CN87205714U

CN87205714U - Simple and easy non-arcing switch

Info

Publication number: CN87205714U
Application number: CN 87205714
Authority: CN
Inventors: 吕崇圭
Original assignee: Individual
Current assignee: Individual
Priority date: 1987-03-22
Filing date: 1987-03-22
Publication date: 1987-12-26

Abstract

The utility model provides a non-arcing switch device with contacts, in particular applied to a heavy task load circuit with that starts up frequently. The utility model is structured by parallel connecting the existing knife switch and the contacts of a contactor, etc. with a bypass flow link that comprises diodes and capacitors or controllable silicon. When the contacts are switched off, the current bypass via the bypass flow link and then is blocked. The utility model has the advantages of low cost, easy maintenance, simplicity, long service life, zero arc production while power is off, strong over-load ability and saving of a large amount of contact silver.

Description

Simple and easy non-arcing switch

The utility model relates to the contact switch device in order to control AC-DC Circuit break-make and conversion.

The existing contact switch that generally uses mainly comprises knife switch, automatic switch, change over switch, relay and contactor or the like, and a secondary or how secondary dynamic and static contact is arranged in their contact system.Under the effect of manpower, mechanical force or electromagnetic force, moving contact closes towards the fixed contact motion during work, and circuit is connected, otherwise circuit is cut off, and is bearing the task of connection, disconnection and change-over circuit.But, at the spark of the moment load current generation that contact cut-offs or strong electric arc, be easy to burn out contact, have an accident.Though, existing product has been taked the facility of remedying with silver contact and varied arc extinguishing, the electric arc that cuts off the power supply is still quite serious for the harm in contact life-span, and is more severe for the infringement of the big electric current important task of load affair switching device, the frequent lost of life of fault.

In order to address this problem, vacuum contactor and controllable silicon noncontacting switch have been arranged now, but, promoted difficulty because of costing an arm and a leg, keep in repair drawbacks limit such as complexity, overload capacity difference, rarely found on the market so far.

The purpose of this utility model provide a class simple and practical contact non electric-arc switch device arranged.

Basic implementation is: on the contact of existing various contact switches, in parallel one forms respectively by diode and capacitor etc., or the by-pass flow circuit link of forming by thyristor etc.Cut-off electric current that moment can produce electric arc originally through this link bypass at contact, and blocking-up rapidly in this link element, " with its ineffectual remedy, not as taking away the firewood under the cauldron " so fundamentally avoided the generation of contact electric arc and harm thereof just.

Be that example describes circuit structure of the present utility model and operation principle in detail with the embodiment shown in the Figure of description below:

Fig. 1 is the circuit theory diagrams (main circuit) of the simple and easy no electric arc D.C. contactor of embodiment capacitive bypass formula.Diode D and capacitor C are composed in series bypass link and main noddle on contactor CZ among the figure ₁Parallel connection, R is the auxilliary contact CZ of discharge resistance through this contactor ₂Link with capacitor C, E connects positive source, and L connects load.Load current is through CZ during work ₁By, at CZ ₁The moment of cut-offfing, former contact electric current was through D, C bypass, just through D C charged.The initial value of this electric current approximates former contact current value, sharply descends by index law subsequently, and moment (being advisable with 1～2 millisecond) is reduced to zero.So just reached both bypasses former contact electric current avoided the generation of electric arc, cut off the purpose of load current again rapidly.After the adhesive of following deuterzooid contactor, capacitor C is through R and CZ ₂Discharge is CZ once more ₁Disconnection performs by-pass flow and prepares.

The circuit that is made of diode and capacitors in series, for forward current charging conduction when the beginning, the characteristic of blocking behind full charge is the ultimata of this circuit.The optimum value of C capacitance size can be got 1～2 millisecond by formula: CV=It(t) estimation, also can select decision by experiment.

Fig. 2 is the circuit theory diagrams (main circuit) of the simple and easy no electric arc alternating current contactor of embodiment capacitive bypass formula, among the figure by diode D _1～4The bridge rectifier of forming, its AC side and main noddle on contactor CJ ₁Parallel connection, DC side and electrolytic capacitor C link, and X, L join with AC power and load respectively.CJ ₁During disconnection, no matter the direction of load current how, is all also blocked by capacitor C bypass through the gap bridge rectification, all the other situations are identical with Fig. 1 embodiment.

Fig. 3 is the circuit theory diagrams (main circuit) of the simple and easy no electric arc alternating current contactor of embodiment controllable silicon bypass type, the main contact CJ of the main circuit of bidirectional triode thyristor T and contactor among the figure ₁Parallel connection, its control utmost point is through an auxilliary contact CJ of this contactor ₂Deng linking with anode.Can use Machine Design and manufacturing means (for example suitably increasing and decreasing the distance of separation of each contact) to make CJ ₂Compare CJ ₁Connection shift to an earlier date constantly, fall behind (about 0.1～1 millisecond) during disconnection, also can make the two synchronous.This contactor adhesive whole load currents of when operation main contact CJ that flows through for a long time ₁, and just at CJ ₁Cut-off extremely short moment the internal burden electric current through controllable silicon T bypass, when the alternating current zero passage, turn-off immediately.Because in the each make and break process of this contactor, the ON time of controllable silicon T extremely lack (less than the alternating current half-wave), so the overload current of its rated current of permissible load more than 5 times during actual use.

