IEC TR 60079-15:1987
(Main)Electrical apparatus for explosive gas atmospheres. Part 15: Electrical apparatus with type of protection 'n'
Electrical apparatus for explosive gas atmospheres. Part 15: Electrical apparatus with type of protection 'n'
Specifies requirements for the construction, assessment and testing of electrical apparatus with type of protection 'n' which, when operating normally within its rated duty, is unlikely to be capable of igniting a surrounding explosive gas atmosphere. This publication has the status of a report.
Matériel électrique pour atmosphères explosives gazeuses. Quinzième partie: Matériel électrique avec mode de protection 'n'
Spécifie les règles de construction, d'évaluation et d'épreuves de matériel électrique avec mode de protection «n» qui, lorsqu'il fonctionne normalement à son service assigné, n'est pas susceptible d'enflammer une atmosphère explosive gazeuse environnante. Cette publication a le statut d'un rapport.
Števci jalove energije
General Information
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Standards Content (Sample)
SLOVENSKI STANDARD
01-avgust-1995
Števci jalove energije
Var-hour (reactive energy) meters
Compteurs d'énergie réactive (varheuremètres)
Ta slovenski standard je istoveten z: IEC 60145
ICS:
17.220.20 0HUMHQMHHOHNWULþQLKLQ Measurement of electrical
PDJQHWQLKYHOLþLQ and magnetic quantities
91.140.50 Sistemi za oskrbo z elektriko Electricity supply systems
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
NORME CEI
INTERNATIONALE IEC
INTERNATIONAL
Première édition
STANDARD
First edition
Compteurs d'énergie réactive (varheuremètres)
Var-hour (reactive energy) meters
de reproduction réservés — Copyright — all rights reserved
© CEI 1963 Droits
No pa of this publication may be reproduced or utilized in
Aucune partie de cette publication ne peut être reproduite ni rt
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CONTENTS
Page
FOREWORD
PREFACE 5
Clause
1. Scope 7
2. Units 7
Definitions 7
3.
13 4. Classification
5. Mechanical requirements
6. Electrical requirements
Markings of meters — Nameplates 7.
8. Accuracy
Connection diagrams and terminal markings 9.
Graphical symbols for var-hour meters APPENDIX —
— 5 —
INTERNATIONAL ELECTROTECHNICAL COMMISSION
VAR-HOUR (REACTIVE ENERGY) METERS
FOREWORD
1) The formal decisions or agreements of the I.E.C. 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 inter-
national 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 this international unification, the I.E.C. expresses the wish that all National Committees having
as yet no national rules, when preparing such rules, should use the I.E.C. recommendations as the fundamental basis
for these rules in so far as national conditions will permit.
4) The desirability is recognized of extending international agreement on these matters through an endeavour to harmonize
national standardization rules with these recommendations in so far as national conditions will permit. The National
Committees pledge their influence toward that end.
PREFACE
These Recommendations were prepared by Sub-Committee 13A, Integrating meters, of Technical
Committee No. 13, Measuring instruments.
Drafts were discussed at meetings held in Stockholm in 1958 and in Paris in 1960. The final draft
was submitted to the National Committees for approval under the Six Months' Rule in April 1961.
The following countries voted explicitly in favour of publication :
Austria
Netherlands
Belgium
Norway
Czechoslovakia
Romania
Denmark Sweden
Finland Switzerland
France
Turkey
Germany
Union of Soviet Socialist Republics
Hungary
United Kingdom
Italy Yugoslavia
Japan
VAR-HOUR (REACTIVE ENERGY) METERS
1. SCOPE
The present recommendations apply only to newly manufactured induction type var-hour meters
for the measurement of reactive energy of frequency between 40 and 60 Hz (c/s), of an accuracy
class of 3.0 for ordinary usage and to their type tests.
They do not apply to special types of var-hour meters except multi-rate meters.
They do not apply to instrument transformers, even when used in conjunction with the meters
covered by these recommendations.
2. UNITS
The units employed in these recommendations are those adopted by the International Electro-
technical Commission.
DEFINITIONS
3.
Some of the following terms have been taken from those given in the International Electrotechnical
20 (Publication 50 (20) (1958). In such cases the appropriate I.E.V. reference is
Vocabulary, Group
given. Some other terms or their definitions have been added especially for these recommendations.
