CN105572578A

CN105572578A - Improved detection device for testing residual-current circuit breaker

Info

Publication number: CN105572578A
Application number: CN201610078280.7A
Authority: CN
Inventors: 胡小青
Original assignee: Individual
Current assignee: Individual
Priority date: 2012-07-27
Filing date: 2012-07-27
Publication date: 2016-05-11
Also published as: CN105699885A; CN105572579A; CN105606995A; CN105699886A; CN105699887A; CN102749579B; CN102749579A; CN105699887B

Abstract

The present invention relates to an improved detection device for testing a residual-current circuit breaker. The improved detection device includes an alternating current power source circuit, a phase generation circuit, an alternating current leakage adjustment circuit and a time detection circuit; the phase generation circuit includes a direct current generation circuit; the direct current generation circuit is composed of a resistor R67, a 9V dry battery Bt and button switches SB5 and SB6; one end of the resistor R67 is connected with the positive pole of the 9V dry battery U; the other end of the resistor R67 is connected with the intermediate contact of the button switch SB5; the normally-open contact of the button switch SB5 is connected with the normally-open contact and normally-closed contact of the button switch SB6; the negative pole of the 9V dry battery is connected with the normally-open contact of the button switch SB6; the intermediate contact of the button switch SB6 is connected with a direct current output wiring terminal ''+''; and the intermediate contact SB6-21 of the button switch SB6 is connected with direct current output ''-''. The improved detection device of the invention is reasonable in structure and can meet the special needs of users.

Description

A kind of modified checkout equipment for testing residual current circuit breaker

Technical field

The present invention relates to a kind of modified checkout equipment.

Background technology

According to standard GB/T 14048.2-2001, GB16916.1-2003, the regulations such as GB16917.1-2003: to no matter being the residue pulsating direct current with regulation or residue simple sinusoidal alternating current that apply suddenly or slowly rise, can guarantee that the residual current circuit breaker of threading off at the appointed time is called A type residual current circuit breaker.To no matter being the residue simple sinusoidal alternating current had without DC component applying suddenly or slowly rise, the residual current circuit breaker of threading off at the appointed time can being guaranteed, be called AC type residual current circuit breaker.As from the foregoing, A type residual current circuit breaker covers the function of AC type residual current circuit breaker.

Above-mentioned " the residue pulsating current of regulation " is following 4 kinds of situations: the half-wave rectified current of the half-wave rectified current of current lagging voltage 0o, the half-wave rectified current of current lagging voltage 90o, the half-wave rectified current of current lagging voltage 135o, the current lagging voltage 0o containing 6mA direct current.

The device that A type residual current circuit breaker is measured is there is not in prior art.

Summary of the invention

Technical matters to be solved by this invention is to provide the comparatively wide and modified checkout equipment for testing residual current circuit breaker that performance is comparatively reliable and stable of a kind of test specification.

