CN2777818Y

CN2777818Y - Self-restoring safety unit

Info

Publication number: CN2777818Y
Application number: CN 200520039935
Authority: CN
Inventors: 潘哲毅; 董显斌; 张一�
Original assignee: Delta Greentech China Co Ltd
Current assignee: Delta Greentech China Co Ltd
Priority date: 2005-03-03
Filing date: 2005-03-03
Publication date: 2006-05-03
Anticipated expiration: 2015-03-03

Abstract

The utility model provides a self-restoring safety unit, which is arranged between the side of a user and the side of an exchanger. The utility model comprises a recoverable fuse respectively connected in an external line circuit in series, a clamping device respectively connected with the recoverable fuse in parallel, and a discharge circuit respectively connected with an internal line circuit in parallel, wherein one end of the discharge circuit is grounded. The safety unit of the utility model can primely solves some defects existing in former safety units and has reliable effect on over voltage protection and over current protection. After the over voltage and the over current are eliminated, the safety unit can restore to normal state immediately, so the utility model can be repeatedly used for many times. The utility model primely solves the shortage of traditional disposable safety units and the defect of slow action reflection of recoverable safety units which are realized by mechanical manner.

Description

From the replica Security Unit

Technical field

The utility model relates to a kind of Security Unit, relates in particular to a kind of self-recovering type Security Unit of electronic type.

Background technology

Present normally a kind of disposable expendable Security Unit of the employed Security Unit of user, in the terminal block loop, be connected in series fuse, when outer line end has lasting overcurrent or overvoltage to take place, fuse failure in the Security Unit is avoided Security Unit and circuit catching fire at this moment, this Security Unit can not recover and scrap behind fuse failure, the Security Unit that needs the staff more to renew; A kind of half self-healing Security Unit of the employing that has, it adopts bimetallic spring shell fragment, when outside line has overcurrent or overvoltage to take place,, the discharge tube heating disconnects cut-off loop because of making the bimetallic shell fragment, thereby reach the purpose of protection, but it is slow that its shortcoming is a responsiveness, and consistency is poor, difficult control, when outside line had lasting overcurrent or overvoltage, the thermoelastic sector-meeting is action repeatedly constantly; The heat that the fault monitoring circuit of Security Unit normally adopts discharge tube to produce when action makes the fuse block fusing, and fuse block fusing back makes the warning circuit action by some mechanical devices, thereby reaches the fault warning function; Some Security Units that have utilize the fault current in the detection line to alarm; promptly be connected in series a resistance in to earth-return and come sampling voltage at protection circuit; when overvoltage or overcurrent appear in Security Unit; then there is pressure drop to produce on this resistance; reach the purpose of detecting fault by this pressure drop; though the resistance that should be connected in series is less, it has still influenced the effect of overvoltage or overcurrent protection.

Summary of the invention

Technical problem to be solved in the utility model provides a kind of from the replica Security Unit, and it has reliable over-voltage and over-current safeguard function, eliminates the back Security Unit at overcurrent-overvoltage and can return to normal state immediately, promptly can repeat repeatedly to use.

In order to solve the problems of the technologies described above, the utility model has adopted following technical proposals: provide a kind of from the replica Security Unit, be arranged between user side and the exchanger side, it comprises: be serially connected with the renewable type fuse in the outer line loop respectively; Be connected to the clamping device on the renewable type fuse respectively; The discharge circuit of line loop in being connected to respectively, an end ground connection of described discharge circuit.Further, should also connect an alarm circuit for detecting from the replica Security Unit.

Security Unit of the present utility model can solve the place of the some shortcomings in the former Security Unit well, has reliable over-voltage and over-current protection effect, eliminate the back Security Unit at overcurrent-overvoltage and can return to normal state immediately, promptly can repeat repeatedly to use the shortcoming that has solved the deficiency on traditional disposable Security Unit well and gone up slowly in the action reflection with the recovered Security Unit that mechanical system realizes.Simultaneously, being different from traditional way aspect the alarm detecting, has distinctive feature.

Description of drawings

Fig. 1 is the electrical block diagram of Security Unit;

Fig. 2 is the circuit theory diagrams of an embodiment of the Security Unit circuit of tape jam detecting;

Fig. 3 is the circuit theory diagrams of another embodiment of the Security Unit circuit of tape jam detecting.

Embodiment

Below in conjunction with circuit theory diagrams its operation principle is described in detail:

As shown in Figure 1: this Security Unit is to be used between user side and the exchanger side, plays the effect of protection switch.Because of there is the intrusion of thunderbolt and two kinds of harm of power-frequency voltage at user side, so just may between user and switch, add a Security Unit because of their damage that can cause switch that seals in for this reason, make switch avoid impaired by Security Unit.A line and b line in the circuit are outside lines, receive user side; A ' line and b ' line are interior lines, receive exchanger side.The resistance PTCR1 and the resistance PTCR2 that are connected between outside line and the interior lines are two resistance with positive temperature coefficient, clamping device PD1 and clamping device PD2 correspondence respectively are connected to resistance PTCR1 and resistance PTCR2, its effect is to guarantee that the ceiling voltage of resistance PTCR1 and two positive temperature coefficient resistors of resistance PTCR2 can not be higher than the clamping voltage of this device, and protective resistance PTCR1 and resistance PTCR2 avoid damaging because of overvoltage; Discharge tube VT1 and discharge tube VT2 are connected to ground after wherein an end joins, and the other end is received a ' interior lines and b ' interior lines respectively.

