GB/T 3925-1983 Acceptance method for class 2.0 AC watt-hour meter GB/T3925-1983 standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Acceptance inspection of class 2 alternating-current watthor metersUDC621:317.78
:621-78
GB 3925-83
This standard applies to the acceptance inspection of class 2 induction system alternating-current active watthor meters with a rated frequency of 50Hz, which are mass-produced and supplied in batches according to GB3924--83 "AC active and photoelectric active watthor meters". This standard specifies two methods: 100% inspection and sampling inspection. 1 Definition
1.1 Batch
A certain number of meters with the same voltage, the same current calibration value, the same meter, the same model and the same specification delivered for acceptance by a supplier.
1.2 Batch range
Batch rate The number of meters N.
1.3 Samples
Instruments taken randomly from the batch for inspection. 1.4 Sample range
Number of samples n.
1.5100% inspection
All instruments in the batch are inspected.
1.6 Sampling inspection
Inspection of a limited number of instruments randomly selected from the batch according to a specified sampling plan. 1.7 Sampling plan
A plan according to which a certain number of samples are drawn to obtain data and reach a judgment. 1.8 Characteristics (quality characteristics)
This is the difference in quality performance (e.g. insulation, starting, accuracy of a test) between instruments in a given batch. This difference can be quantitative (inspected by quantity) or qualitative (inspected by quality). If the characteristic is measurable, the value of the first table is expressed as. 1.9 Unqualified
Failed to meet the requirements of the relevant characteristic standards. 1.10 Unqualified instrument
An instrument with one or more unqualified items.
1.11 Working characteristic curve
According to the specified sampling plan, the curve that shows the probability of batch acceptance as a function of the actual quality of a given characteristic. 1.12 Quality inspection
Used to inspect certain qualities of the sample instrument being evaluated, classified according to whether it meets or does not meet the requirements, and the number of unqualified instruments is calculated and used as the basis for judging the batch.
1.13 Acceptance number
The maximum number of unqualified instruments allowed in the sample for quality inspection. National Standard Issued on 1983-11-08
Implementation on 1984-10-01
1.14 Inspection by quantity
GB 3925-83
Inspect the continuous quantity values ​​(e.g. expressed as percentages) of certain characteristics that can be measured by the instrument (e.g. instrument error for a specified load), calculate their mean value, standard deviation or average range, and use it as the basis for judging the batch. 1.15 Sample inverse mean
The arithmetic mean of the sample characteristics (e.g. instrument error for a specified load). n
1.16 Range w
The absolute value of the difference between the maximum and minimum measured values ​​of a given characteristic in a sample group, the i-th group is: j = imax-xmin
1.17 Average range
The average value of the r ranges w; of the r groups in the sample. w
1.18 Standard deviation of samples
Estimated value of the deviation of batch characteristics:
Acceptance trapezoid
A graph with control limits, in which two corresponding statistical values ​​(i.e., sample mean and standard deviation s or average range) can be found for each sample.
1.20 Acceptance quality level
The maximum percentage of unqualified instruments allowed in a batch for a specified characteristic. 2 Classification
2.1 Acceptance inspection methods are divided into:
a. 100% inspection
b. Sampling inspection.
2.2 Sampling inspection is based on the principles of mathematical statistics. Therefore, both the manufacturer and the buyer have to accept certain risks. However, sampling inspection is generally more economical than 100% inspection.
In fact, for the evaluation of instrument batch quality, the results of sampling inspection and 100% inspection are close to the same. 2.3 Sampling inspection is expressed in two ways.
2.3.1 Quality inspection
Applicable to the measurable characteristics whose characteristics are unmeasurable and non-normally distributed, and can also replace the quantitative inspection method of normal distribution. 2.3.2 Quantitative inspection
Applicable only to the characteristic values ​​whose values ​​are measurable and approximately normally distributed. The above two methods are substantially equivalent for the quality of the products. 3 Batch acceptance conditions
3.1 Batch composition
GB 3925-83
501000 instruments are considered as a batch. If there are more than 1000 instruments, they can be divided into batches of 500 to 1000 instruments accordingly. 3.2 Batch acceptance conditions
3.2.1 If the proportion of unqualified instruments for each accepted characteristic does not exceed the following specified values, it is believed that the batch meets the requirements of this standard and should be accepted. Instruments with qualified constants and insulation will not be accepted. 3.2.1.1 Add 0.001/current, the meter with one full turn of the turntable should not exceed 1%, Ib is the calibration current. Add 0.006Ib current, the meter with one full turn of the turntable should not exceed 1%; 3.2.1.2
The meter with error exceeding the specified limit at each test point (Table 2) should not exceed 1%; 3.2.1.34
3.2.2 To meet the above conditions, in the sample inspection, each characteristic of the meter in the batch must meet the following requirements: 3.2.2.1 The number of unqualified meters in the quality inspection is less than or equal to the number of meters allowed for acceptance. 3.2.2.2 The test results shown in the diagram in the quantity inspection should be within the acceptance trapezoid, and the calculated test results should not exceed the specified limit. Inspection location
Determined by mutual consultation, the inspection shall be carried out on the following test benches: 4.1 On the test bench of the manufacturer!
4.2 On the test bench of the purchaser;
4.3 On other test benches agreed upon by the cabinets. 5 Test conditions
5.1 Rated conditions
The test shall be carried out according to the conditions specified in Table 1.
Ambient temperature
Position*
Voltage**
Voltage and current waveforms
External magnetic field
Rated conditions
Rated voltage
Rated frequency
5.2 The total permissible error limit of the test device used for the test shall comply with the following specified values: cosp = 1
5.3 Meter and seal
*In the following cases:
a The bottom of the meter is mounted on a vertical wall;
b. The reference edge (such as the bottom of the terminal block) and the horizontal reference line marked on the instrument housing, the design and assembly of the meter should ensure that the instrument is vertical (front and back left and right parts are on the vertical plane). * *For three-phase receiving meters
The difference between the voltage of each phase or line and the corresponding voltage average value is not greater than 1. The difference between the current and the lower average current of each phase or line is not greater than 2. Allowable deviation
±3℃
Distortion coefficient <5%
Instrument has geomagnetic field
The phase shift of each phase cross current to the phase of the corresponding electric jade, without considering the power factor, the difference between the phase points is not more than 3" GB3925-83
The instrument should be tested under the condition of removing the cover and not damaging the production seal, except for the mechanical characteristics. 6 Inspection and test procedures
On the measuring instrument The quality of the meter shall be tested and inspected according to the following inspection and test procedures. 6.1 Pre-inspection and preheating conditions
6.1.1 The meter under test shall be visually inspected to be full of tightness. No signs of damage:
b. The markings of the gauges shall be correct.
6.1.2 The meter shall be connected to the rated voltage and 0.111, cosΦ=1 and powered on for at least 30 minutes to check the rotation of the turntable and preheat the meter. 6.1.3 For 100% inspection, any - - The meters that may be replaced shall be determined by negotiation between the manufacturer and the purchaser. 6.1.4 For sampling inspection, one meter is allowed to be replaced in 30 samples and two meters are allowed to be replaced in 40 samples. 6.1.5 All meters that meet the above requirements shall be tested according to the items and sequence specified in 6.2. With the agreement between the manufacturer and the purchaser, the test procedures specified in 6.2 may not be followed, except for the test. 6.2 Test items
6.2.1 Insulation test (test number: 1)
The insulation test between the interconnecting terminals of the meter and the casing or between the exposed metal parts of the insulating casing shall be able to withstand a 50Hz solid sine wave 2kV test voltage for 1 minute. 6.2.2 Creep (test number: 2)
When the meter is connected to the rated voltage, 0.0011b and c0s9=1 and wired according to the wiring diagram, the turntable should not rotate more than one full turn. 6.2.3 Start (Test No.: 3)
When the meter is connected to the rated voltage, 0.0061 and cosg = 1, the meter dial rotates continuously. 6.2.4 Accuracy (Test No.: 4 to 9) The accuracy test is carried out in accordance with Table 2. It is not required to wait for thermal equilibrium to be reached. Table 2 Test points and error limits
Test number
I rmax
Power factor
Instrument number
Single phase and three phase
Single cabinet and three phase
Single handle and three phase
Single phase or three phase
6.2.5 Instrument constant test (test number: 10) Three-phase balanced or unbalanced
Three-phase load
Three-phase load (test difference with 57)
Rotate the circle an integer number of revolutions and read the reading of the drum or pointer of the counter to verify the instrument constants. 6.2.6 Machine inspection (test number: 11)
Error spread
Without considering the batch range, take 5 instruments from 100 end inspections or from the samples of sampling inspections by machine mode, open the shell and conduct inspection (for secondary sampling, it should be taken from the first sample). Open the shell and conduct inspection:
1) Measuring device engagement,
2) Connection quality:
3) Nail tightening:
GB 3925--83
1) Metal shavings, debris, especially metal powder in the gap of brake magnet, 5) Other items,
Acceptance procedure
Acceptance method shall be carried out according to the 100% inspection and sampling inspection method agreed by both parties. Except for test 11. 7.1 100% inspection || tt || 7.1.1 Acceptance quantity C (number of unqualified instruments) The instrument batch should comply with all test requirements in Chapter 6. The number of unqualified instruments in each test should not exceed the C value specified in Table 311. Table 3 Batch and corresponding acceptance quantity
30 -149
150 ~ 219
250 ~349
350 ~449
450~549
550 ~649
650-749
730849
850~949
950~1000
7.1,2 Processing procedures for unqualified instruments!
1) If the acceptance conditions are met, the unqualified instruments shall be repaired or replaced with instruments that meet all the conditions. 2) If the acceptance conditions are not met,
the acceptance quantity exceeds the limit,
a section of the instrument test fails,
the instrument test question 1 test is not complete.
The above results shall be agreed between the manufacturer and the purchaser. In particular, instruments that fail test 1 and (or) 10 are required to be inspected again.
7.2 Sweep Sample Inspection
The risk of the purchaser accepting low-quality instruments and the risk of the manufacturer rejecting substandard instruments shall be considered when sampling for sweep sample inspection. 7.2.1 Sweep Sample Inspection Procedure
7.2.1.1 Selection of Samples
In batches of only 100 instruments, the sample range determines the inspection quality level (A,) and the manufacturing risk α. AQ = 1%, α = 5 to 10 (test numbers: 2 to 9) 4QI. = 0.2*, α - 3.8% (test numbers: 1 to 10) The oil fence scheme is valid for batches A from 50 to 1000 (inclusive) instruments. If the number of instruments exceeds 1,000, the instruments can be divided into batches of 500 or 1,000.
For random sampling, random numbers can be used or a more suitable random selection method can be used. Example of using a random number table according to Table 4:
GB 3925-83
1) The batch sequence numbers of adjacent non-columns are from 100 to 330; 2) Select the three columns, for example: 1st, 11th and 21st columns, from the 6th row to the 15th row, and get the three digits from the intersection of the row and column order.
For example, the three digits selected are as follows: Random numbers
Random numbers
Those with * are random numbers for batch serial numbers. This number is the selected sample instrument number. The random numbers repeated and exceeding the batch serial number are not valid. 1
22 17 68 65 84
1936275946
1677230277
78 43 75 71 61
0328 2826 08
98 22 58 84 39 | |tt | 48 95 03
36 93 89 41 26
1887004231
88 56 53 27 59
0972958129
12 96 88 17 31
$5 94 57 24 16
38 64 43 59 98
53 44 09 42 72
4076662684
02 17 79 18 06
95 17 82 06 63
3576224292
26 29 13 56 41
77 80 20 75 82
46408644.52
37 56 08 18 09
61 65 61 68 66
934369 64 07
2196601299
95 20 47 97 97
97 86 21 78 73
6992063413
(04 31 17 21 56
6106980391
8593858688
21 74 3247 45 | | tt | 64 | |tt | | 73 37 32 04 05 | 34 27
24 53 63 91 09 | |tt | | 3206347252 | 70 | |tt | 02
31 51 10 96 46
9611.8 44 www.bzxz.net
8547046608
72 82 32 9990
91 36 74 43 53
77 53 84 46 47
37 27 47 39 19||tt ||34 18 04 52 35
11 20 99 45 18
27 3783 28 71
10 65 81 92 59
59 71 74 19 32
33 73 0919 87| |tt||87 14 77 43 96
72 87 08 62 40
7396079452
7996235310
Random number table
87 02 22 57 51
6109439506
3977327709||tt| |28 06 24 25 93
97 67 63 99 61
69 301609 05
8703047988
52 06 79 79 45
52704834
1533500528
85 13 99 24 44 | |tt | |77 34 55 45 70 | | tt | | 4238064518 | | tt | twenty two 07904703
9206880777
3468 3548 77
3472575913
7282329990
