EN 60851-4:1996

SLOVENSKI STANDARD
01-september-2001
Winding wires - Test methods - Part 4: Chemical properties
Winding wires - Test methods -- Part 4: Chemical properties
Wickeldrähte - Prüfverfahren -- Teil 4: Chemische Eigenschaften
Fils de bobinage - Méthodes d'essai -- Partie 4: Propriétés chimiques
Ta slovenski standard je istoveten z: EN 60851-4:1996
ICS:
29.060.10 Žice Wires
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

NORME
CEI
INTERNATIONALE
IEC
60851-4
INTERNATIONAL
Edition 2.1
STANDARD
1997-11
Edition 2:1996 consolidée par l'amendement 1:1997
Edition 2:1996 consolidated with amendment 1:1997
Fils de bobinage – Méthodes d'essai –
Partie 4:
Propriétés chimiques
Winding wires – Test methods –
Part 4:
Chemical properties
 IEC 1997 Droits de reproduction réservés  Copyright - all rights reserved
Aucune partie de cette publication ne peut être reproduite ni No part of this publication may be reproduced or utilized in
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International Electrotechnical Commission
Pour prix, voir catalogue en vigueur
For price, see current catalogue

60851-4 © IEC:1996 + A.1:1997 – 3 –
CONTENTS
Page
FOREWORD . 5
INTRODUCTION . 7
Clause
1 Scope.9
2 Normative references. 9
3 Test 12: Resistance to solvents (applicable to enamelled round wire with a nominal
conductor diameter over 0,250 mm and to enamelled rectangular wire) . 9
4 Test 16: Resistance to refrigerants (applicable to enamelled round wire) . 11
5 Test 17: Solderability (applicable to enamelled round wire and bunched wire) . 15
6 Test 20: Resistance to hydrolysis and to transformer oil
(applicable to enamelled wire) . 17
Figures. 25

60851-4 © IEC:1996 + A.1:1997 – 5 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
__________
WINDING WIRES – TEST METHODS –
Part 4: Chemical properties
FOREWORD
1) The IEC (International Electrotechnical Commission) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of the IEC is to promote
international cooperation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, the IEC publishes International Standards. Their preparation is
entrusted to technical committees; any IEC National Committee interested in the subject dealt with may
participate in this preparatory work. International, governmental and non-governmental organizations liaising
with the IEC also participate in this preparation. The IEC collaborates closely with the International
Organization for Standardization (ISO) in accordance with conditions determined by agreement between the
two organizations.
2) The formal decisions or agreements of the IEC on technical matters express, as nearly as possible an
international consensus of opinion on the relevant subjects since each technical committee has representation
from all interested National Committees.
3) The documents produced have the form of recommendations for international use and are published in the
form of standards, technical reports or guides and they are accepted by the National Committees in that
sense.
4) In order to promote international unification, IEC National Committees undertake to apply IEC International
Standards transparently to the maximum extent possible in their national and regional standards. Any
divergence between the IEC Standard and the corresponding national or regional standard shall be clearly
indicated in the latter.
5) The IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with one of its standards.
6) Attention is drawn to the possibility that some of the elements of this International Standard may be the subject
of patent rights. The IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 60851-4 has been prepared by IEC technical committee 55:
Winding wires.
This second edition cancels and replaces the first edition published in 1985 and its amend-
ment 1 (1992), and constitutes a technical revision.
This consolidated version of IEC 60851-4 is based on the second edition of IEC 60851-4
(1996) [documents 55/473A/FDIS and 55/514/RVD] and its amendment 1 (1997) [documents
55/597/FDIS and 55/614/RVD].
It bears the edition number 2.1.
A vertical line in the margin shows where the base publication has been modified by
amendment 1.
60851-4 © IEC:1996 + A.1:1997 – 7 –
INTRODUCTION
This part of IEC 60851 forms an element of a series of standards which deals with insulated
wires used for windings in electrical equipment. The series has three groups describing:
a) methods of test (IEC 60851);
b) specifications (IEC 60317);
c) packaging (IEC 60264).
60851-4 © IEC:1996 + A.1:1997 – 9 –
WINDING WIRES – TEST METHODS –
Part 4: Chemical properties
1 Scope
This part of IEC 60851 specifies the following tests:
– Test 12: Resistance to solvents;
– Test 16: Resistance to refrigerants;
– Test 17: Solderability;
– Test 20: Resistance to transformer oil.
For definitions, general notes on methods of test and the complete series of methods of test for
winding wires see IEC 60851-1.
2 Normative references
The following normative documents contain provisions which, through reference in this text,
constitute provisions of this part of IEC 60851. At the time of publication, the editions indicated
were valid. All normative documents are subject to revision, and parties to agreements based
on this part of IEC 60851 are encouraged to investigate the possibility of applying the most
recent editions of the normative documents indicated below. Members of the IEC and ISO
maintain registers of currently valid International Standards.
IEC 60296: 1982, Specification for unused mineral insulating oils for transformers and
switchgear
IEC 60554-1: 1977, Specification for cellulosic papers for electrical purposes – Part 1:
Definitions and general requirements
IEC 60851-1: 1996, Winding wires – Test methods – Part 1: General
IEC 60851-3: 1996, Winding wires – Test methods – Part 3: Mechanical properties
IEC 60851-5: 1996, Winding wires – Test methods – Part 5: Electrical properties
3 Test 12: Resistance to solvents (applicable to enamelled round wire with
a nominal conductor diameter over 0,250 mm and to enamelled rectangular wire)
The effect of solvent on enamel is not practicable for wires up to and including 0,250 mm. The
test should only be applicable to wires over 0,250 mm.
Resistance to solvents is expressed by the pencil hardness of the wire after solvent treatment.
3.1 Equipment
The following solvents shall be used:
– standard solvent as specified below, or
– solvent as agreed between purchaser and supplier.