Under normal working condition, the resistance of resistance PTCR1 and resistance PTCR2 all is in low resistive state, and the signal transmission between switch and the user is unaffected, and each device in the circuit is not action all; Have under the unusual situation in outside line, promptly have thunderbolt or power-frequency voltage to seal in the circuit, then corresponding devices begins action in the circuit, has played the effect of protection.If the thunderbolt overvoltage is invaded, discharge tube VT1 or discharge tube VT2 move immediately and are short-circuit condition, and lightning strike signals is incorporated into the earth, and the voltage of circuit a ' line and b ' line is avoided overvoltage to damage by clamp thereby play the protection switch simultaneously.In lightning stroke process, because of resistance PTCR1 and resistance PTCR2 respectively and meet clamping device PD1 and PD2, the voltage at resistance PTCR1 and resistance PTCR2 two ends just is limited in a certain scope like this, thereby avoids resistance PTCR1 or resistance PTCR2 to damage because of overvoltage; If when overcurrent occurring in the circuit, because of the operating current of electric current above resistance PTCR1 or resistance PTCR2, then resistance PTCR1 or resistance PTCR2 are high resistant immediately, the electric current in the circuit are reduced to below its operating current, thereby have protected switch effectively; When having power-frequency voltage to invade in the circuit; it is by resistance PTCR1 or resistance PTCR2; and by discharge tube VT1 or VT2 clamp; when discharge tube VT1 or VT2 action; the electric current that flows through resistance PTCR1 or resistance PTCR2 this moment can surpass its operating current; then resistance PTCR1 or resistance PTCR2 are high resistant immediately; electric current in the circuit is reduced to below its operating current; play the effect of switch; thereby protect switch to avoid the power-frequency voltage infringement well; when resistance PTCR1 or resistance PTCR2 are high impedance; because of having only minimum electric current to flow through; therefore the temperature of each device can be not too high in the circuit, maintains the operating temperature of resistance PTCR1 or resistance PTCR2 usually, and Security Unit can bear power-frequency voltage for a long time and can not damage like this; after power-frequency voltage in the circuit disappears; resistance PTCR1 or resistance PTCR2 get back to normal temperature because of temperature reduces and become low resistive state, and Security Unit recovers automatically, need not change.

Be illustrated in figure 2 as a specific embodiment that has fault monitoring circuit from the replica Security Unit, because of the resistance PTCR1 in the circuit or resistance PTCR2 and discharge tube VT1 or the rising of VT2 action temperature, negative temperature coefficient resistance NTCR in the circuit makes temperature rise near these assemblies, its resistance raises with temperature and sharply descends, the current potential that g is ordered among the switching tube Q then rises, make the switching tube conducting, at this moment LED is luminous because of conducting, thereby reaches the function of fault warning.

Be illustrated in figure 3 as have fault monitoring circuit from another individual embodiment of replica Security Unit, because of resistance PTCR1 or resistance PTCR2 are high impedance when the action, then optocoupler U1 or U2 input have electric current to flow through, as long as the input conducting of an optocoupler is wherein arranged, then its also conducting of pairing output, at this moment LED conducting and luminous, thus reach the function of fault warning.

Claims

1, a kind of from the replica Security Unit, be arranged between user side and the exchanger side, and constitute outer line loop between the user side, constitute interior line loop, it is characterized in that, should comprise from the replica Security Unit: the renewable type fuse outside being serially connected with respectively in the line loop with exchanger side; The corresponding respectively clamping device that is connected on the renewable type fuse; Discharge circuit in being connected in the line loop, an end ground connection of this discharge circuit.

2, according to claim 1 from the replica Security Unit, it is characterized in that, described outer line loop is made of outside line (a) and outside line (b), described renewable type fuse is serially connected with the resistance that positive temperature coefficient is arranged (PTCR1) in (a) line for being respectively, be serially connected with the resistance with positive temperature coefficient (PTCR2) in the outside line (b).

3, according to claim 1 from the replica Security Unit, it is characterized in that, line loop is by interior lines (a ') and interior lines (b ') formation in described, described discharge circuit is made up of two discharge tubes (VT1, VT2), one end of described two discharge tubes is connected to interior lines (a ') and interior lines (b '), the equal ground connection of the other end.

4, according to claim 1ly it is characterized in that, should also be provided with an alarm circuit for detecting from the replica Security Unit from the replica Security Unit.

5, according to claim 4ly it is characterized in that from the replica Security Unit described circuit for detecting comprises: a negative temperature coefficient resister (NTC); One switching tube (Q); One light-emitting diode (LED); One end of the base stage connecting resistance (NTC) of described switching tube (Q), its collector electrode is by the other end of resistance (RC) connection electrical resistance (NTC), its emitter sending and receiving optical diode (LED).

6, according to claim 4 from the replica Security Unit, it is characterized in that, described circuit for detecting comprises: two optocouplers (U1, U2) that are connected with resistance (PTCR1), resistance (PTCR2) respectively, the output of described optocoupler (U1, U2) connects a light-emitting diode (LED).