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1 H) v U$ J2 [5 ?2 m4 R0 I. IQuestion:) I8 x v" q" I- {+ n5 b5 O
How is non-separable thin sheet insulation in wound components tested?; I9 n4 V# }7 j: R/ {, t
Rationale:
" r8 v( h7 J9 I3 L% H" rThere are non-separable thin sheet foils on the market and used in wound components,
; }+ F0 I7 U! |5 l1 O1 g0 p& Bwhich cannot be tested according to the requirements and test-method in the existing; N4 z! K9 D+ [" \6 N( @( I
standard. A proposal was made to TC74-WG6 how this matter can be handled. The
0 U3 b) t/ a7 Yproposal is attached.3 l9 t; j0 ^7 p6 z+ {, O$ M. s
Decision:
* C( ]: a8 r2 a3 h) RUse of non-separable thin sheet insulation in wound components9 Y S/ h3 r1 Z. V5 }
The following proposal shall be used until the new edition is published.
, f( Q" h+ k) h5 x' v1. Introduction p2 l5 R- w6 |- O
This document presents two alternative versions of the test procedure given in IEC8 g2 i3 x% a1 ]
61558-1 for checking the mechanical durability of thin sheet materials.
S' }9 H* @& u8 k9 ]Test method X adapts the published procedure to the conventions and practices used in
8 r: r8 ~3 M$ V9 M! P: M3 rIEC 60950. In Method X, the metal foil is secured to the sample prior to the test.2 A/ S1 a/ l0 Y0 B6 x2 M/ t8 L9 A
Test method Y is the slightly different procedure observed on a video presentation,
) Z% q, y! [3 L4 Hwhereby the metal foil is only added to the test assembly after the sample has been
3 w; R% E- a& e" a3 q4 nstressed by rotating it in the test fixture.
8 X- }7 p% g6 c$ b2 S! s. v! R/ OTest method Y appears to be the more practical method, and is evidently how the test is0 y5 n s n/ z
carried out in at least one test laboratory. The two methods should give the same results.8 U' v1 v9 U$ h3 R) u" e6 u. n! G7 j# H
2. Proposal
% D$ Q3 L3 F: z3 Y0 a$ l3 RChange the title of 2.10.5.2 to the following:; ]' Z% C I$ H+ ?9 w* p K% s2 v
2.10.5.2 Separable thin-sheet material2 r: O- {( c9 f0 F+ r. t1 a
Modify the first paragraph of 2.10.5.2 as follows:& }0 I* c( Z* V1 e9 |( |" s
Insulation in separable thin sheet materials, and in two layers of non-separable thin sheet
! O( J* H# @1 I# ]. pmaterials, is permitted, ….. L# V& h, H. V9 t
Add a new sub-clause 2.10.5.X or 2.10.5.Y.* G8 W! x5 A; l% Q0 u6 ?: T/ N% D' |
Test Method X6 Q7 H+ k1 j4 G; g% Y0 n: r. X
2.10.5.X Non-separable thin sheet material
4 T2 P9 T) f4 @) G6 [Insulation in three or more layers of non-separable thin-sheet materials is permitted for use within
1 K7 L; `( c4 m2 w& \, N: O, athe equipment ENCLOSURE, and shall not be subject to handling or abrasion during servicing. It
) D/ e G& U8 m4 \4 Q' dshall have adequate mechanical strength.
: ?6 Z* R( `! Q3 L% K ^& mNOTE - The purpose of the tests in 2.10.5.X is to reveal defects that are hidden in inner layers of insulation,
. i3 z4 n+ }" m, c" o) Vso there is no test for insulation in two layers. For insulation in two layers of non-separable thin-sheet) I6 W5 P6 C/ I: }1 I; d @
materials, see 2.10.5.2; c6 _# M3 H Q. G+ [
There is no requirement regarding distances through insulation, nor for all layers of insulation to be- i( d3 t% ~! X3 m# q# k
of the same material.; A' E) t) h2 Z& U) G
Compliance is checked by inspection and by the following test:
6 a6 I" w: X9 z E9 |5 |" wThree test samples of thin sheet material are used, each approximately 70 mm wide.0 H7 g) z4 ~: ]& @- h @, F0 \
One sample is fixed to the mandrel of the test fixture as shown in figure 5X.1 G3 ^: H; ]" C( Z5 o
A sheet of aluminium or copper foil, 0,035 mm ± 0,005 mm thick, approximately 30 mm wide and at3 \1 o* }& G( k$ P9 u
least 100 mm long, is fixed to the surface of the sample. The foil is positioned so that its edges are
v g4 o8 O! U6 _; [7 z; rapproximately 20 mm from the edges of the sample (see figure 5Xd) and so that when the/ Y) f# z9 D D; E) j8 s" [
mandrel is in its final position, the foil overlaps the free end of the sample by at least 10 mm (see* C7 Z5 D5 Q/ j1 }$ ^% P
figure 5Xc). The foil is tightened by a pull of approximately 1 N, using an appropriate clamping
- ?, t6 \- N* Z& ?' Ddevice.$ }. w4 A- s+ X; e# u, d
A pull of 150 N is applied to the free end of the sample, using an appropriate clamping device. The/ S7 j8 i0 z* g [
mandrel is twice rotated forwards and backwards by 230°, and then forwards to the final position.
