CN201022145Y

CN201022145Y - Over current protection system for breaker

Info

Publication number: CN201022145Y
Application number: CNU2006201757753U
Authority: CN
Inventors: 黄章武; 高文乐; 佘定辉; 包志舟
Original assignee: PEOPLE ELECTRICAL APPLIANCES GROUP CO Ltd
Current assignee: Zhejiang People Electrical Appliance Co., Ltd.
Priority date: 2006-12-28
Filing date: 2006-12-28
Publication date: 2008-02-13
Anticipated expiration: 2016-12-28

Abstract

The utility model relates to an over current protective system of the breaker, comprising a singlechip circuit, a current mutual inductor, an A/D transformation circuit, a trip driving circuit and a trip executive unit, wherein a current detecting output end of the current mutual inductor is connected with a detecting signal input end of the singlechip circuit through the A/D transformation circuit; a trip controlling output end of the singlechip circuit is connected with the trip executive unit through the trip driving circuit; an alarm signal output end of the singlechip circuit is provided with an alarm circuit; and a function choosing input end of the singlechip circuit is equipped with an OFF choosing unit. The breaker of the utility model can satisfy the utilizing requirement of the special occasion, and insure that even if the fire pump is overloaded in the fire protection process, the utility model is unable to cause the fire pump to stop working and badly affect the emergent fire protection relief work.

Description

The over-current protection system of circuit breaker

Technical field

The utility model relates to a kind of over-current protection system of circuit breaker.

Background technology

The plastic casing of common moulded case circuit breaker is made up of base and cover, and all parts all are loaded among the plastic base.Circuit breaker has generally comprised functional units such as contact system, arc quenching system, operating mechanism and free tripping mechanism, over-current protection system, short circuit protection system and insulation crust, operating grip, the moving contact that operating mechanism is driven in the contact system by the handle transmission moves, make closing of power circuit breaker and disjunction, realize control electric wiring electric power energy stream; By sensing to electrical current heat and magnetic effect, to electric wiring transship, fault such as short circuit implements protection.

Circuit breaker is of many uses; it not only is used for the protection that backbone, branch road, circuit end etc. are made faults such as frequently not the closing of circuit (cable, electric wire) and electric equipment, branch and overload, short circuit, under voltage; also be applied to various loads, using separately and protecting as lighting loop, electric heating loop, motor circuit, silicon controlled rectifier loop, capacitor loops etc.

Chinese patent literature CN1076530 discloses a kind of intelligent controller of communicable plastics casing circuit breaker; comprise switching power circuit, voltage filter circuit, amplifying circuit and current filtering circuit, amplifying circuit, relatively testing circuit; the multicircuit switch circuit; the absolute value amplifying circuit, phase-locked loop frequency tracking circuit, detection circuit of power factor; leakage protection circuit; the dropout control circuit, single chip circuit, display keyboard circuit.Can the circuit parameter of three-phase and four-line independently be detected in real time; have and report to the police and defencive function; fault can permanent memory and inquiry, and presence states, setup parameter and failure logging can be sent to higher level's computer by communication interface, thereby forms the multilevel monitor system.

Chinese patent literature CN2629206 also discloses a kind of Based Intelligent Control type circuit breaker, and it is by various protections, demonstration and the controlled function of chip microcontroller circuit breaker.

Above-mentioned the deficiencies in the prior art part is: this circuit breaker can not satisfy the requirement of important fire-fighting equipment control with protection; do not meet in GB50054-95 " low-voltage distribution design specification " standard of the requirement of important fire-fighting equipment major loop with circuit breaker; promptly in the fire pump use,, appearance overload phenomenon has a strong impact on the carrying out of urgent fire control and disaster rescue even if can not making the fire pump outage.

The utility model content

The technical problem that the utility model solves provides the over-current protection system that a kind of energy satisfies the circuit breaker that important fire-fighting equipment is controlled.

In order to solve the problems of the technologies described above, the over-current protection system of circuit breaker of the present utility model comprises: single chip circuit, current transformer, A/D change-over circuit, dropout drive circuit and dropout performance element; The detection signal input of the current detecting output of current transformer order sheet machine circuit behind the A/D change-over circuit is for the current value in single chip circuit detection loop, circuit breaker place; The dropout control output end of single chip circuit links to each other with the dropout performance element through the dropout drive circuit, carries out the action of threading off to drive the dropout performance element; The alarm signal output ends of single chip circuit is provided with warning circuit; The function selecting input of single chip circuit is provided with the OFF selected cell, is used to set single chip circuit and is in first mode of operation or second mode of operation; When single chip circuit was in first mode of operation, the current value in the loop, circuit breaker place that single chip circuit records was during greater than pre-set threshold value, and single chip circuit only drives warning circuit and reports to the police, and carries out the action of threading off and do not drive the dropout performance element; When single chip circuit was in second mode of operation, the current value in the loop, circuit breaker place that single chip circuit records was during greater than pre-set threshold value, and single chip circuit drives warning circuit and reports to the police, and drove the dropout performance element and carry out the action of threading off.

In the technique scheme, also comprise and the two-way setting value input unit that is electrically connected of single chip circuit, be used for the threshold values that default single chip circuit is carried out the action of threading off.

In the technique scheme, the communication ends of single chip circuit is provided with serial communication interface, to communicate with independent communication units or host computer.

In the technique scheme, the off-line control input end of dropout drive circuit is provided with the off-line trip unit, to make the dropout performance element carry out the action of threading off in single chip circuit outage back by control dropout drive circuit.

In the technique scheme, the condition indicative signal output of single chip circuit is provided with status indicator lamp.

Compared with prior art, the utlity model has following good effect: the over-current protection system of (1) circuit breaker of the present utility model can make single chip circuit be in first or second mode of operation by the OFF selected cell.When being in first mode of operation, even if the current value in the loop, circuit breaker place that single chip circuit records is during greater than pre-set threshold value, single chip circuit only drives warning circuit and reports to the police, do not carry out the action of threading off and do not drive the dropout performance element, satisfied the instructions for use of special occasions, guaranteed in the fire-fighting process, even if fire pump overload can not make fire pump quit work yet and has a strong impact on urgent fire control and disaster rescue.And the selection by the OFF selected cell is set, and can make single chip circuit be in second mode of operation, so that circuit breaker plays normal protective effect, thereby has expanded the application surface of circuit breaker of the present utility model.(2) be provided with the off-line trip unit in the over-current protection system of circuit breaker of the present utility model, so that after single chip circuit outage the stopping control, the action of threading off is carried out in control, guarantees the Electrical Safety in loop, circuit breaker place.

Description of drawings

For the easier quilt of content of the present utility model is clearly understood, below the specific embodiment and in conjunction with the accompanying drawings of basis, the utility model is described in further detail, wherein

Fig. 1 is the circuit block diagram of the over-current protection system of circuit breaker of the present utility model.

Fig. 2 is current transformer in the over-current protection system of circuit breaker of the present utility model and A/D change-over circuit

The road schematic diagram.

Fig. 3 is single chip circuit, the dropout drive circuit, whole in the over-current protection system of circuit breaker of the present utility model

The circuit theory diagrams of definite value input unit, serial communication interface and OFF selected cell.

Embodiment

(embodiment 1)

See Fig. 1; the over-current protection system of the circuit breaker of present embodiment comprises: single chip circuit 100, current transformer 200, A/D change-over circuit 300, dropout drive circuit 400, dropout performance element 500, setting value input unit 600, serial communication interface 800, independent communication units or host computer 900, warning circuit 110, OFF selected cell 120, off-line trip unit 130 and status indicator lamp 140.

