EN 60514:1995
(Main)Acceptance inspection of Class 2 alternating-current watthour meters
Acceptance inspection of Class 2 alternating-current watthour meters
Methods for acceptance inspection (100% inspection and statistical sampling inspection) and testing of newly manufactured direct connected induction type watthour meters of Class 2 which are produced and delivered in large quantities. For type tests see EN 60521. This publication has the status of a report.
Annahmeprüfung von Wechselstrom-Wirkverbrauchzählern der Klasse 2
Contrôle de réception des compteurs à courant alternatif de la classe 2
Méthodes pour les essais et contrôles de réception (à 100% et par échantillonnage) des compteurs à induction, neufs, à branchement direct, fabriqués et livrés en grandes quantités. Pour les essais de type, utiliser la EN 60521. Cette publication a le statut d'un rapport.
Prevzemna kontrola za števce električne delovne energije izmeničnega toka razreda 2
General Information
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Standards Content (Sample)
SLOVENSKI STANDARD
01-avgust-1995
3UHY]HPQDNRQWUROD]DãWHYFHHOHNWULþQHGHORYQHHQHUJLMHL]PHQLþQHJDWRND
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Acceptance inspection of Class 2 alternating-current watthour meters
Annahmeprüfung von Wechselstrom-Wirkverbrauchzählern der Klasse 2
Contrôle de réception des compteurs à courant alternatif de la classe 2
Ta slovenski standard je istoveten z: EN 60514:1995
ICS:
17.220.20 0HUMHQMHHOHNWULþQLKLQ Measurement of electrical
PDJQHWQLKYHOLþLQ and magnetic quantities
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
RAPPORT
CEI
TECHNIQUE IEC
TECHNICAL
Première édition
REPORT
First edition
Contrôle de réception des compteurs
à courant alternatif de la classe 2
Acceptance inspection of Class 2
alternating-current watthour meters
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– 3 –
CONTENTS
Page
FOREWORD 5
PREFACE 5
INTRODUCTION 7
Clause
1. Scope 7
2. General remarks 7
3. Units 9
4. Definitions 9
Acceptance conditions for batches 5.
6. Place of inspection
7.- Test conditions
7.1 Reference conditions
7.2 Uncertainty of measurement
7.3 Cover and seal
8. Inspection and test procedure
8.1 Preliminary tests and pre-conditioning 17
8.2 Test No. 1: dielectric properties 17
17 8.3 Test No. 2: running with no-load
8.4 Test No. 3: starting
8.5 Tests Nos. 4 to 9: accuracy
8.6 Test No. 10: verification of meter constant
8.7 Test No. 11: mechanical inspection
9. Requirements corresponding to different inspection procedures
9.1 100% inspection
9.2 Sampling inspection
Tables
I. Reference conditions
II. Test points and limits of errors
III. Acceptance number c
IV. Random numbers
Sampling plans 25
V.
VI. Double sampling plan
VII. Specified values for the standard deviation method
VIII. Specified values for the average range method
IXa. Operating characteristic curves N , 100 36
IXb. Operating characteristic curves 101 N= 500
IXc. Operating characteristic curves 501 ENE 1 000
X. Inspection sheet
XIa. Acceptance trapezium, T = 3.5%
XIb. Acceptance trapezium, T = 3.0%
XIc. Acceptance trapezium, T = 2.5% 42
A – Explanatory notes concerning sampling procedures for Class 2 watthour meters 45
APPENDIX
APPENDIX B – Symbols
— 5 —
INTERNATIONAL ELECTROTECHNICAL COMMISSION
ACCEPTANCE INSPECTION OF CLASS 2 ALTERNATING-CURRENT
WATTHOUR METERS
FOREWORD
1) The formal decisions or agreements of the IEC on technical matters, prepared by Technical Committees on which all the National
Committees having a special interest therein are represented, express, as nearly as possible, an international consensus of opinion on
the subjects dealt with.
2) They have the form of recommendations for international use and they are accepted by the National Committees in that sense.
3) In order to promote international unification, the IEC expresses the wish that all National Committees should adopt the text of the
IEC recommendation for their national rules in so far as national conditions will permit. Any divergence between the IEC recommen-
dation and the corresponding national rules should, as far as possible, be clearly indicated in the latter.
PREFACE
This report has been prepared by Sub-Committee 13A, Integrating Meters, of IEC Technical Committee
No. 13, Measuring Instruments.
