CN2280917Y - Digital insulation resistance meter - Google Patents
Digital insulation resistance meter Download PDFInfo
- Publication number
- CN2280917Y CN2280917Y CN 96235155 CN96235155U CN2280917Y CN 2280917 Y CN2280917 Y CN 2280917Y CN 96235155 CN96235155 CN 96235155 CN 96235155 U CN96235155 U CN 96235155U CN 2280917 Y CN2280917 Y CN 2280917Y
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- China
- Prior art keywords
- voltage
- resistance
- circuit
- series
- current
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- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
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Abstract
The utility model relates to an electric measuring instrument for checking insulation resistance, comprising a DC high-voltage voltage-stabilizing source, a voltage and current sampling circuit, an automatic range switching circuit, a double-integrating analog to digital converter and a digital display circuit, wherein, the voltage and current sampling circuit comprises two parallel branches which are a voltage sampling branch and a current sampling circuit which is formed by that a sampling resistor which can be connected with a measured resistor and a fixed resistor are connected in series. The node point arranged between the two resistors is provided with a low-pressure end of sampled signals of voltage and current. The sampling resistor is formed by series connection of resistors. The node point between the resistors connected in series is led to the high-pressure end of sampled signals of current by a switch. The digital insulation resistance meter having wide measuring range overcomes the defect of low precision for measuring lower limit in the prior art and can realize automatic range conversion.
Description
The utility model relates to a kind of electrical measuring instrument that detects the insulating resistance value of electrical equipment, supply line, insulating material etc.
The instrument that is used to detect insulating resistance value at present mainly contains two classes: 1, pointer megohmmeter (megger).Form by hand generator and magnetoelectricity series ratiometer, use very inconvenient, and test voltage shakiness, influence test result accurately, pointer-type shows also makes reading error bigger.2, digital megohmmeter.Constitute by electronic circuit fully, adopt battery or mains-supplied, show measurement result, improved measuring accuracy with numeral.As apply for that CN86105996A discloses and a kind ofly can realize that the numerical megger of automatic switching range is exactly an example, but should table exist when tested resistance hour measuring error obviously become big defective.
The purpose of this utility model provides a kind of digital insulation resistance meter, can not only automatic switching range, can also hour not influence measuring accuracy in tested resistance.
Scheme of the present utility model is: comprise the high direct voltage source of stable pressure, the electric current and voltage sample circuit, the automatic range commutation circuit, double integration A/D converter and digital display circuit, the electric current and voltage sample circuit connects the input end of high direct voltage source of stable pressure and its output termination double integration A/D converter, the output termination automatic range commutation circuit and the digital display circuit of double integration A/D converter, wherein the electric current and voltage sample circuit comprises two parallel branches: voltage sampling branch road and current sampling circuit, voltage sample circuit is made of resistance in series, node between the resistance in series is provided with the voltage sampling signal high-pressure side, its difference is that current sampling circuit is connected with fixed resistance by the sample resistance that can be connected in series measured resistance and constituted, node is established voltage between two resistance, the current sampling signal low pressure end, sample resistance is made of resistance series connection, rolls that node leads to the current sampling signal high-pressure side by switch between the resistance in series.
The utility model voltage and current sampled signal is the poor of corresponding high-pressure side and low pressure end current potential, this signal voltage and current strict all the time and on the measured resistance is directly proportional, make this ohmmeter measurement range wide, overcome the low shortcoming of measurement lower limit measuring accuracy in the prior art, and can realize the automatic range conversion.
Fig. 1 is the utility model structural drawing.
Fig. 2 is the circuit diagram of electric current and voltage sample circuit.
Electric current and voltage sample circuit 2 links with high direct voltage source of stable pressure 1, and the voltage and current sampled signal is sent into the input end of double integration A/D converter 4, its output termination automatic range commutation circuit 3 and digital display circuit 5.This double integration A/D converter can adopt ICL7106,7126 or 5G7135 etc.
This electric current and voltage sample circuit comprises two branch roads parallel with one another as shown in Figure 2.Wherein voltage sampling props up two resistance R 1 of route, R2 formation of connecting, and its intermediate node is voltage sampling signal high-pressure side V
V+Current sampling circuit is by being connected in series measured resistance R
XSample resistance R
SSeries connection constitutes with fixed resistance R3, and the node between them is voltage, current sampling signal low pressure end V
V-, V
I-Sample resistance Rs comprises four resistance in series R
S1-R
S4, node is drawn by electronic switch K1-K4 respectively between node between them and R4 and the RX, as current sampling signal high-pressure side V
I+The output terminal of the control end of above-mentioned K1-K4 and automatic range commutation circuit links, and changes R by this circuit control break-make
SResistance, thus reach the purpose that changes range.
The utility model puts on high pressure on the measured resistance Rx when work, obtains voltage sampling signal V by voltage sample circuit
V=V
V+-V
V-, the selecting circuit parameter makes R1/R2=R
S/ R3 can make V
VAll the time with R
XBoth end voltage is directly proportional.Equally, V
V=V
I+-V
I-And V
IWith flow through R
XElectric current be directly proportional.With V
V+And V
V-Connect the Vin end of double integration A/D converter, V
I+And V
I-Meet this circuit V
REFEnd makes it carry out division arithmetic in the A/D conversion.The double integration A/D converter output signal directly drives the digital display circuit display result, and the automatic range commutation circuit is according to this output signal control R
SValue, and the demonstration of selection digital display circuit radix point.
Claims (1)
1, a kind of digital insulation resistance meter, comprise the high direct voltage source of stable pressure, the electric current and voltage sample circuit, the automatic range commutation circuit, double integration A/D converter and digital display circuit, the electric current and voltage sample circuit connects the input end of high direct voltage source of stable pressure and its output termination double integration A/D converter, the output termination automatic range commutation circuit and the digital display circuit of double integration A/D converter, wherein the electric current and voltage sample circuit comprises two parallel branches: voltage sampling branch road and current sampling circuit, voltage sample circuit is made of resistance in series, node between the resistance in series is provided with the voltage sampling signal high-pressure side, it is characterized in that current sampling circuit is connected with fixed resistance by the sample resistance that can be connected in series measured resistance constitutes, node is established voltage between two resistance, the current sampling signal low pressure end, sample resistance is made of the resistance series connection, and node leads to the current sampling signal high-pressure side by switch between this resistance in series.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 96235155 CN2280917Y (en) | 1996-06-24 | 1996-06-24 | Digital insulation resistance meter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 96235155 CN2280917Y (en) | 1996-06-24 | 1996-06-24 | Digital insulation resistance meter |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN2280917Y true CN2280917Y (en) | 1998-05-06 |
Family
ID=33911301
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 96235155 Expired - Fee Related CN2280917Y (en) | 1996-06-24 | 1996-06-24 | Digital insulation resistance meter |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN2280917Y (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103792430A (en) * | 2012-10-26 | 2014-05-14 | 无锡华润上华科技有限公司 | Self-adaptive range resistance test method |
-
1996
- 1996-06-24 CN CN 96235155 patent/CN2280917Y/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103792430A (en) * | 2012-10-26 | 2014-05-14 | 无锡华润上华科技有限公司 | Self-adaptive range resistance test method |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C19 | Lapse of patent right due to non-payment of the annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |