CN2169852Y

CN2169852Y - Detecting instrument

Info

Publication number: CN2169852Y
Application number: CN 93231002
Authority: CN
Inventors: 林文宙; 柳玉高
Original assignee: Individual
Current assignee: Individual
Priority date: 1993-05-18
Filing date: 1993-05-18
Publication date: 1994-06-22
Anticipated expiration: 2003-05-18

Abstract

The utility model relates to an electrical meter of a low voltage wire, which is mainly composed of a probe, voltage divider, a hand-touch pole, an AC and DC transformer, a display meter, and a power source. The utility model is characterized in that the voltage divider is composed of components with high resistance values. The AC and DC transducer is composed of an integrated circuit and has the functions of high input impedance and linear rectification. When the utility model is used to measure voltage, the probe is used for contacting one point of a wire which is measured or one point of an electric apparatus which is measured, and the actual numerical value (a pointer type or a digital type) of voltage which is measured can be displayed. The meter can also be used for looking up the disconnection faults of insulated wires and the disconnection faults of the inner part of the insulated wires with the advantages of convenient operation, direct viewing, and portability.

Description

Detecting instrument

The utility model is the electrical instrument of a kind of instructed voltage existence and numerical values recited, and particularly a kind of detection instrument of measuring single-phase AC voltage and searching electrified wire intracutaneous disconnection fault belongs to the low-voltage circuit pick-up unit.

Under the prior art condition, carry out that voltage measurement always need be connected in parallel on the applied voltage table test line or by the electricity measurer two ends.This carries out the stationarity measurement to mounting instrument and is fine, but it is very inconvenient that provisional measurement is carried out in mobile operation.Though existing test pencil has test advantage simple, easy to use, can not survey the concrete data of voltage; Occurred a kind of digital test pencil in recent years, and used more conveniently, shortcoming is can only measure the voltage of surveying approximately to belong to which electric pressure, can not survey the concrete data of voltage.

The purpose of this utility model be to provide a kind of carry and use detection instrument is very easily all arranged, when carrying out the single-phase voltage measurement with this instrument, need not any line, a bit can measure virtual voltage numerical value with what the probe on this instrument contacted tested lead or electrical equipment live part, the insulation degree (hereinafter to be referred as impedance ground) between human body resistance and human body and the earth does not influence measurement effect; Can also detect the intracutaneous disconnection fault of electrified wire with this probe across insulation course.

Technical solution adopted in the utility model is, described detection instrument is touched the utmost point 3, AC-DC transducer 4, indicator gauge 5 and power supply 6 and is formed by probe 1, voltage divider 2, hand, special character is: voltage divider 2 is in series by high value element R1, R3 and three dividing potential drop links of higher resistance value element R2, and R ₁≈ R ₃" R2, R1 is electrically connected with probe 1, R3 is electrically connected with hand touched electrode 3, R2 is as sample resistance, its two ends are except that also being electrically connected with the input end and the COM end of AC-DC transducer 4 respectively respectively with R1, R3 are electrically connected, two input ends of indicator gauge 5 are connected the V of power supply 6 with the input end of AC-DC transducer 4 with the COM end respectively ₊End, V _-End and COM hold respectively the V with AC-DC transducer 4 ₊End, V _-End and the corresponding electrical connection of COM end.

In the technical program, three dividing potential drop link R1, R2, R3 of voltage divider 2 constitute by resistor, total resistance of connecting is not less than 500M Ω, wherein R2 is formed in parallel by R2a, R2b two circuit components, and K switch 2 of the branch road at R2b place series connection as gear shift, when the K2 disjunction, total resistance of dividing potential drop link R2 increases, and instrumental sensitivity further improves.Described AC-DC transducer 4 is to be voltage follower and the linear rectifier that main body constitutes by integrated operational amplifier.Described power supply 6 is made of battery and bleeder circuit, and V is arranged ₊, V _-, three terminals of COM.Described indicator gauge 5 can be pointer D.C. voltmeter, it also can be liquid crystal digital formula D.C. voltmeter, the former two unique terminals are the input end of this table, in the use it are electrically connected with the output terminal (being the A point among Fig. 1, Fig. 2 or Fig. 3) and the COM end of AC-DC transducer 4 respectively; The latter has four terminals---the input end (IN among Fig. 3, Fig. 4 ₊End), COM end, V ₊End and V _-End in the use, is electrically connected its input end, COM end respectively, with its V with output terminal, the COM end of AC-DC transducer 4 ₊End, V _-The end respectively with V AC-DC transducer 4 or power supply 6 ₊End, V _-End is electrically connected.