Drafts were discussed at the meetings held in Budapest in 1970, in S tresa in 1971 and in Toronto in 1972.
As a result of this latter meeting, a draft, document 13A(Central Office)35, was submitted to the National
Committees for approval under the S ix Months' Rule in July 1973.
The following countries voted explicitly in favour of publication:
Argentina Italy
Austria Netherlands
Belgium Poland
Denmark Portugal
South Africa (Republic of)
Egypt
France Sweden
Germany Switzerland
Hungary Turkey
India Yugoslavia
Israel
–.7 –
ACCEPTANCE INSPECTION OF CLASS 2 ALTERNATING-CURRENT
WATTHOUR METERS
INTRODUCTION
1) It is emphasized that this publication is a report and does not constitute either a standard or a specifi-
cation.
This report describes, in some detail, methods for acceptance inspection, and testing of newly manufactured
watthour meters of Class 2 delivered in large quantities.
In this report wider error limits than those for type tests specified in the relevant publications have been
allowed because:
– acceptance testing conditions have wider tolerances than those for type tests;
– displacing of the zero axis is not applicable for acceptance testing;
– the effects of handling of meters are taken into account.
2) This report has been issued with the object of enabling experience to be gained with meter acceptance
testing methods (100% inspection and statistical sampling inspection). The intention is that the contents will be
reviewed and the explanatory Appendix A deleted. In addition, the question of changing the status of this
publication from a report to a standard will then be considered.
With these objects in view, the comments of National Committees are invited in three years' time.
Scope
1.
The methods and procedures included in this report apply to newly manufactured direct connected induction
I E C Publication* 521, which are produced and delivered in large
type watthour meters of Class 2, covered by
quantities.
They provide for 100% inspection or sampling inspection for acceptance by the purchaser.
2. General remarks
2.1 Two methods of acceptance inspection are proposed, namely:
– 100% inspection, and
– sampling inspection.
2.2 The 100% inspection consists of testing all the meters of a batch.
2.3 The sampling inspection is based upon the principles of mathematical statistics and as a consequence
certain specified risks are undertaken both by the manufacturer and the purchaser. However, sampling inspec-
tion generally is more economical than 100% inspection.
In this report sampling inspection has been planned so that, in practice, the quality of the meter batches can be
judged with nearly the same accuracy as with 100% inspection.
2.4 Two methods of sampling inspection are described:
– inspection by attributes;
– inspection by variables.
These two methods have been chosen so that the judgement of quality is virtually the same for both methods.
2.5 Inspection by gives results indicating conformity or non-conformity.
attributes
It shall be applied when the characteristic under inspection cannot be measured.
It shall also be applied when a characteristic can be measured but the values are not of normal distribution
(Laplace-Gauss).
It
may be applied, when the distribution is approximately normal, in place of inspection by variables.
The advantage of inspection by attributes is its simplicity of application.
* Class 0.5, 1 and 2 alternating-current watthour meters (being printed).
– 9 –
gives additional information but it is applicable only when the values of a
2.6 Inspection by variables
characteristic are measurable and when those values are approximately normally distributed. In these circum-
stances, inspection by variables is the recommended method.
The advantage of inspection by variables is a smaller sample size than by attributes for the same risk of
decision. However, it requires more calculation.
The test results are represented by:
x = the sample mean as an estimation of the batch mean;
s = the
in the batch.
standard deviation l as an estimation of the dispersion of the characteristic x
w = the average range J
average range is easier to calculate than the standard deviation. However, when suitable calculating means are available for
Note. -The
making a decision and for preparing additional information, the use of the standard deviation enables the efficiency of the method
to be increased for the same sample size.
3. Units
The units employed in this report are those used by the IEC.
4. Definitions
For definitions concerning meters, reference is made to IEC Publication 521. The majority of the defi-
nitions of sampling techniques are generally in accordance with the Glossary (1972) of the European Organiz-
1786 (1970)*, Statistical
645 (1967) and ISO/R
ISO/R
ation for Quality Control (E.O.Q.C.) and with
Vocabulary and Symbols.
Batch
4.1
A definite quantity of meters of the same type, of the same voltage and current rating and the same register,
delivered by one supplier, manufactured or produced under conditions which are presumed uniform.
4.2 Batch size
The number N of meters in a batch (ISO).