Save element in order to simplify circuit, the utility model control blow-up, DC circuit can only be controlled a power line, and the control three-phase circuit can only be controlled two power lines, and remaining one can be closed the contact control that afterwards divides earlier with a pair.Use basic principle of the present utility model, can make simple and easy no arc type knife switch, classes such as simple and easy no arc type automatic switch, simple and easy no arc type change over switch, simple and easy no arc type contactor have contact non electric-arc switch electrical equipment.The utility model is particularly suitable for controlling high-power important task and is engaged in starting, changes frequent motor circuit and needs fire-proof and explosion-proof electric equipment.With existing contact switch and controllable silicon noncontacting switch relatively, the utility model has following advantage: simple in structure, overload capacity strong, the maintenance is easy, cheap.

When some need and change in the circuit that change over switch is arranged of circuit coupling method, use the utility model (for example changing in the circuit of motor steering and rotating speed when needed) or other on-load switch, can take the pre-converted switching circuit.The situation of the similar isolating switch of conversion on-off action of change over switch is carried out under currentless situation in this circuit, whole tasks of outage task or outage and connection, and all the on-load switch of being connected with change over switch by (or a plurality of) is finished.Wherein, the action of on-load switch constantly should according to above-mentioned requirements and change over switch work mechanically interlock or do the interlock of pull-in winding connecting and disconnecting of the circuit.

Fig. 4 is that embodiment controls the pre-converted non electric-arc switch device block diagram that double-speed motor is used.KA is simple and easy no arc type A.C. contactor among the figure, and 1HK is manual two-direction switch (three), and 2HK is manual double speed change over switch (two), and DSD is a two-speed motor.The contact KS of control KA pull-in winding connecting and disconnecting of the circuit ₁, KS ₂Be respectively the auxilliary contact of 1HK and 2HK, can use the means (for example changing the recessed position of cam) of mechanical aspects that they are disconnected in advance than main contact when disconnecting, when connecting, fall behind connection, make it to adapt to the requirement of the following course of work than main contact.Double-speed motor DSD prestart, this switching device KA, 1HK and KS ₁Disconnect, 2HK connects low-speed circuits, KS ₂Engage.During starting, its main contact of manual operation 1HK is connected earlier, afterwards KS ₁Connect, so KA adhesive motor low speed starting operation.During parking, its KS of manual operation 1HK ₁Disjunction in advance, KA has cut off the load current just disjunction of main contact of 1HK afterwards, and motor is in KA outage back stall.In like manner, change motor steering and change disconnection and ON Action in conversion (disconnect this road---connect that road) process of motor speed, all disconnect in advance and falls behind connection and match by KA at manual operation 2HK at manual operation 1HK.All finished by KA so switch on and off the task of load current, numerous contacts such as all the other 1HK, 2HK all move under the load current situation not having, so can greatly reduce their performance requirement.

The characteristics of pre-converted switch circuit devices mainly are to save the quantity of on-load switch, because on-load switch complex structure price is higher, so pre-converted switch circuit devices volume is little, cost is low, maintenance also is easier to.

Claims

1, all have the circuit switchgear of contact in order to the knife switch of control AC-DC Circuit break-make and conversion, automatic switch, change over switch, relay, contactor etc., the contact that this class device respectively has a pair or many pairs to switch on and off, it is characterized in that having in the contact system in the described same switching device pair or many secondary contacts in parallel with by-pass flow circuit link respectively, this by-pass flow circuit link or form by diode and capacitor etc., or form by ghyristor circuit.

2, switching device according to claim 1, it is characterized in that a, each bypass link be made up of diode bridge rectifier circuit and electrolytic capacitor etc., the AC side of this bridge rectifier is in parallel with the main contact of switching device, DC side and electrolytic capacitor link, and b, described bypass loop economize on electricity electrolysis condenser are connected through auxiliary contact and its discharge resistance.

3, switching device according to claim 1 is characterized in that of a, switching device is secondary or many secondary contacts are in parallel with the bidirectional triode thyristor main circuit respectively, and the control polar circuit of b, this bidirectional triode thyristor is connected with anode through an auxiliary contact etc.

4, switching device as claimed in claim 3 is characterized in that described bypass silicon controlled load current value, can be less than 1/5th of main circuit actual loading current value.

5, according to claim 2 or 3 described switching devices, it is characterized in that some contact in the same switching device, require than other contacts with making, or cut-off constantly backwardly a little, or connect the moment and shift to an earlier date a little in Machine Design.

When 6, needing and change the circuit that change over switch is arranged of circuit linking method, it is characterized in that described change over switch also is in series with on-load switch, disconnect moment preload switch at change over switch and disconnect in advance, or after change over switch was connected constantly, on-load switch falls behind to be connected.