8 M( g9 W9 E; i/ l& s+ fWhile the mandrel is in its final position, and within the 60 s following the final positioning, an
& w& z( X. K. ^electric strength test is applied between the mandrel and the metal foil in accordance with 5.2.2,( G" C( `3 ]" V
using a test voltage of 1,5 times the value specified in table 5B.7 F. S. j; |! H' T, [. X
The test is repeated with the other two samples9 H) u4 W& z X7 B" ~
If a sample breaks at the clamping device during rotation, the test is repeated on a fresh sample. If0 |, I' b; ?! j6 Q2 I: V& W' P
one or more samples breaks at any other place, the test has failed.
' t/ y7 S8 f% i& Y: J2 L............................
% g, F4 `$ x! G" @7 x, `" F% aAdd new Figure 5X (adapted from Figure 6 of IEC 61558-1)
3 t/ u3 ?, x& `8 eFigure 5Xa is as figure 6a of IEC 61558-1, modified as follows:
* n5 x, ^7 @% ~& D+ l% t% \Replace "3 x R = 0,5 ± 0,02" by "R = 0,5 ± 0,02 (typ)"% k) {3 w2 F/ y6 h. b7 F/ ?
Replace "Material: steel nickel plated or brass" by "Material: metal"
! s# T: P1 |. X$ h) jFigure 5Xd is the same as figure 6c of IEC 61558-13 [) x( A, O% ~$ q
Test Method Y
E$ {% ^8 ^6 k& ]8 s' B0 w2.10.5.Y Non-separable thin sheet material
- S9 }8 u$ m1 Z; @Insulation in three or more layers of non-separable thin-sheet materials is permitted for use within
! t1 x3 I$ A) E' ^/ Bthe equipment ENCLOSURE, and shall not be subject to handling or abrasion during servicing. It
9 r( ~% x$ c- G; ]) O5 V( eshall have adequate mechanical strength.; d3 A' N* w- o; _
NOTE - The purpose of the tests in 2.10.5.y is to reveal defects that are hidden in inner layers of insulation,4 O" X0 J$ o j4 ~
so there is no test for insulation in two layers. For insulation in two layers of non-separable thin-sheet
% @* a* j8 |* x- D2 t: Vmaterials, see 2.10.5.2$ W+ R- k) _& i( i) e% |
There is no requirement regarding distances through insulation, nor for all layers of insulation to be
" @" k f' A& q7 ^' `+ uof the same material.* N% @$ w- J) ~, O2 |
Compliance is checked by inspection and by the following test:1 y9 m' U! j2 M! q( D
Three test samples of thin sheet material are used, each approximately 70 mm wide.+ `5 H3 ^2 |4 h
One sample is fixed to the mandrel of the test fixture as shown in figure 5Y. V/ x% Q" X+ }) ~3 ~8 |& u, Z& C4 _, H
A pull of 150 N is applied to the free end of the sample, using an appropriate clamping device. The
# n) P/ o4 X. x) U+ }4 smandrel is twice rotated forwards and backwards by 230°, and then forwards to the final position.0 T, \7 d6 a( a
A sheet of aluminium or copper foil, 0,035 mm ± 0,005 mm thick, approximately 30 mm wide and at
( k( O- ^' S1 y; b) c$ u* \, c2 _least 200 mm long, is placed across is the surface of the sample, hanging down on each side of, s( ~9 E! G! B# ]+ w+ `
the mandrel. The foil is tightened by a pull of approximately 1 N at each end, using appropriate8 V( i/ Y+ |* B# ^- A
clamping devices.. The foil is positioned so that its edges are approximately 20 mm from the edges& L( |2 A4 y# H
of the sample (see figure 5Yd).
, n" c4 q7 F) O- b5 H7 n2 e1 I7 P! \While the mandrel is in its final position, and within the 60 s following the final positioning, an
9 V& ?) e) [7 v% X4 C6 e8 Yelectric strength test is applied between the mandrel and the metal foil in accordance with 5.2.2,! w9 p2 H b: C. [* v
using a test voltage of 1,5 times the value specified in table 5B.7 f; T- o; y4 E' v0 o+ s
The test is repeated with the other two samples
5 ?: g) s( [* N0 l! T3 C8 yIf a sample breaks at the clamping device during rotation, the test is repeated on a fresh sample. If
, {% Z4 P1 w) Y9 z# V: p fone or more samples breaks at any other place, the test has failed.4 r3 E3 t2 A9 A. B* @/ A4 N, Y
...............................$ K) o8 B7 V/ m* T# ^' ?+ }1 `2 p
Add new Figure 5Y (adapted from Figure 6 of IEC 61558-1)
* O8 n$ `* l/ i( U1 h$ G6 MFigure 5Ya is as figure 6a of IEC 61558-1, modified as follows:
5 X$ g2 H3 j3 A( s- c8 J4 L% t3 xReplace "3xR = 0,5 ± 0,02" by "R = 0,5 ± 0,02 (typ)"
3 `* ~9 X. v- [% |$ c# u4 F# fReplace "Material : steel nickel plated or brass" by "Material: metal"
! o4 T/ P! Q" g6 n: ^! z; R0 i4 `/ OFigure 5Yd is the same as figure 6c of IEC 61558-1, h$ M( T4 @/ [" H1 _' q. l
; ^( D H0 U/ l) W9 @* j2 i+ b
9 S6 \ f2 A. a& C' b1 l: F* L8 ~9 q% Y. }& c& u
* g9 l" d0 w, g" [ |
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