Test methods for the determination of bond strength of impregnating agents to an enamelled wire substrate
Describes three test methods to determine the bond strength of impregnating agents such as solvent-based varnishes and solventless resins. The three test methods most commonly used are: Twisted coil test, Helical coil test, Wire bundle test.
Prüfverfahren zur Bestimmung der Verbackungsfestigkeit von Imprägniermitteln auf einem Lackdraht-Substrat
Méthodes d'essai pour la détermination du pouvoir agglomérant des agents d'imprégnation sur fil émaillé
Décrit trois méthodes d'essai pour déterminer le pouvoir agglomérant d'agents d'imprégnation tels que des vernis avec solvants et des résines sans solvants. Ces trois méthodes d'essai couvrent les méthodes standards habituellement utilisées: Méthode de la bobine torsadée, Méthode de la bobine hélicoïdale, Méthode du faisceau de fils.
Preskusne metode za ugotavljanje vezalne moči impregnacijskih snovi na emajlirano žično podlago (substrat) (IEC 61033:1991 (EQV) + A1:2006)
Standards Content (sample)
SIST EN 61033:2007
Test methods for the determination of bond strength of impregnating agents to an
enamelled wire substrate (IEC 61033:1991 (EQV) + A1:2006)
Prüfverfahren zur Bestimmung der Verbackungsfestigkeit von Imprägniermitteln auf
einem Lackdraht-Substrat (IEC 61033:1991 (EQV) + A1:2006)
Méthodes d'essai pour la détermination du pouvoir agglomérant des agents
d'imprégnation sur fil émaillé (IEC 61033:1991 (EQV) + A1:2006)
Ta slovenski standard je istoveten z: EN 61033:2006
17.220.99 Drugi standardi v zvezi z Other standards related to
elektriko in magnetizmom electricity and magnetism
29.035.01 Izolacijski materiali na Insulating materials in
SIST EN 61033:2007 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.---------------------- Page: 1 ----------------------
ICS 17.220.99; 29.035.01
Test methods for the determination of bond strength
of impregnating agents to an enamelled wire substrate
(IEC 61033:1991 + A1:2006)
Méthodes d'essai pour la détermination Prüfverfahren zur Bestimmung
du pouvoir agglomérant des agents der Verbackungsfestigkeit
d'imprégnation sur fil émaillé von Imprägniermitteln auf einem
(CEI 61033:1991 + A1:2006) Lackdraht-Substrat
(IEC 61033:1991 + A1:2006)
This European Standard was approved by CENELEC on 2006-11-01. CENELEC members are bound to comply
with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standardthe status of a national standard without any alteration.
Up-to-date lists and bibliographical references concerning such national standards may be obtained onapplication to the Central Secretariat or to any CENELEC member.
This European Standard exists in three official versions (English, French, German). A version in any other
language made by translation under the responsibility of a CENELEC member into its own language and notifiedto the Central Secretariat has the same status as the official versions.
CENELEC members are the national electrotechnical committees of Austria, Belgium, Cyprus, the Czech
Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain,Sweden, Switzerland and the United Kingdom.
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
Central Secretariat: rue de Stassart 35, B - 1050 Brussels
© 2006 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.Ref. No. EN 61033:2006 E
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EN 61033:2006 - 2 -
The text of the International Standard IEC 61033:1991 + A1:2006, prepared by IEC TC 15, Standards on
specifications for electrical insulating materials, was submitted to the Unique Acceptance Procedure andwas approved by CENELEC as EN 61033 on 2006-11-01 without any modification.
The following dates were fixed:
– latest date by which the EN has to be implemented
at national level by publication of an identical
national standard or by endorsement (dop) 2007-11-01
– latest date by which the national standards conflicting
with the EN have to be withdrawn (dow) 2009-11-01
Annex ZA has been added by CENELEC.
The text of the International Standard IEC 61033:1991 + A1:2006 was approved by CENELEC as aEuropean Standard without any modification.
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- 3 - EN 61033:2006
Normative references to international publications
with their corresponding European publications
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenceddocument (including any amendments) applies.
NOTE When an international publication has been modified by common modifications, indicated by (mod), the relevant EN/HDapplies.
Publication Year Title EN/HD Year
IEC 60317 Series Specifications for particular types of winding EN 60317 Series
ISO 178 1975 Plastics - Determination of flexural properties - -
of rigid plastics
---------------------- Page: 4 ----------------------
Méthodes d'essai pour la détermination du
pouvoir agglomérant des agents d'imprégnation
sur fil émaillé
Test methods for the determination of bond
strength of impregnating agents to an enamelled
© IEC 1991 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
utilisée sous quelque forme que ce soit et par aucun any form or by any means, electronic or mechanical,
procédé, électronique ou mécanique, y compris la photo- including photocopying and microfilm, without permission in
copie et les microfilms, sans l'accord écrit de l'éditeur. writing from the publisher.International Electrotechnical Commission 3, rue de Varembé Geneva, Switzerland
Telefax: +41 22 919 0300 e-mail: email@example.com IEC web site http: //www.iec.ch
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Pour prix, vigueur
voir catalogue en
• • For price, see current catalogue
---------------------- Page: 5 ----------------------
- 3 -
1033 © I E C
2 Methods of test
2.1 Method A: twisted coil test 7
2.2 Method B: helical coil test 11
2.3 Method C: Wire bundle test 13
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1033 IE C - 5 -
INTERNATIONAL ELECTROTECHNICAL COMMISSION
TEST METHODS FOR THE DETERMINATION OF BOND STRENGTH OF
IMPREGNATING AGENTS TO AN ENAMELLED WIRE SUBSTRATE
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
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 con-
ditions will permit. Any divergence between the IEC recommendation and
the corresponding national rules should, as far as possible, be clearly
indicated in the latter.