The over-current protection system of the circuit breaker of present embodiment is applicable to moulded case circuit breaker.Its operation principle is as follows:

When the circuit breaker of present embodiment is applied to the fire pump overload protection, then make single chip circuit 100 be in first mode of operation by OFF selected cell 120, the overload upper bound current value according to fire pump is provided with threshold values simultaneously.If the rated current of this fire pump is 1A, upper bound current value is 2A, and it is 2A that the overload-alarm threshold values then is set.When the current value in the loop, circuit breaker place that single chip circuit 100 records during greater than this threshold values, 100 of single chip circuits drive warning circuit 110 and report to the police, and carry out the action of threading off and do not drive dropout performance element 500.Until the fireman power supply of this fire pump is excised, or make single chip circuit 100 be in second mode of operation,, fire pump is quit work to carry out the action of threading off by OFF selected cell 120.When the overload current duration surpassed the fire pump ability to bear, the fire pump coil was promptly burnt.

When the circuit breaker of present embodiment is applied to the common electric machine overload protection, then make single chip circuit 100 be in second mode of operation by OFF selected cell 120, if the rated current of this motor is 0.5A, upper bound current value is 1A, it is 1A that the overload-alarm threshold values then is set.When the current value in the loop, circuit breaker place that single chip circuit 100 records during greater than this threshold values, single chip circuit 100 also drives dropout performance element 500 and carries out the action of threading off when driving warning circuit 110 and reporting to the police, and this motor is quit work.

The size of described threshold values should be determined according to the concrete load current value and the upper bound current value of each object of protection.

See Fig. 2, in the current transformer 200, connect the electric current mutual-inductance element that is arranged in the load major loop, to detect the size of current of 3 tunnel current i a, ib and ic by interface J1-J3.Rectifier bridge B4-B6, filter capacitor C7, C9, C10, C23-C25 and piezo-resistance CVS4-CVS6 form filter rectifier.34 pin of rectifier bridge B4-B6 are the current detecting output of current transformer 200.

Comprise 3 comparing unit U3A-U3C among the comparator module LM324 in the A/D change-over circuit 300, the termination in the same way of U3A-U3C is with reference to ground AGND, and the signal of telecommunication of 3 the 4 pin outputs of rectifier bridge B4-B6 is delivered to the backward end of U3A-U3C after step-down filtering; The output of U3A-U3C meets A0, A1 and the A2 of single-chip microcomputer U5 respectively, i.e. the detection signal input of single chip circuit 100.Earth connection behind 3 pin series diode D1, resistance R 100 and the voltage-stabiliser tube DZ100 of rectifier bridge B5.The contact of diode D1 and resistance R 100 is the first power end TEST.

See Fig. 3, the single-chip microcomputer U5 that adopts in the single chip circuit 100 is PIC16F877.The described first power end TEST of the power supply termination of dropout drive circuit 400, interface J6 links to each other with the control end of dropout performance element 500.The first power end TEST is through 1 pin of diode D12 rear port J6.2 pin of interface J6 connect the drain electrode of NMOS pipe, the source ground of NMOS pipe.The E0 end of single-chip microcomputer U5 is the dropout control output end, meets the grid IRF120 of NMOS pipe after this end serial connection diode D11 and the resistance R 45, and after the conducting of NMOS pipe, dropout performance element 500 is just carried out the action of threading off.Diode D13, voltage-stabiliser tube DZ21 and DZ22 shield.Capacitor C 34, resistance R 44 are used for voltage regulation filtering.

OFF selected cell 120 is button circuits, the regulator rectifier circuit that button circuit comprises comparing unit U3D among the comparator module LM324, be made up of diode D10, voltage-stabiliser tube DZ25 and capacitor C 25, button SW etc.The first power end TEST connects the backward end of U3D after resistance R 39, U3D holds 4 pin that meet U3A behind the series resistor R40 in the same way.When normal operation of circuit breaker, the SW that touches the button for the first time can make single chip circuit be in first mode of operation; The SW that touches the button for the second time can make single chip circuit be in second mode of operation.(in other embodiments, OFF selected cell 120 is can select to export high level and low level so that single chip circuit is in the switching circuit of first mode of operation and second mode of operation respectively.) status indicator lamp 140 is 3 LED that link to each other with the LED1-LED3 of single-chip microcomputer U5 end.