For solving the problems of the technologies described above, the invention provides a kind of modified checkout equipment for testing residual current circuit breaker, comprising AC power circuit, DC power-supply circuit, phase generating circuit, ac leakage regulating circuit, phase place display circuit, indicator light circuit and time detection circuit, it is characterized in that: AC power circuit has the first live wire end for forming load circuit and the second live wire end for forming simulation loop of electric leakage, first live wire end and the second live wire end are used for being connected with the live wire input end of equipment under test, and the zero line side of described load circuit is used for being connected with the zero line side of equipment under test, described equipment under test is A type residual current circuit breaker, phase generating circuit is used for being connected with the fire wire output end L2 of equipment under test, phase generating circuit comprises control knob circuit, and control knob circuit is used for control phase and produces the half-wave rectified current that circuit generates the half-wave rectified current of current lagging voltage 0o, the half-wave rectified current of current lagging voltage 90o, the half-wave rectified current of current lagging voltage 135o and the current lagging voltage 0o containing 6mA direct current respectively in described simulation loop of electric leakage, ac leakage regulating circuit is for controlling the size of current of described simulation loop of electric leakage, time detection circuit is for measuring the time from the conducting of described simulation loop of electric leakage to A type residual current circuit breaker needed for dropout, i.e. actuation time, described phase generating circuit comprises: first half-wave rectifying circuit of current lagging voltage 0o, second half-wave rectifying circuit of current lagging voltage 90o, 3rd half-wave rectifying circuit of current lagging voltage 135o, 6mA direct current generative circuit and controllable silicon current control circuit, controllable silicon current control circuit is used for according to described first half-wave rectifying circuit, the control signal that second half-wave rectifying circuit and the 3rd half-wave rectifying circuit export generates the half-wave rectified current of current lagging voltage 0o respectively in described simulation loop of electric leakage, the half-wave rectified current of current lagging voltage 90o, the half-wave rectified current of the half-wave rectified current of current lagging voltage 135o and the current lagging voltage 0o containing 6mA direct current, 3rd half-wave rectifying circuit of described current lagging voltage 135o comprises: the sine wave shaped be made up of with operational amplifier IC1A transformer T2, diode D5, resistance R3, R4, R5, R6, R7 becomes circuit, the charging circuit be made up of resistance R8, electric capacity C5 be connected with the output terminal of operational amplifier IC1A, be made up of diode D6, D7 with door, be used for setting resistance R9 and R10 relative to the voltage of adjusting of current lagging voltage 135o, being used for the resistance R11 of the comparative voltage relative to current lagging voltage 135o of the backward end regulating operational amplifier IC1B and the output terminal of potentiometer WR1, operational amplifier IC1B is used for the control signal of output current lagging voltage 135o, resistance R12 is the current-limiting resistance of triode BG3 base stage, triode BG3 and resistance R13 forms emitter follower, the control signal of the current lagging voltage 135o on resistance R13 gives triode BG18 by pushbutton switch SB1, resistance R58, triode BG18 drives opto-coupler chip IC4, resistance R59 is current-limiting resistance, ensures that opto-coupler chip IC4 effectively works, opto-coupler chip IC4 is in order to isolate alternating current 220V and phase generating circuit direct current component, control the turn-on and turn-off of bidirectional triode thyristor BG19, resistance R60, R61, for controlling the G pole input current of bidirectional triode thyristor BG19, make input signal enough trigger bidirectional triode thyristor BG19 conducting, bidirectional triode thyristor BG19 A, K bis-pole be connected between load and AC power, the electric current flowing through load is exactly the half-wave rectified current lagging behind voltage 135o, control bidirectional triode thyristor BG19 and get final product the residue pulsating current passing through regulation in operation circuit, regulator potentiometer WR3, WR4, WR5 can control leakage current, when pushbutton switch SB10 closes, two intermediate contacts of pushbutton switch SB10 are used for the detection of phase generating circuit output waveform, described controllable silicon current control circuit comprises: the control signal exported according to described first half-wave rectifying circuit, the second half-wave rectifying circuit and the 3rd half-wave rectifying circuit and the triode BG18 of conducting, the opto-coupler chip IC4 that driven by triode BG18, controlled the bidirectional triode thyristor BG19 of break-make by opto-coupler chip IC4, A, K pole of bidirectional triode thyristor BG19 is connected in described simulation loop of electric leakage, described time detection circuit comprises: single-chip microcomputer IC6, be connected with the detection of electrical leakage end of single-chip microcomputer IC6 for detecting the described simulation loop of electric leakage whether leakaging signal detecting circuit of conducting and the charactron for displaying time that is connected with the temporal information output terminal of single-chip microcomputer IC6, single-chip microcomputer IC6 measures the time from the conducting of described simulation loop of electric leakage to A type residual current circuit breaker needed for dropout according to the electric leakage signal that leakaging signal detecting circuit exports and passes through this time of described numeral method, described 6mA direct current generative circuit is made up of resistance R67,9V dry cell Bt, pushbutton switch SB5, SB6, one end of resistance R67 is connected with the positive pole of 9V dry cell U, the other end of resistance R67 is connected with the intermediate contact of pushbutton switch SB5, the normally opened contact of pushbutton switch SB5 is connected with the normally opened contact of pushbutton switch SB6, normally closed contact, 9V dry battery cathode connects the normally opened contact of pushbutton switch SB6, the intermediate contact of pushbutton switch SB6 is connected with direct current output wiring terminal "+", and intermediate contact SB6-21 and the direct current of pushbutton switch SB6 export "-" and be connected,

Indicator light circuit is made up of transformer T4, commutation diode D42-45, three terminal regulator BG27, RC filtering circuit; DC power-supply circuit 7 comprises: the 5V DC power-supply circuit of being powered by transformer T1, the 5V DC power-supply circuit of being powered by transformer T3,12V DC power-supply circuit and 6mA direct current generative circuit.