4.3 Sample
Meters taken at random for inspection from a batch.
4.4
Sample size
The number n of meters in the sample (ISO).
4.5 100% inspection
Inspection of every meter in a batch.
4.6 Sampling inspection
The inspection of a limited number of meters, taken at random from the batch, according to a prescribed
sampling plan (ISO mod.).
4.7 Sampling plan
A plan according to which one or more samples are taken to obtain information and possibly to reach a
decision (ISO).
* It is intended to take the corresponding definitions of IEC Publication 410 (1973), Sampling Plans and Procedures for Inspection by
Attributes, into consideration in the future.
– 11 –
4.8 Characteristic (quality characteristic)
A property (e.g. dielectric strength, starting, accuracy at one test point) of a meter which contributes to the
quality and which helps to differentiate between the meters of a given batch. The differentiation may be either
quantitative (by va
riables) or qualitative (by attributes).
If it is measurable, its value for a given meter i is indicated by x, (ISO mod.).
4.9
Defect
A failure of a meter to meet a standard with respect to a characteristic (ISO mod.).
4.10
Defective meter
A meter having one or more defects (ISO mod.).
4.11
Operating characteristic curve
A curve showing, for a given sampling plan, the probability of acceptance of a batch as a function of its
actual quality for a given characteristic (ISO mod.).
4.12 Inspection by attributes
Inspection whereby certain characteristics of the sample meters are evaluated, classified as conforming or
not conforming to the requirements, the number of defective meters counted and used as the basis for
judgement of the batch (E.O.Q.C.).
4.13 Acceptance number
The maximum permitted number of defects in a sample for inspection by attributes.
4.14 Inspection by variables
Inspection whereby certain characteristics of the sample meters (e.g. a meter error for a particular current)
are measured with respect to a continuous scale (e.g. in per cent), and their mean value, the standard deviation
or the average range calculated and used as the basis for judgement of the batch.
4.15 Sample mean x
The arithmetic mean of values for a characteristic (e.g. a meter error for a particular current) in the
sample:
X,
i 1
=
X =
n
4.16. Range wj
The difference between the maximum and minimum observed values of a given characteristic in a sub-
group: *
wj Xmax — Xmin
for sub-group j.
4.17
Average range )7,7**
The arithmetic mean of the r ranges wj of the r sub-groups in a sample:
r
wj
j= 1
w =
* For the purpose of this report, the size m r sub-groups in a sample.
of a sub-group j is 5 and there are
** This is an estimation of the dispersion of the characteristic x in a batch.
– 13 –
4.18 Standard deviation of the sample
X)z
s=
(x – n –1 i
i=
This is an estimation of the dispersion of the characteristic x in a batch.
4.19 Acceptance trapezium
A graph, with control limits, on which are plotted two corresponding statistical values (i.e. sample mean x
or average range w), for each sample.
and either standard deviation s
4.20 Acceptable quality level (AQL)
For a given characteristic, the maximum percentage of defective meters in a batch that, for the purpose of
sampling inspection, can be considered satisfactory (E.O.Q.C.).
5. Acceptance conditions for batches
A batch is deemed to comply with the requirements . of this report and shall be accepted if for each inspected
characteristic the proportion of defective meters does not exceed the following specified values:
– no meter shall be accepted with a false constant or faulty insulation (for sampling inspection, see Sub-clauses
9.2.1.1 and 9.2.1.4).
Under test conditions in Clause 7:
not more than 1 % of the meters shall complete one revolution of the rotor with a current of
–
0.001Ib;
– not more than 1% of the meters shall fail to complete one revolution of the rotor with a current of
0.006 Ib;
– not more than 1% of the meters shall have errors exceeding the prescribed limits for each test point (Nos. 4
to 9 in Table II).
In the event of sampling inspection, the above conditions shall be considered satisfied* when for each
characteristic of the meters in the batch:
– for inspection by attributes the number of defective meters in the sample is smaller than or equal to the
acceptance number;
– for inspection by variables the graphically presented test result is within the acceptance trapezium or the
calculated test result does not exceed the specified limits.
6. Place of inspection
The inspection shall be carried out by mutual agreement:
– on the manufacturer's premises, but on test benches other than those on which the adjustments were made;
– or on the purchaser's test benches;
– or on other agreed test benches.
7. Test conditions
7.1 Re
...
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