Link to each other with the display operating panel circuit by joint J4 in the setting value input unit 600.Warning circuit 110 is loudspeaker and drive circuit thereof, and the control input end of drive circuit connects the C1 end of single-chip microcomputer U5.(in other embodiments, also can be warning lamp and drive circuit thereof).Link to each other with the serial communication chip by joint J5 in the serial communication interface 800.

The detection signal input of the current detecting output of current transformer 200 order sheet machine circuit 100 behind A/D change-over circuit 300.The dropout control output end of single chip circuit 100 links to each other with dropout performance element 500 through dropout drive circuit 400.Setting value input unit 600 and single chip circuit 100 two-way electrical connections.The alarm signal output ends of warning circuit 110 order sheet machine circuits 100.The function selecting input of the output order sheet machine circuit 100 of OFF selected cell 120.

The communication ends of serial communication interface 800 order sheet machine circuits 100 is to communicate with independent communication units or host computer 900.

The control output end of off-line trip unit 130 connects the off-line control input end of dropout drive circuit 400.

The condition indicative signal output termination status indicator lamp 140 of single chip circuit 100.

The method of work of the over-current protection system of the circuit breaker of present embodiment comprises the steps:

A, setting value input unit 600 are carried out the threshold values of the action of threading off to single chip circuit 100 inputs; (if the circuit breaker of present embodiment is applied to the motor overload protection, the rated current of this motor is 1A, and the overload upper limit current is 3A; Then can set the threshold values of carrying out the action of threading off is 3A.)

B, single chip circuit 100 detect the current value in loop, circuit breaker place through A/D change-over circuit 300 summation current transformers 200;

C, when OFF selected cell 120 makes single chip circuit 100 be in first mode of operation, if the current value in the loop, circuit breaker place that records of single chip circuit 100 is during greater than described threshold values, 100 of single chip circuits drive warning circuit 110 and report to the police, and do not carry out the action of threading off and do not drive dropout performance element 500;

D, when OFF selected cell 120 makes single chip circuit 100 be in second mode of operation, if the current value in the loop, circuit breaker place that records of single chip circuit 100 is during greater than described threshold values, single chip circuit 100 drives warning circuit 110 and reports to the police, and drives the 500 execution dropout actions of dropout performance element through dropout drive circuit 400.

Single chip circuit 100 communicates through serial communication interface 800 and independent communication units or host computer 900, to carry out remote monitoring.When after single chip circuit 100 outages, off-line trip unit 130 makes dropout performance element 500 carry out the action of threading off by control dropout drive circuit 400.Single chip circuit 100 is by the current single chip circuit 100 residing mode of operations of status indicator lamp 140 indication, whether thread off action or be not in alarm condition of executed.

Claims

1. the over-current protection system of a circuit breaker comprises: single chip circuit (100), current transformer (200), A/D change-over circuit (300), dropout drive circuit (400) and dropout performance element (500); The detection signal input of the current detecting output of current transformer (200) order sheet machine circuit (100) behind A/D change-over circuit (300); The dropout control output end of single chip circuit (100) through dropout drive circuit (400) be used to drive dropout performance element (500) and carry out the dropout performance element (500) of the action of threading off and link to each other; It is characterized in that: the alarm signal output ends of single chip circuit (100) is provided with warning circuit (110); The function selecting input of single chip circuit (100) is provided with and is used to set the OFF selected cell (120) that single chip circuit (100) is in first mode of operation or second mode of operation.

2. the over-current protection system of circuit breaker according to claim 1 is characterized in that: also comprise the setting value input unit (600) with the two-way threshold values that is used for default single chip circuit (100) execution dropout action that is electrically connected of single chip circuit (100).

3. the over-current protection system of circuit breaker according to claim 1 and 2 is characterized in that: the communication ends of single chip circuit (100) is provided with and is used for the serial communication interface (800) that communicates with independent communication units or host computer (900).

4. the over-current protection system of circuit breaker according to claim 3, it is characterized in that: the off-line control input end of dropout drive circuit (400) is provided with off-line trip unit (130).

5. the over-current protection system of circuit breaker according to claim 4, it is characterized in that: the condition indicative signal output of single chip circuit (100) is provided with status indicator lamp (140).