The present invention has positive effect: the present invention, by improving direct current generative circuit, makes its structure comparatively reasonable, effectively can meet the testing requirement of special residual current circuit breaker.

Accompanying drawing explanation

Be further explained the present invention below in conjunction with accompanying drawing, wherein accompanying drawing is as follows:

Fig. 1 is the contour structures schematic diagram of the modified checkout equipment of embodiment 1;

Fig. 2 is the part electrical schematic diagram of the modified checkout equipment of embodiment 1;

Fig. 3 is another part electrical schematic diagram of the modified checkout equipment of embodiment 1.

Embodiment

(embodiment 1)

See Fig. 1-3, the present embodiment is a kind of modified checkout equipment for testing residual current circuit breaker, comprising: AC power circuit 1, DC power-supply circuit 7, phase generating circuit 2, ac leakage regulating circuit 3, phase place display circuit 6, indicator light circuit 5 and time detection circuit 4.

AC power circuit 1 has the first live wire end for forming load circuit and the second live wire end for forming simulation loop of electric leakage, first live wire end and the second live wire end are used for being connected with the live wire input end of equipment under test 9, and the zero line side of described load circuit is used for being connected with the zero line side of equipment under test 9.In the present embodiment, equipment under test 9 is A type residual current circuit breaker.

Phase generating circuit 2 is for being connected with the fire wire output end L2 of equipment under test 9; Phase generating circuit 2 comprises control knob circuit, and control knob circuit is used for control phase and produces the half-wave rectified current that circuit 2 generates the half-wave rectified current of current lagging voltage 0o, the half-wave rectified current of current lagging voltage 90o, the half-wave rectified current of current lagging voltage 135o and the current lagging voltage 0o containing 6mA direct current respectively in described simulation loop of electric leakage.

Ac leakage regulating circuit 3 is for controlling the size of current of described simulation loop of electric leakage; Time detection circuit 4 is for measuring the time from the conducting of described simulation loop of electric leakage to A type residual current circuit breaker needed for dropout, i.e. actuation time.

Described phase generating circuit 2 comprises: first half-wave rectifying circuit of current lagging voltage 0o, second half-wave rectifying circuit of current lagging voltage 90o, 3rd half-wave rectifying circuit of current lagging voltage 135o, 6mA direct current generative circuit, and for according to described first half-wave rectifying circuit, the control signal that second half-wave rectifying circuit and the 3rd half-wave rectifying circuit export generates the half-wave rectified current of current lagging voltage 0o respectively in described simulation loop of electric leakage, the half-wave rectified current of current lagging voltage 90o, the controllable silicon current control circuit of the half-wave rectified current of the half-wave rectified current of current lagging voltage 135o and the current lagging voltage 0o containing 6mA direct current.

3rd half-wave rectifying circuit of described current lagging voltage 135o comprises: the sine wave shaped be made up of with operational amplifier IC1A transformer T2, diode D5, resistance R3, R4, R5, R6, R7 becomes circuit, the charging circuit be made up of resistance R8, electric capacity C5 be connected with the output terminal of operational amplifier IC1A, be made up of diode D6, D7 with door; Be used for setting resistance R9 and R10 relative to the voltage of adjusting of current lagging voltage 135o, being used for the resistance R11 of the comparative voltage relative to current lagging voltage 135o of the backward end regulating operational amplifier IC1B and the output terminal of potentiometer WR1, operational amplifier IC1B is used for the control signal of output current lagging voltage 135o.

Resistance R12 is the current-limiting resistance of triode BG3 base stage, triode BG3 and resistance R13 forms emitter follower, the control signal of the current lagging voltage 135o on resistance R13 gives triode BG18 by pushbutton switch SB1, resistance R58, triode BG18 drives opto-coupler chip IC4, resistance R59 is current-limiting resistance, ensures that opto-coupler chip IC4 effectively works.Opto-coupler chip IC4 is in order to isolate alternating current 220V and phase generating circuit direct current component, control the turn-on and turn-off of bidirectional triode thyristor BG19, resistance R60, R61, for controlling the G pole input current of bidirectional triode thyristor BG19, make input signal enough trigger bidirectional triode thyristor BG19 conducting.Bidirectional triode thyristor BG19 A, K bis-pole be connected between load and AC power, the electric current flowing through load is exactly the half-wave rectified current lagging behind voltage 135o.Control bidirectional triode thyristor BG19 and get final product the residue pulsating current passing through regulation in operation circuit, regulator potentiometer WR3, WR4, WR5 can control leakage current.

