BS EN 62058-21-2010 pdf download.Electricity metering equipment (a.c.) Acceptance inspection Part 21: Particular requirements for electromechanical meters for active energy (classes 0,5, 1 and 2 and class indexes A and B).
If, for the different tests, the sampling plans give different sample sizes, then the number of samples shall be equal to the largest sample size. The smaller sample shall be chosen from the larger sample randomly.
I See also EN 62058-11, 5.5.
5.2 Preliminary tests and pro-conditioning
The meters selected for inspection shall be visually examined in order to verify that they belong to the same type, that their specified markings are correct and that none of them shows signs of damage. The meters shall be in conformity with the type approval and they shall have the same voltage and current charactesristics.
Before the tests, the meters shall be energized at reference voltage and loaded with the current specified below, at unity power factor, to reach thermal stability.
The value of the current shall be 0,1 ‘b for direct connected meters or 0,1 I for transformer operated meters respectively.
The tests shall be performed In the order below.
[0 For meters of class indexes A and B, the value of the current shall be 4. (J
5.3 Test No. 1: AC voltage test
The ac. voltage test shall be carried out in accordance with Table 5.
The test voltage shall be substantially sinusoidal, having a frequency between 45 Hz and
65 Hz, and applied for 2 s. The power source shall be capable of supplying at least 500 VA.
The rise time and the fall time of the test voltage shall be S 2 s. The auxiliary circuits with
reference voltage equal to or below 40 V shall be connected Lu earth.
During this test, no flashover. disruptive discharge or puncture shall occur.
As the values of e(I, cosq). taken from Table U are smaller than the values e (I, cosg) calculated from the MPE taking into account the values of vanation of percentage error due to temperature, voltage and frequency variation, established during type testing, the values e(I, cosp) of Table U shall be used.
If the meter is intended foc a wider temperature range, then the calculation has to be performed for each temperature range, and the smaflest percentage error limits — out of all the calculated values (I, cosç,) and the values e(l, cos) of Table U — shall be used. I
5.7 Test No. 10: VerIfication of the register
This test shall be performed by measuring a sufficient amount of energy, to verify that the accuracy of incrementing the register reading is better than ±1.0 %.
The test shall be done for each meter on at least one tariff register.
5.8 Other tests
The manufacturer and the customer may agree to perform testing of any additional functionality and mechanical aspects.
The inspection methods — 100 % testing, Inspection by attributes or inspection by variables — and the acceptance conditions shall be agreed by the manufacturer and the customer.
Some examples for mechanical testing are given below:
• meshing of the register;
• soldered and welded seams;
• tightness of screws;
• swarf. filings and metal dust especially in the air-gap(s) of the brake magnet(s):
• any other item which is deemed desirable.
6 Criteria for lot acceptance non-acceptance, disposal of unacceptable lots See IEC 62058-11, 5.18 and the relevant clauses for each inspection scheme.
7 Test record and evaluation
The test results of the sample shall be recorded and evaluated In the inspection sheet given in Table 8 below
NOTE Tests agreed between the manufacturer arid the purchaser may be added
For larger sample sizes, several inspection sheets may be necessary. The results shall be evaluated on the last sheet In this case, in the line “ResuW’ write “Continued on next inspection sheer. The cell “Lot number” can be used for numbering the inspection sheets including test results of a lot.
For double sampling plans, two sets of inspection sheets may be necessary.BS EN 62058-21-2010 pdf download.

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