(reactive energy meter)
3.1 Var-hour meter
An integrating instrument which measures reactive energy * in var-hours or in suitable multiples
thereof.
3.2 Induction meter
A meter in which fixed coils carrying current act upon a conducting moving element, generally
a disk, in which flow currents induced by the coils (I.E.V. 20-25-065).
is not available in the I.E.V., and general definitions for reactive power and energy do not
* The term reactive energy
exist for cases where the alternating quantities are not sinusoidal.
For these reasons the present recommendations are based on the following practical definitions, which are strictly
correct only for sinusoidal voltages, but which are for practical purposes true where the voltages and currents are nearly
sinusoidal.
Reactive energy in a single-phase circuit
Quantity measured by a perfect watt-hour meter which carries the current of a single-phase circuit and a voltage equal
in magnitude to the voltage across the single-phase circuit but in quadrature therewith. The reactive energy of an inductive
circuit is positive.
Reactive energy in a polyphase circuit
The algebraic sum of the reactive energies of the phases.
Because these practical definitions of reactive energy assume sinusoidal quantities, the inductive or capacitive state
of a circuit in these recommendations is given by the factor " sin ".
y
— 9 —
3.3 Multi-rate meter
A meter provided with a number of registers each becoming operative at times corresponding
to differing rates of charge (I.E.V. 20-25-110).
3.4 Meter rotor
The moving part of a meter upon which the fixed windings react.
Driving element of an induction meter
3.5
One of the working parts of the meter which produces a torque by its action on the moving element.
It generally comprises an electro-magnet with its control devices (I.E.V. 20-35-185).
Meter braking element
3.6
That part of a meter which is intended to produce a braking torque by its action on the moving
element. It comprises one or more magnets and their setting device (I.E.V. 20-35-190).
Register of a meter (counting mechanism)
3.7
That part of a meter which registers the energy, or more generally the value of the quantity measured
by the meter (I.E.V. 20-35-180).
3.8 Meter base
The back of the meter by which it is fixed and to which are attached the frame, the terminal block
and the cover (I.E.V. 20-35-160).
3.9 Meter cover
The enclosure on the front of the meter, made sometimes of transparent material, but generally
including transparent parts through which the movement of the disk can be seen, and the counting
mechanism read (I.E.V. 20-35-170).
3.10 Meter case
This comprises the base and the cover (I.E.V. 20-35-175).
Meter frame
3,11
That part to which are affixed the driving element, the counting mechanism, usually the braking
element, and sometimes the adjusting devices (I.E.V. 20-35-165).
3.12 Terminal block
A support made of insulating material on which all terminals of an instrument, or part of them,
are grouped together (I.E.V. 20-35-135).
Terminal cover
3.13
Auxiliary cover which covers the meter terminals and the ends of the wires or the cables from the
apparatus connected to these terminals (I.E.V. 20-35-195 modified).
3.14 Current circuit
That part of a meter through which flows the current in the circuit which it measures, or a pro-
portional current supplied by a current transformer (I.E.V. 20-35-205 modified).
— 11 —
3.15 Voltage circuit
That part of a meter supplied by the voltage of the circuit it is to measure or by a proportional
voltage supplied by a transformer or voltage divider (I.E.V. 20-35-210 modified).
3.16 Auxiliary circuit(s)
Circuit(s) within the meter case and connected to an auxiliary device, for example, an hour meter,
a clock, a trip coil, a relay.
Basic current
3.17
The value of the current which serves as a basis for these recommendations.
Rated maximum current
3.18
The value of current up to which the meter purports to meet the highest accuracy requirements
of these recommendations.
3.19 Reference voltage
The value of voltage which forms the basis of these recommendations, if the meter is marked for
one voltage only.
If the meter is marked for a range of voltages of which the ratio between the upper and lower limits
does not exceed 1.3 *, the reference voltage is the arithmetic mean of the extreme values of the range,
for all tests except those prescribed in Sub-Clauses 8.2.1 and 8.2.5.
If the meter is marked for two voltages of which the ratio between the higher one and lower one
exceeds 1.3, these two voltages are to be considered as reference voltages and all the tests are to be made
for both.
-hour meters for 3-phase circuits, the reference voltage will be the voltage applied to the
In var
voltage circuit(s), which may include external devices.