When pushbutton switch SB10 closes, two intermediate contacts of pushbutton switch SB10 are used for the detection of phase generating circuit output waveform.

Described controllable silicon current control circuit comprises: the control signal exported according to described first half-wave rectifying circuit, the second half-wave rectifying circuit and the 3rd half-wave rectifying circuit and the triode BG18 of conducting, the opto-coupler chip IC4 that driven by triode BG18, controlled the bidirectional triode thyristor BG19 of break-make by opto-coupler chip IC4, A, K pole of bidirectional triode thyristor BG19 is connected in described simulation loop of electric leakage.

Described time detection circuit 4 comprises: single-chip microcomputer IC6, be connected with the detection of electrical leakage end of single-chip microcomputer IC6 for detecting the described simulation loop of electric leakage whether leakaging signal detecting circuit of conducting and the charactron for displaying time that is connected with the temporal information output terminal of single-chip microcomputer IC6; Single-chip microcomputer IC6 measures the time from the conducting of described simulation loop of electric leakage to A type residual current circuit breaker needed for dropout according to the electric leakage signal that leakaging signal detecting circuit exports and passes through this time of described numeral method.

Described phase generating circuit 2 is connected with the phase place display circuit 6 that there is the half-wave rectified current of the half-wave rectified current of the half-wave rectified current of current lagging voltage 0o or the half-wave rectified current of current lagging voltage 90o or current lagging voltage 135o or the current lagging voltage 0o containing 6mA direct current for showing described simulation loop of electric leakage.

AC power circuit is by 220V50Hz ac power supply to transformer T4, and transformer T4 exports 180V, 220V, 250V, 380V voltage and is connected on interchange output wiring terminal L1, N through waver SA1.By the gear of adjusting band switch SA1, the voltage exchanging output wiring terminal L1 and N two ends can be changed.The load of transformer T4 is ac leakage regulating circuit 3.

Ac leakage regulating circuit 3 exports 26V alternating current by transformer T4, its output terminal one end is connected to after connecting with waver SA2 and exchanges output wiring terminal L1, after the other end is connected with reometer, the regulating resistance that leaks electricity, bidirectional triode thyristor BG19, waver SA3, be connected to and exchange output wiring terminal L2.

The logical circuit that phase place display circuit 6 is made up of charactron LED1-LED4, diode D11-36, triode BG7-16, pushbutton switch form.

When pressing the button switch S B4, current signal trigger triode BG20 conducting, triode BG20 outputs signal trigger triode BG7, BG8 conducting, and charactron LED1 shows " A ", and charactron LED2 shows " C ".When pressing the button switch S B3, charactron LED1, LED4 show " A0 "; Press the button switch S B2, charactron LED1, LED3, LED4 show " A90 "; Press the button switch S B5, charactron LED1, LED2, LED3, LED4 show " A0-6 ".

Indicator light circuit 5 is made up of transformer T4, commutation diode D42-45, three terminal regulator BG27, RC filtering circuit.DC power-supply circuit 7 comprises: the 5V DC power-supply circuit of being powered by transformer T1, the 5V DC power-supply circuit of being powered by transformer T3,12V DC power-supply circuit, 6mA direct current generative circuit.

Time detection circuit 4 is made up of pushbutton switch, commutation diode D46-49, triode BG23-26, resistance, electric capacity C15, photoelectrical coupler IC5, single-chip microcomputer IC6, charactron LED11 etc.

6mA direct current generative circuit is made up of resistance R67,9V dry cell Bt, pushbutton switch SB5, SB6.One end of resistance R67 is connected with the positive pole of 9V dry cell U, the other end of resistance R67 is connected with the intermediate contact of pushbutton switch SB5, the normally opened contact of pushbutton switch SB5 is connected with the normally opened contact of pushbutton switch SB6, normally closed contact, 9V dry battery cathode connects the normally opened contact of pushbutton switch SB6, normally opened contact is connected, the intermediate contact of pushbutton switch SB6 is connected with direct current output wiring terminal "+", and intermediate contact SB6-21 and the direct current of pushbutton switch SB6 export "-" and be connected.