In the technique scheme, because the current-limiting resistance-voltage divider 2 total resistances that adopt high value are up to more than the 500M Ω, impedance ground can be ignored the influence of measurement result, can be convenient as existing test pencil in the use; Because indicator gauge 5 is housed, measurement result can be directly perceived as existing voltage table; Gear-shift switch K2 is housed, can utilizes this switch in the use, further improve the sensitivity of instrument, can detect the intracutaneous disconnection fault of electrified wire, have the not available function of existing test pencil and voltage table.

Below in conjunction with drawings and Examples the utility model is further specified.

Fig. 1 is main assembly of the present utility model and work synoptic diagram.

Fig. 2 is an embodiment of the present utility model.

Fig. 3 is another embodiment of the present utility model.

Fig. 4 is the supplementary notes of Fig. 3---the typical wiring figure of the digital D.C. voltmeter that constitutes for main body by LCDs and driving circuit 7106 thereof.

Among the figure: 1, probe; 2, voltage divider; 3, hand touches the utmost point; 4, AC-DC transducer; 5, indicator gauge; 6, power supply; E, battery; Z _D, impedance ground; R1, R2, R3, three dividing potential drop links of composition voltage divider 2; R2a, R2b, two bypass elements of composition R2; K1, cell switch; K2, Gear-shift switch; V ₊, V _-, COM, three terminals of power supply 6; IN ₊, IN _-, two input ends of the digital D.C. voltmeter that constitutes for main body by LCDs and driving circuit 7106 thereof.

With reference to description of drawings the utility model---the principle of work of detection instrument once.During use, staff contact hand touches the utmost point 3, when removing the contact electrification body with probe 1, just have at this moment electric current by pop one's head in 1, voltage divider 2, hand touch the utmost point 3 and impedance ground Z _DFlow back to the line of electric force neutral point.Usually, impedance ground Z _DAlong with the different difference of situation are very big, little several K Ω is big to several M Ω.But,, go up the anti-Z of stake resistance of several K Ω or several M Ω to its series connection up to hundreds of M Ω because the resistance of the voltage divider of getting 2 is bigger _DAfter, to the influence of total resistance seldom, and because of Z _DNot pure resistance character, Z _DConnect the total resistance in back with voltage divider 2 less than both algebraic sum, and therefore, the electric current by the loop in the measurement is only relevant with tested voltage with the resistance of voltage divider 2, impedance ground Z _DThe influence of either large or small generation can be ignored.Must produce a voltage drop at the R2 two ends by loop current in the measurement, that is to say, R2 has the joint power taking to press the effect of signal; Be connected into the voltage follower form because AC-DC transducer 4 primes are integrated operational amplifier A1, distinguishing feature is to have very high input impedance, and the voltage signal that the R2 joint is got produces the bypass attenuation hardly; Because the back level of AC-DC transducer 4 is to be connected into the linear semi-wave commutation device with integrated operational amplifier A2 and R4, R5, R6, D1, D2, characteristics are to convert the alternating voltage that prime is sent here to DC voltage by proportional relation again; Indicator gauge 5 is pointer-type or digital D.C. voltmeter, to indicate from the DC voltage of AC-DC transducer 4, adjust potentiometer W, the registration that can make indicator gauge 5 just in time with tested voltage---promptly pop one's head in 1 and the earth between the actual numerical value of voltage corresponding.When Gear-shift switch K2 dials at open position, the resistance of sample resistance R2 becomes big (becoming R2=K2a by R2=R2a ∥ R2b), the voltage signal that its joint is got strengthens, this moment, the sensitivity of detection instrument further improved, can detect the variation of electrified wire voltage-to-ground across insulation course, thereby judge the guilty culprit of disconnected intracutaneous line.

In the embodiment shown in Figure 2, power supply 6 is made up of battery E and voltage stabilizing diode Dw, resistor R 7 and cell switch K1, and wherein Dw, R7 form bleeder circuit, and its effect is single supply---and battery becomes and has V ₊, V _-With the power supply of three terminals of COM, to satisfy the need of work of AC-DC transducer 4.Present embodiment indicator gauge 5 usefulness be pointer D.C. voltmeter, two unique terminals of this table are input end, according to the polarity at two ends respectively with the output terminal and COM corresponding connection of end of AC-DC transducer 4.