Reference frequency
3.20
The frequency which forms the basis of these recommendations.
3.21 Reference speed
The number of revolutions per minute of the rotor when the meter carries reference voltage, and
basic current, sin y = 1.
3.22 Reference torque
The torque of the rotor when at rest, when the meter carries reference voltage and basic current,
sin = 1.
*U
upper
1.3
U
lower
— 13 —
3.23 Constant of a var-hour meter
Coefficient giving the relation between the reactive energy nominally measured by a meter and the
corresponding angular movement of the rotor.
It is usually expressed as var-hours per revolution (varh/rev) or in revolutions per kilovar-hour
(rev/kvarh).
Reference temperature
3.24
The ambient temperature for which the meter is intended.
3.25 Type tests
Qualifying tests which are made on a meter, or on a small number of meters of the same type.
3.26
Routine tests
Tests carried out on every meter in a consignment.
3.27
Sampling tests
Tests carried out on a sample of a consignment.
3.28 Errors
a) Absolute error
The indicated value of reactive energy minus its true value . expressed algebraically (I.E.V.
20-40-085 modified).
b) Relative error
The ratio of the absolute error to the true value of the reactive energy (I.E.V. 20-40-090 modified).
c) Percentage error
Relative error x 100.
3.29 Distortion factor
The ratio between the r.m.s. value of the harmonic content obtained by subtracting the funda-
mental wave from a non-sinusoidal periodic quantity and the r.m.s. value of the non-sinusoidal quantity.
It is usually expressed as a percentage.
3.30 Mean temperature coefficient
The ratio between the relative variation of a quantity and the change of temperature which
produces it.
4. CLASSIFICATION
4.1 Var-hour meters may be classified according to :
— Class of accuracy, each class being denoted by a number corresponding to the percentage accuracy
limit at basic current and sin = 1 under the conditions of Sub-Clause 8.2.1.
p
In this edition of the recommendations the meters concerned are classified as 3.0.
— 15 —
— Degree of phase displacement, each class of single driving element * of a var-hour meter which is
characterized by the nominal phase displacement between the voltage and current magnetic
fluxes in the principal air gaps when the voltage and current applied to this single driving
element are in phase.
Var-hour meters which are the subject of these recommendations usually fall into one of three
classes : 0, 90 and 60.
MECHANICAL REQUIREMENTS
5.
5.1 General
All insulating materials used in the construction of meters shall be substantially non-hygroscopic.
All parts which are subject to corrosion under normal working conditions shall be effectively
protected against corrosion due to atmospheric causes. Any protective coating shall not be liable to
damage by ordinary handling nor injuriously affected by exposure to air, under ordinary conditions of
service.
5.2 Case
The meter shall have a reasonably dust-proof case, which can be sealed such that the mechanism
of the meter is only accessible after breaking the seals.
Metal cases of meters for use on a voltage exceeding 250 V to earth shall be provided with means
for the effective connection of an adequate earthing conductor.
5.3
Windows
If the meter case is not transparent, one or more windows shall be provided for reading the register
and the observation of the rotor. These windows shall be covered by plates of transparent material,
which cannot be removed without breaking the seals.
5.4 Terminals — Terminal block
The terminals shall be grouped in a terminal block of adequate mechanical strength. They shall
permit the connection of both solid and stranded conductors. It shall be possible easily to disconnect
the voltage terminals from the current terminals.
The manner of fixing the conductors to the terminals shall ensure adequate and durable contact
such that there is no risk of loosening or undue heating. The holes in the insulating material which form
a prolongation of the terminal holes shall be of sufficient size to accommodate the insulation of the
conductors.
5.5 Terminal cover
The terminals of a meter shall have a separate cover which can be sealed independently of the meter
cover. The terminal cover shall enclose the actual terminals, their fixing screws, and if required a suitable
length of the external conductors, and their insulation.
* Driving element here includes any necessary accessory resistors, inductors and shunts.
— 17 —
When the meter is fixed, no access to the terminals shall be possible without breaking the seals
of the terminal cover.
5.6 Register (counting mechanism)
The register may be of the pointer or of the drum type.
The principal terms in which the register records shall be the kilovar-hour (kvarh) or the megavar-
hour (Mvarh).
In drum type registers, the terms in which the register records shall be
...
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