3082135400
31 91 18 95 68
84 83 70 07 48
56 27 09 24 86
48 13 93 55 34
0006414374
58 76 17 14 97
2755102419
26 72 39 27 67
43 00 65 98 50
16 06 10 89 20
09 65 90 77 47
6539071629
8552053062
16 7113 69 78
4638039322
69682899
0% 13 13 85 51
82 63 18 27 44
56 65 05 61 86
22 87 26 07 47
49 18 (979 49
44 04 95 49 66
33 29 94 71 11
77 21 30 27 12
87 09 41 15 09
5408918863||tt ||08 12 27 38 90
64 84 73 38 65
24 64 19 35 51
29 81 94 78 70
40 98 05 93 78
35 65 31 51 51
37 40 13 68 97
28 14 11 30 79
56 11 50 81 69
3342409060
8243804615
6395737663
784563835
24 16 74 11 53
53 21 40 06 71
61 85 53 83 45
1837794990
4589093984
04 76 62 16 17
23 71 82 13 74
53 77 57 68 93
45 60 33 01 07
23 21 31 74 97
25 76 16 19 33
45 33 02 44 70
58 24 82 09 47
4783516274
23 05 47 47 25
69 1 21 9921
35 07 44 75 47
56 34 57 72 69||tt| |69 66 92 19 09
90 92 10 70 80
86 96 9829 06
7416322302
39 80045981
15 91.29.12 93
90492223 62
9860160303
3941889210
16 95 86 70 75
52 53 37 97 15
5661878912
21 94 47 90 12
23 32 65 41 18
0083632265
87 64 81 07 83
20 69 22 40 98
40 23 72 61 39
73 96 53 97 86
38 26 61 70 04
48 67 26 43 18
5503366768
44 10 13 85 57
95 06 79 88 54
19 90 70 99 00
6597382046
51 67 11 52 49
17 95 70 45 80
63 52 52 01 41
60 61 97 22 61
98 99 46 50 47
76 38 03 29 63
53 05 70 53 30
0287404145
The sample range n should be inspected.
7.2.1.2 Sample plan
The sample plan is shown in Table 5:
GB $925--83
Sampling plan table
According to quality inspection Sample batch range
Test number
Test type
Insulation test
Accuracy*
Number of instruments
101≤ N≤500
nicild, na
501na
501na
501na
501na
50112 93
90492223 62
9860160303
3941889210
16 95 86 70 75
52 53 37 97 15
5661878912
21 94 47 90 12
23 32 65 41 18
0083632265
87 64 81 07 83
20 69 22 40 98
40 23 72 61 39
73 96 53 97 86
38 26 61 70 04
48 67 26 43 18
5503366768
44 10 13 85 57
95 06 79 88 54||tt ||19 90 70 99 00
6597382046
51 67 11 52 49
17 95 70 45 80
63 52 52 01 41
60 61 97 22 61||tt ||98 99 46 50 47
76 38 03 29 63
53 05 70 53 30
0287404145
The sample range n should be inspected.
7.2.1.2 Sample plan
The sample plan is as shown in the table 5:
GB $925--83
Sampling plan table
Batch range of quality inspection sampling plan
Test number
Test type
Insulation test
Accuracy*
Number of instruments
101≤N≤500
nicild, na
50112 93
90492223 62
9860160303
3941889210
16 95 86 70 75
52 53 37 97 15
5661878912
21 94 47 90 12
23 32 65 41 18
0083632265
87 64 81 07 83
20 69 22 40 98
40 23 72 61 39
73 96 53 97 86
38 26 61 70 04
48 67 26 43 18
5503366768
44 10 13 85 57
95 06 79 88 54||tt ||19 90 70 99 00
6597382046
51 67 11 52 49
17 95 70 45 80
63 52 52 01 41
60 61 97 22 61||tt ||98 99 46 50 47
76 38 03 29 63
53 05 70 53 30
0287404145
The sample range n should be inspected.
7.2.1.2 Sample plan
The sample plan is as shown in the table 5:
GB $925--83
Sampling plan table
Batch range of quality inspection sampling plan
Test number
Test type
Insulation test
Accuracy*
Number of instruments
101≤N≤500
nicild, na
501
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