CN2075787U - Digital display tramegger for absorptance - Google Patents

Abstract

The utility model provides a digital display megohmmeter for absorptance, which can test the insulation properties of various motors, cables, transformers, domestic appliances and other low-voltage electric apparatuses. The megohmmeter of the utility model is formed by that the low-voltage direct current is converted into a high-voltage DC power supply to be connected with a standard sampling resistor (15) in series; the megohmmeter of the utility model is provided with range control switches (16, 19), decoding and displaying devices (17, 16, 20, 21), etc. The utility model has the advantages of digitization, intellectualization, convenient operation, high precision, clarity, direct viewing, etc., and thus the utility model can replace the present hand-operated pointer-type megohm testing instrument.

Description

Digital display tramegger for absorptance

The utility model will provide a kind of numeral demonstration absorptance megohmmeter that various low-voltage electrical apparatus insulating property are used of testing.

At present, existing various megger test megohmmeters all mean pin type, and the constant voltage source of megohmmeter all uses hand motor to supply with.Because the testing power supply that hand motor is supplied with is disturbed by the speed of hand motor, so that the measuring accuracy actual error is bigger, often greater than 10% of pointer value.Influence test measure of precision, and have that volume is big, Heavy Weight, use shortcomings such as inconvenience.

The utility model is intended a kind of direct employing low-voltage dc power supply is provided, and is high voltage direct current through the inversion rectification, a kind of novel megaohm test instrumentation that test gained insulation values shows with liquid crystal display three bit digital.

In order to achieve the above object, the technical scheme that the novel plan of this reality adopts is: by one is a polyphone standard sample resistance (15) in 1 ohm the measurement loop of high-voltage DC power supply as the 1000V internal resistance of measuring power supply, two ends at standard sample resistance (15) receive a range control switch (16,19) and decoding that the electric current of being gathered reflects tested insulant resistance value, display device (17,16,20,21) together.Range control switch (17,16,20,21) is that 8031 systems (16) that 8031,373,2,716 three integrated packages are formed connect OP-07 integrated package (19).Its decoding, display device is by MC14433 integrated package (17), 2716 integrated packages (16), through 8031,373,2,716 three integrated packages of 8031 systems (16), be presented at LCD plate (22) to the apparent sign indicating number device of forming by 4040,4054,4055 * 3 five integrated packages (21) and constituted again.

Advantage of the present utility model: (1) gets rid of hand motor and magnetoelectricity series measuring mechanism, can save more valuable metal materials such as a large amount of copper; (2) measuring accuracy height, almost error free; (3) adopt liquid crystal digital to show to have advantages such as clear and intuitive.

Fig. 1--numeral shows the outside drawing of absorptance megohmmeter.

Fig. 2--numeral shows the stable high-pressure direct supply figure of absorptance megohmmeter.

The principle of work block diagram of parts such as the measurement of Fig. 3--numeral demonstration absorptance megohmmeter, decoding, demonstration.

Fig. 4--numeral shows the measurement of absorptance megohmmeter, the circuit diagram of decoded portion.

Fig. 5--numeral shows the apparent sign indicating number device circuit diagram of absorptance megohmmeter.

Below in conjunction with accompanying drawing, the utility model is described further with embodiment.

Numeral shows profile such as Fig. 1 of absorptance megohmmeter, and first a row left side, surface is that L binding post (1), centre are G binding post (2), and the right side is E binding post (3); The second behavior LCDs (4); The third line is as the red light of time marker--15 seconds (7), green light--60 seconds (6), amber light--10 minutes (5); The fourth line left side is power switch (9), and the right side is data maintained switch (10).Power unit in the megohmmeter is the high pressure generator as Fig. 2, should produce the high voltage direct current source that a 1000V has 1 milliohm internal resistance.For this reason, at first 12V direct current (being supplied with by No. 5 heavy-duty batteries of 8 joints or No. 5 ickel-cadmium cells) is become alternating current through voltage stabilizing part (10) to oscillating part (11), boost part (12) to the 1000V alternating current through transformer again, at last again through high-voltage rectifying part (13) high-voltage DC power supply output (14).By standard sample resistance of polyphone in this high voltage direct current resource loop, standard sample resistance (15) one ends extremely are connected with another utmost point E binding post (3) with the other end with L binding post (1) with one of high-voltage DC power supply.The same measurement of standard sample resistance (15) two ends in the machine, decoding, display circuit (consulting Fig. 3,4) connect.Because the scope of this table measurement insulation resistance value is the 0-1000 milliohm, so the sampling voltage scope on the standard sample resistance (15) should be 2mV-2000mV, in order to cause the measured object low-voltage and when improving its measuring accuracy, low-voltage need to be given to amplify when resistance value is higher.For this reason, see also Fig. 3,4, to constitute 8031 systems (16) via OP-07 integrated package of using as operational amplifier (19) and 8031,373,2,716 three integrated packages of making the range single-chip microcomputer without the electric signal that amplifies earlier and differentiate, control electronic switch (19), be divided into two sections of 2mV-50mV and 50mV-2000mV.To 50mV-2000mV do not amplify for one section directly enter three and half analog/digital MC14433 integrated packages (17) but and stored that 2716 integrated packages (16) that translation procedure uses detect, computing, again through code translator 373 integrated packages (16), by output/input (I/O) interface 8155 integrated packages (20), the apparent sign indicating number device (21) that is made of 4040,4054,4055 * 3 five integrated packages as Fig. 5 is encoded and is gone up its resistance value of demonstration in LCD plate (22) again.One section of 2mV-50mV low pressure still needed after OP-07 integrated package (19) amplifies signal, enter earlier three integrated packages of three and half analog/digital MC14433 integrated packages (17) and 8031 systems (16) again, after testing, the signal after the computing enters apparent sign indicating number device (21) coding that is made of five integrated packages (Fig. 5) of 4040,4054,4055 * 3 and goes up in LCD plate (22) through 8155 integrated packages (20) of output/input (I/O) interface again and shows resistance value.

This numeral shows that the response time of absorptance megohmmeter reading is 3 seconds.At first, be connected to L binding post (1) and E binding post (3) that numeral shows the absorptance megohmmeter,, then shell or earth terminal should be connected to E earthing rod (3) if the shell of tested insulant needs ground connection or earth terminal is arranged with the two poles of the earth of tested insulant.Measure if tested insulant need be done shielding, then screening electrode is connected to G binding post (2).Then, power-on switch (9) makes display screen (4) operate as normal.The shown value of display screen (4) is the resistance value of tested insulant.Measured 60 seconds and 15 seconds absorptances (the insulation resistance ratio that refers to 60 seconds and 15 seconds) as need.When surperficial red light (7) was bright, the reading when writing down this was 15 seconds insulation values.Then, treat to write down when green light (6) is bright again the insulation values that at that time reading was 60 seconds, the two ratio was 15 seconds: 60 seconds absorptance.Measure the absorptance of 10 minutes same minute (60 seconds) if desired.Only need treat to write down when amber light (5) is bright the insulation values that this reading is 10 minutes, compare with 60 seconds again and be 60 seconds: 10 minutes absorptance.Keep the insulation values that certain moment surveys if desired, press data maintained switch (8) and get final product.Measure and finish powered-down switch (9).

The application's case utility model has been produced model machine number, and is on probation through relevant department, and generally reflection thinks that measuring accuracy is higher, and is easy to carry, can be used as the regeneration product of hand megohmmeter.

Claims (3)

1, a kind of numeral of using for test low-voltage electrical apparatus insulation performance shows the absorptance megohmmeter, its feature is a polyphone standard sample resistance (15) in the measurement loop of high-voltage DC power supply of 1 milliohm as the 1000V internal resistance of measuring power supply by one, two ends at standard sample resistance (15) receive a range control switch (16,19) and decoding that the electric current of being gathered can reflect tested insulating resistance value together, and display device (17,16,20,21) constitutes.

2, numeral as claimed in claim 1 shows the absorptance megohmmeter, it is characterized in that 8031 systems (16) the connection OP-07 integrated packages (19) that range control switch is made up of 8031,373,2,716 three integrated packages are constituted.

3, numeral as claimed in claim 1 shows the absorptance megohmmeter, it is characterized in that 8031,373,2,716 three integrated packages (20) that decoding, display device pass through 8031 systems (16) by MC14433 integrated package (17) and 2716 integrated packages (16) through 8155 integrated packages, be presented at LCD plate (22) again via 4040,4054,4055 * 3 five integrated packages again and constitute.

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