This standard has been prepared by Sub-Committee 15C: Specifications, of
IEC Technical Committee No. 15: Insulating materials.
The text of this standard is based on the following documents:
Six Months' Rule
Report on Voting
Full information on the voting for the approval of this standard can be
found in the Voting Report indicated in the above table.
This standard replaces IEC 290, published in 1969, and IEC 699, published
The following IEC publication is quoted in this standard:
Publication No. 317: Specifications for particular types of winding
Other publication quoted:
ISO 178 (1975): Plastics - Determination of flexural properties of
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TEST METHODS FOR THE DETERMINATION OF BOND STRENGTH OF
IMPREGNATING AGENTS TO
AN ENAMELLED WIRE SUBSTRATE
This standard deals with three methods of test to determine the bond
strength of impregnating agents in conjunction with enamelled wire sub-
The methods are as follows:
1) Twisted coil test: method A
2) Helical coil test: method B
3) Wire bundle test: method C
This standard describes three methods of test to determine the bond
strength of impregnating agents such as solvent-based varnishes and
solventless resins to an enamelled wire substrate. Bond strength may be
affected by cure, by test temperature, by thermal ageing, and for any
impregnating agent, by the chosen type of wire enamel.
These three methods of test cover the prevailing standard practice of
testing bond strength. For a certain group of materials, one of these
methods may be assigned to be the referee method subject to a specifi-
cation in the relevant specification sheet.
2 Methods of test
Method A: twisted coil test
In this test, 0,315 mm diameter enamelled winding wire in the form of a
twisted coil is impregnated and cured. The maximum force to break this
specimen is a measure of the bond strength.
Prepare a random wound coil from an enamelled winding wire (see note 1)
by means of a suitable winding equipment (see figure la). To prevent
opening of the coil after removal from the winding equipment, each end of
the winding wire, or short piece of enamelled wire may be wrapped around
the coil two or three times in opposite directions. For this purpose the
winding equipment is provided with appropriate notches (see figure lb).
For winding the coil, the following dimensions apply:
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1033 © IEC - 9 -
winding diameter: 57 mm ±
width of the slot: 6 mm 1 mm
number of turns: 100 (see note 2)
nominal wire diameter: 0,315 mm
1 For enamelled winding wire see also IEC 317.
2 Instead of 100 turns, two times 50 turns may be used to provide a
bifilar winding that allows a.c. current heating of the coil if
Remove the coil from the winding equipment and stretch it into an oval
shape. Twist the coil two full turns around its longitudinal axis by means
of a twisting device (see figures 2a and 2b) . The twisted coil formed is
about 7 mm in diameter and 85 mm to 90 mm in length and serves as
substrate for the impregnating agent.
Unless otherwise specified in the purchase contract, treat the twisted coil
once with the impregnating agent. With the twisted coil in the vertical
position, immerse it in the impregnating agent for 5 min ± 1 min (see
note). Remove it slowly and uniformly at a maximum rate of 1 mm/s. Drain
horizontally for 10 min to 15 min and cure horizontally according to the
manufacturer's recommendation or to an agreed schedule. If more than one
treatment is to be given, dip, drain and cure the twisted coil vertically,
reversing the direction for each subsequent treatment.
Prepare five specimens for each test temperature.
NOTE - Some impregnating agents, such as high viscosity or thixotropic
products may require alternative processing methods.
Use equipment according to ISO 178.
Dimensions of the supports of the test equipment shall comply with
With the specimen properly positioned according to figure 3, adjust the
crosshead speed so that the maximum force is reached in about 1 min.
For tests at elevated temperatures (see note), a heating cabinet attached
to the equipment may be used. Before testing, the test specimen shall be
kept in the cabinet at the test temperature for a time just sufficient to
ensure that the test specimen reaches this temperature. Extended heating
of the specimen could affect the property.
NOTE - In case of current heating, the test temperature of the test
specimen should be determined by adequate means, e.g. thermocouple,
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1033 © IEC - 11 -
The bond strength is expressed as the median value of the five measure-
ments in newtons.
Report the following:
reference to test method A of this standard;
- details of the impregnating agent;
details of the substrate (type of enamelled winding wire);
details of specimen preparation (single or bifilar coil, impregnating
- test temperatures;
bond strength and the minimum and maximum measured values for
each test temperature;
if the winding wire or test specimens have been washed in any
manner so that they are no longer in an "as received" condition, such
procedure shall be noted in the report.
Method B: helical coil test
In this test,
1 mm diameter wire in the form of a helical coil is coated with
varnish and cured. The force necessary to break this coil is a measure of
the bond strength.
Prepare a helical coil (see figure 4) from an enamelled winding wire (see
note) by means of a suitable winding equipment. For winding the coil, the
following dimensions apply:
nominal wire diameter:
mandrel diameter: ±
6,3 mm 0,1 mm
length of coil:
75 mm ± 2 mm