60851-4 © IEC:1996 + A.1:1997 – 11 –
The standard solvent shall be a mixture of:
– 60 % by volume white spirit with maximum aromatic content of 18 %;
– 30 % by volume xylene;
– 10 % by volume butanol.
The pencil to be used shall be a lead pencil of a hardness as specified in the relevant standard.
Before each test, the point of the pencil shall be sharpened with a smooth-cut file to form an
angle of 60° symmetrical about the axis of the lead according to figure 1.
3.2 Procedure
A straight piece of wire, approximately 150 mm in length, shall be preconditioned for 10 min at
(130 ± 3) °C in an oven with forced air circulation. A substantial length of the wire shall then be
immersed in standard solvent contained in a glass cylinder, and shall be maintained therein at
a temperature of (60 ± 3) °C for a period of 30 min. The wire shall then be removed from the
solvent. The hardness of the wire surface shall then be determined, in the following manner,
within a period of 30 s after removal from the solvent.
The specimen to be tested shall be laid on a smooth hard surface according to figure 1. In the
case of rectangular wires, the test shall be carried out on the flat side of the wire. The pencil
shall be placed on the surface of the wire at an angle of approximately 60° and the sharpened
edge shall be pressed slowly along the surface of the wire with a force of approximately 5 N.
Three tests shall be made. It shall be reported, if the coating is removed with exposure of the
bare conductor.
NOTE 1 – This method can also be used for testing resistance to other fluids, for example oil.
NOTE 2 – Where it is desired to determine the hardness of the insulation, the hardness of the lead pencil which just
fails to remove the coating from the surface of the conductor shall be taken as the hardness of the wire surface,
expressed by the pencil hardness. The pencil hardness series is as follows:
6B 5B 4B 3B 2B B HB H 2H 3H 4H 5H 6H 7H 8H 9H
____________________________________________________________________________________________
45 6789 10 11 12 13 14 15 16 17 18 19
4 Test 16: Resistance to refrigerants (applicable to enamelled round wire)
Resistance to refrigerant 22 is expressed by the quantity of matter extracted from the coating
of the wire and by the breakdown voltage after exposure to a refrigerant.
NOTE 1 – Refrigerants other than monochlorodifluoromethane (refrigerant R 22) may be used. In this case, the
critical data of such fluid should be observed and the layout of the pressure vessel should comply with the test
altered conditions.
NOTE 2 – Refrigerants like monochlorodifluoromethane and rinsing fluids like trichlorotrifluorethane (refrigerant
R 113) are ozone depleting chemicals (ODC). Therefore, it will be necessary to revise this method of test as soon
as substitute materials are identified.
4.1 Extraction
4.1.1 Principle
A siphon cup containing the wire sample is placed in the pressure vessel. The extractable
matter is determined after exposure of the wire sample to the refrigerant under pressure and at
elevated temperature.
60851-4 © IEC:1996 + A.1:1997 – 13 –
4.1.2 Equipment
The following equipment shall be used:
– siphon cup according to figure 2, of 450 ml volume up to the siphoning level;
– pressure vessel of 2 000 ml volume with an internal diameter of approximately 100 mm and
a pressure capacity of 200 bar (20 MPa), preferably of unwelded construction and provided
with a controlled heating system;
– top closure of the vessel containing a condenser coil according to figure 3;
– oven with forced air circulation.
4.1.3 Specimen
Eight wire samples each containing (0,6 ± 0,1) g of insulation shall be wound into coils of 70 turns.
The specimens shall be degreased and conditioned in an oven with forced air circulation at
(150 ± 3) °C for 15 min. After 30 min cooling, the eight specimens shall be weighed together to
the nearest 0,0001 g, resulting in the total initial mass M .
4.1.4 Procedure
The eight specimens shall be placed in the siphon cup, which is suspended (25 ± 5) mm below
the condenser coil on the pressure vessel cover. The pressure vessel shall be assembled and
charged with (700 ± 25) g of refrigerant 22. The condenser water supply and drain line shall be
connected and the pressure vessel shall be heated by means of a controlled heating system
with the temperature set between 70 °C and 80 °C. The water flowing through the condenser
shall be adjusted to maintain a reflux rate of 20 to 25 discharges per hour from the siphon cup.
The extraction period shall be 6 h.
The vapour pressure of refrigerant 22 corresponding to the temperature range as specified
above is 30 bar to 37 bar (3 MPa to 3,7 MPa). The critical pressure of refrigerant 22 is 50 bar
(5 MPa). The pressure in the vessel shall not exceed 40 bar (4 MPa). Therefore, prior to use
the over-pressure control valve shall be checked to ensure its proper functioning.
NOTE – It is recommended that the heating system is automatically deactivated, if the pressure exceeds 40 bar
(4 MPa) or if the water flow through the condenser coil is interrupted.
At the end of the extraction period, the pressure vessel shall be cooled by means of solid
carbon dioxide to liquify the refrigerant, the pressure shall be released and the pressure vessel
opened. The specimens and siphon cup shall be rinsed with distilled trichlorotrifluor-ethane
(oil-free R 113) (see note 2 of this clause). The rinse shall be poured into the pressure vessel.
The refrigerant shall then be evaporated to approximately 5 mm of the bottom of the pressure
vessel. The walls of the pressure vessel shall be washed with two successive rinses each of
100 ml methylene chloride and the solvents shall then be evaporated under a hood or in a well-
ventilated area to approximately 5 mm from the bottom of the pressure vessel.
The liquid sample shall be transferred to a pre-dried tared aluminium weighing dish with a 15 ml
methylene chloride rinse and t
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