirectional triode thyristor optocoupler U1 that electrically connect successively in the present embodiment.During work, the switch triggering circuit detects physical switch state (open and close) and is converted to electric parameters by infrared reflection optocoupler U2, by the conducting of zero cross fired bidirectional triode thyristor optocoupler U1 output triggering signal control thyristor.Also available other triggering modes of circuits for triggering.
Also be serially connected with buffer circuit on the power line between switching transistor and the load, buffer circuit is made up of ground capacity and resistance, and described electric capacity, resistance parallel connection are connected between power firestreak and the ground wire.Buffer circuit is eliminated electronic switching device and is closed the have no progeny induced voltage of still existence and the influence of leakage current, guarantees that thyristor disconnects back loading and power supply disconnects fully.
In the present embodiment, only be serially connected with switching transistor on live wire, in other embodiments, also can be connected in series switching transistor simultaneously on live wire and zero line, the switching transistor on live wire and the zero line is subjected to the Synchronization Control of switch triggering circuit.
As shown in Figure 2, when safety switch of the present invention is applied to three-phase circuit, all be serially connected with switching transistor on three live wires, each switching transistor is subjected to the Synchronization Control of switch triggering circuit, and rectification circuit can be from power taking on any live wire and the zero line.
The method of the safe power on/off of realization of the present invention may further comprise the steps:
Switching transistor is inserted between power supply and the load with off-state;
Receive energized instruction by a switch triggering circuit, and the output triggering signal is given described switching transistor when the supply voltage zero passage;
Described switching transistor receives conducting after the described triggering signal, and the path between power supply and the load is connected.
Behind the path between energized and the load, also can may further comprise the steps:
The switch triggering circuit receives deenergization instruction, stops exporting to the triggering signal of described switching transistor;
Described switching transistor turn-offs behind current over-zero, and the path between power supply and the load is disconnected.
Safety switch of the present invention is safer, simple, convenient than traditional product when operation.Plug inserts or extracts is complete operation, and operation all is to carry out under off-position, electric shock accidents can not take place.Traditional product is hot line job when inserting or extracting, so keep away unavoidable grafting and the starting the arc, arcing phenomenon when extracting.Part adopts the product of electromagnetic relay, and the contact also can produce spark phenomenon when the adhesive of relay and disconnection.The present invention is not charged fully in the process of plug plug, and contactor partly adopts complete contactless method, so can not produce pyrophoric behavio(u)r.Power consumption equipment all has certain electric capacity and inductance, and traditional product the time causes the electric capacity of load and the voltage or the current break of inductance in plug, and output surge voltage and electric current influence useful life of equipment, the serious device damage that causes.The present invention is an off-position when the plug plug, contactor process electric current and voltage smooth change, and electric current cuts off at zero crossing, and load can not produce the surge voltage electric current.The switch triggering circuit work power is obtained by power supply is carried out the dividing potential drop rectifying and wave-filtering among the present invention, need not external control power supply.The present invention's electrically contacting property in use is quite reliable, can not cause that control system is malfunctioning because of loose contact, communication system is interrupted, image is lost, transmitted to computer error code and file and distorted signals, appliance cut-off etc.Also can effectively prevent simultaneously the contact portion superheating phenomenon that causes because of loose contact.
The above embodiment is the preferred embodiment that proves absolutely that the present invention lifts, and protection scope of the present invention is not limited thereto.Being equal to that those skilled in the art are done on basis of the present invention substitutes or conversion, all within protection scope of the present invention.Protection scope of the present invention is as the criterion with claims.