Second half-wave rectifying circuit of current lagging voltage 90o is by resistance R17, R18, R19, R20, R21, R22, R23, R24, R25, R26, R27, R57, R58, R59, R60, R61, electric capacity C6, diode D8, D9, D10, triode BG5, BG18, bidirectional triode thyristor BG19, operational amplifier IC2, opto-coupler chip IC4, potentiometer WR2 are formed.

First half-wave rectifying circuit of current lagging voltage 0o is by resistance R50, R51, R52, R53, R54, R55, R56, R57, R58, R59, R60, R61, diode D37, triode BG17, BG18, bidirectional triode thyristor BG19, operational amplifier IC3, opto-coupler chip IC4 are formed.The positive terminal of diode D51 is extremely connected with the e of the triode BG22 in phase place display circuit, the negative pole end of diode D51 is connected with one end of resistance R75, the other end of resistance R75 is extremely connected with the b of triode BG28,2 pin of opto-coupler chip IC7 are extremely connected with the c of triode BG28, and the e pole of triode BG28 is connected with 2 pin of stabilivolt BG21.One end of resistance R74 is connected with 3 pin of stabilivolt BG21, and 4,6 pin of opto-coupler chip IC7 are connected with pushbutton switch SB3 intermediate contact SB3-21, normally opened contact SB3-22 respectively.Because there being the half-wave rectified current containing 6mA direct current of current lagging voltage 0o in " the residue pulsating current of regulation ", therefore this part when " A0-6 ", ensures the output of the half-wave rectified current of current lagging voltage 0o for realizing.

Resistance R73, R77 are the current-limiting resistance of opto-coupler chip IC5, resistance R78 is the current-limiting resistance of 1 pin of single-chip microcomputer IC6, electric capacity C15, resistance R79 form differentiating circuit, resistance R80, R81, R82, R83, R84, R85, R86, R87 are the current-limiting resistance of each pin of charactron LED11, and resistance R88, R89, R90, R91 are the current-limiting resistance of the b pole of triode BG23, BG24, BG25, BG26.Pushbutton switch SB17 is testing button, and pushbutton switch SB18 is reset button.

When pushbutton switch SB17 closes, breaker electrifying, DC current forms a spike pulse through differentiating circuit, and 1 pin of input single-chip microcomputer IC6, single-chip microcomputer IC6 starts timing.When circuit breaker trip, opto-coupler chip IC5 dead electricity, 4,6 pin turn off, and 3 pin of single-chip microcomputer IC6 have high level to input, and single-chip microcomputer IC6 stops timing and export data showing to charactron LED11.When pushbutton switch SB18 presses, single-chip microcomputer IC6, charactron LED11 reset.

Above-described embodiment is only for example of the present invention is clearly described, and is not the restriction to embodiments of the present invention.For those of ordinary skill in the field, can also make other changes in different forms on the basis of the above description.Here exhaustive without the need to also giving all embodiments.And these belong to spirit institute's apparent change of extending out of the present invention or change and are still among protection scope of the present invention.