In the embodiment shown in fig. 3, indicator gauge 5 usefulness be liquid crystal digital formula D.C. voltmeter, this table comprises that driving circuit and LCDs two parts form, what wherein driving circuit was used is large scale integrated circuit 7106, itself removes input end IN ₊, IN _-Outward (with one of them IN _-Merge with COM), also be provided with V ₊End (the 1st pin), V _-End (the 26th pin) and COM end (the 32nd pin), and V ₊And the very high 2.8V voltage of a stationary value is arranged between COM, when the both positive and negative polarity of battery E respectively with V ₊, V _-After joining, 7106 itself just form a good bleeder circuit, with its V ₊End, V _-End and COM end can make the complete machine operate as normal after joining with the corresponding end of AC-DC transducer 4 just, suitably choose the numerical value of R4, R5, R6, suitably adjust W, just can make the difunctional detection instrument of liquid crystal digital display type.In addition, in the present embodiment, also with the filtering circuit of forming by C1, R8, C2, can make the more level and smooth DC voltage of AC-DC transducer 4 outputs like this, the unlikely serious sudden strain of a muscle of liquid crystal digital formula voltage table designation number is jumped in AC-DC transducer 4 back levels.

Choosing of components and parts provides following reference:

In Fig. 2 or embodiment illustrated in fig. 3, housing selects for use the ABS injected plastics material to make; The reinforcing bar of probe 1 usefulness φ 4mm is made and is about 50mm, the end flat; Hand touches the utmost point 3 usefulness iron plates and makes garden shape; A1, A2 are with integrated double operational SF358; All resistors are all used the 0.125W carbon resister, R1=R3=330M Ω wherein, R2a=510K Ω, R2b=1.2M Ω; W 33K Ω carbon-film potentiometer; Among Fig. 2, R4=100K Ω, R5=82K Ω, R6=390K Ω; DW 2CW52 type voltage stabilizing diode; Indicator gauge 5 usefulness 25 * 15mm decibel meter, range 600mV makes scale by 0.5V/mV.Among Fig. 3, R4=100K Ω, R5=47K Ω, R6=91K Ω, R8=220K Ω, C1=C2=1uF; Indicator gauge 5 is that the typical case of this table constitutes as shown in Figure 4 with the attached digital D.C. voltmeter that constitutes with 7106 driving circuits and other peripheral cell of 27 * 50.8mm LCDs.

Claims

1, a kind ofly touches the detection instrument that the utmost point (3), AC-DC transducer (4), display (5) and power supply (6) are formed by probe (1), voltage divider (2), hand, it is characterized in that: voltage divider 2 is in series by high value element R1, R3 and three dividing potential drop links of higher resistance value element R2, and R1 ≈ R3 " R2, R1 is electrically connected with probe (1), R3 touches the utmost point (3) with hand and is electrically connected, R2 is as sample resistance, its two ends are except that also being electrically connected the V of power supply (6) with the output terminal and the COM end of AC-DC transducer (4) respectively respectively with R1, R3 are electrically connected ₊End, V _-End and COM hold respectively the V with AC-DC transducer (4) ₊End, V _-End and the corresponding electrical connection of COM end.

2, by the described detection instrument of claim 1, it is characterized in that: three dividing potential drop link R1, R2, R3 of voltage divider (2) constitute by resistor, and total resistance of connecting is not less than 500M Ω.

3, by claim 1 or 2 described detection instruments, it is characterized in that: R2 is formed in parallel by R2a, R2b two circuit components in the voltage divider (2), wherein K switch 2 of the branch road at R2b place series connection.

4, by the described detection instrument of claim 1, it is characterized in that: AC-DC transducer (4) is to be voltage follower and the linear rectifier that main body constitutes by integrated operational amplifier.

5, by the described detection instrument of claim 1, it is characterized in that: power supply (6) is made up of battery and bleeder circuit and V is arranged ₊, V _-With three terminals of COM.

6, by the described detection instrument of claim 1, it is characterized in that: indicator gauge (5) is pointer D.C. voltmeter, and two terminals is two input ends of this table.

7, by the described detection instrument of claim 1, it is characterized in that: indicator gauge (5) is a liquid crystal digital display type D.C. voltmeter, two input end N ₊, N _-, the output terminal with AC-DC transducer (4) is electrically connected, and another is electrically connected its V with the COM end ₊End, V _-End respectively with the V of AC-DC transducer (4) or power supply (6) ₊End, V _-End is electrically connected.