Claims

1., for testing a modified checkout equipment for residual current circuit breaker, comprise AC power circuit, DC power-supply circuit, phase generating circuit, ac leakage regulating circuit, phase place display circuit, indicator light circuit and time detection circuit, it is characterized in that: AC power circuit has the first live wire end for forming load circuit and the second live wire end for forming simulation loop of electric leakage, first live wire end and the second live wire end are used for being connected with the live wire input end of equipment under test, and the zero line side of described load circuit is used for being connected with the zero line side of equipment under test, described equipment under test is A type residual current circuit breaker, phase generating circuit is used for being connected with the fire wire output end L2 of equipment under test, phase generating circuit comprises control knob circuit, and control knob circuit is used for control phase and produces the half-wave rectified current that circuit generates the half-wave rectified current of current lagging voltage 0o, the half-wave rectified current of current lagging voltage 90o, the half-wave rectified current of current lagging voltage 135o and the current lagging voltage 0o containing 6mA direct current respectively in described simulation loop of electric leakage, ac leakage regulating circuit is for controlling the size of current of described simulation loop of electric leakage, time detection circuit is for measuring the time from the conducting of described simulation loop of electric leakage to A type residual current circuit breaker needed for dropout, i.e. actuation time, described phase generating circuit comprises: first half-wave rectifying circuit of current lagging voltage 0o, second half-wave rectifying circuit of current lagging voltage 90o, 3rd half-wave rectifying circuit of current lagging voltage 135o, 6mA direct current generative circuit and controllable silicon current control circuit, controllable silicon current control circuit is used for according to described first half-wave rectifying circuit, the control signal that second half-wave rectifying circuit and the 3rd half-wave rectifying circuit export generates the half-wave rectified current of current lagging voltage 0o respectively in described simulation loop of electric leakage, the half-wave rectified current of current lagging voltage 90o, the half-wave rectified current of the half-wave rectified current of current lagging voltage 135o and the current lagging voltage 0o containing 6mA direct current, 3rd half-wave rectifying circuit of described current lagging voltage 135o comprises: the sine wave shaped be made up of with operational amplifier IC1A transformer T2, diode D5, resistance R3, R4, R5, R6, R7 becomes circuit, the charging circuit be made up of resistance R8, electric capacity C5 be connected with the output terminal of operational amplifier IC1A, be made up of diode D6, D7 with door, be used for setting resistance R9 and R10 relative to the voltage of adjusting of current lagging voltage 135o, being used for the resistance R11 of the comparative voltage relative to current lagging voltage 135o of the backward end regulating operational amplifier IC1B and the output terminal of potentiometer WR1, operational amplifier IC1B is used for the control signal of output current lagging voltage 135o, resistance R12 is the current-limiting resistance of triode BG3 base stage, triode BG3 and resistance R13 forms emitter follower, the control signal of the current lagging voltage 135o on resistance R13 gives triode BG18 by pushbutton switch SB1, resistance R58, triode BG18 drives opto-coupler chip IC4, resistance R59 is current-limiting resistance, ensures that opto-coupler chip IC4 effectively works, opto-coupler chip IC4 is in order to isolate alternating current 220V and phase generating circuit direct current component, control the turn-on and turn-off of bidirectional triode thyristor BG19, resistance R60, R61, for controlling the G pole input current of bidirectional triode thyristor BG19, make input signal enough trigger bidirectional triode thyristor BG19 conducting, bidirectional triode thyristor BG19 A, K bis-pole be connected between load and AC power, the electric current flowing through load is exactly the half-wave rectified current lagging behind voltage 135o, control bidirectional triode thyristor BG19 and get final product the residue pulsating current passing through regulation in operation circuit, regulator potentiometer WR3, WR4, WR5 can control leakage current, when pushbutton switch SB10 closes, two intermediate contacts of pushbutton switch SB10 are used for the detection of phase generating circuit output waveform, described controllable silicon current control circuit comprises: the control signal exported according to described first half-wave rectifying circuit, the second half-wave rectifying circuit and the 3rd half-wave rectifying circuit and the triode BG18 of conducting, the opto-coupler chip IC4 that driven by triode BG18, controlled the bidirectional triode thyristor BG19 of break-make by opto-coupler chip IC4, A, K pole of bidirectional triode thyristor BG19 is connected in described simulation loop of electric leakage, described time detection circuit comprises: single-chip microcomputer IC6, be connected with the detection of electrical leakage end of single-chip microcomputer IC6 for detecting the described simulation loop of electric leakage whether leakaging signal detecting circuit of conducting and the charactron for displaying time that is connected with the temporal information output terminal of single-chip microcomputer IC6, single-chip microcomputer IC6 measures the time from the conducting of described simulation loop of electric leakage to A type residual current circuit breaker needed for dropout according to the electric leakage signal that leakaging signal detecting circuit exports and passes through this time of described numeral method, described 6mA direct current generative circuit is made up of resistance R67,9V dry cell Bt, pushbutton switch SB5, SB6, one end of resistance R67 is connected with the positive pole of 9V dry cell U, the other end of resistance R67 is connected with the intermediate contact of pushbutton switch SB5, the normally opened contact of pushbutton switch SB5 is connected with the normally opened contact of pushbutton switch SB6, normally closed contact, 9V dry battery cathode connects the normally opened contact of pushbutton switch SB6, the intermediate contact of pushbutton switch SB6 is connected with direct current output wiring terminal "+", and intermediate contact SB6-21 and the direct current of pushbutton switch SB6 export "-" and be connected,