3 R) d7 m! E1 V; s0 W! h+ x
Standard: IEC 61558-1/1997 4 q5 |$ h/ q2 H/ F Q. ^Sub clause: 26.2 7 [' a; A7 o: w9 u% LSheet N°: 594/068 ^/ s5 E! d' A% M! o1 M
Page: 1(1) , l3 [; O+ Z C2 e BSubject: Creepage distances* ~3 f) k* l e
Key words: b2 G: p; ]7 U4 d
- Creepage distances+ P, _, p, P) Z# S& w6 i! ^) U
- Reduced value ; N9 W, m9 v5 A* e7 g- Impregnation9 d e2 G3 }8 D x
Meeting:. q8 L$ w: J6 M* U
Decision confirmed; v2 m% A, m! O, r. C% D
at 44th CTL meeting ' @! ?9 p: ?; x$ MQuestion: Clause 26 of the standard lists several requirements regarding creepage7 T3 d: @: Z I' h/ W
distances, clearances and distances through insulation. In particular, paragraph 4 3 g/ Y. Q# H! b) `of subclause 26.2 states: “The reduced values shown in Table 13, C.1 and D.1 % C; Q' w- _: n. L& f1 mcan be used when separation is made by the use of impregnation, potting, or by' l; j+ [6 J! W/ S
the use of adhesive bonding tape covering the windings, provided that the tests7 w# w( T+ a$ Q, t% ?
of 4.1.1.2.1 of IEC 60664-1 are fulfilled”. To check whether the parts are 5 ^6 J: _8 q5 `( M7 {! Z# Gadequately potted, impregnated or cemented together, the tests according to 0 N; J4 `. c4 xprocedure A) or B) are conducted. If a transformer is impregnated or potted on4 r# h; I- d+ A$ E {- V! C
the outside only, and the impregnation material has not penetrated inside it, e.g.7 y4 O3 f/ n4 B/ ~
between primary and secondary winding or between winding and core, can the: G, r4 U4 w3 ^ ~/ R% P& m7 O
reduced values of Table 13, C.1, D.1 be taken into account? : a2 ~& f9 T( p6 Z! G2 sDecision: Yes, According to the IEC 61558-1, it is not required that the impregnation or / ^7 N. z, C/ @5 {5 a. V+ _) [potting material must penetrate into all parts of the transformer. The criteria ! m+ s* t7 ]* E6 \1 s" M1 H5 Ffor acceptance is the tests described in clause 26. The second edition of IEC ( J- c/ a+ y7 a- m) Q3 i7 Z61558-1 is clear in this respect.* ^+ p5 s: b1 P, p+ E! B
DSH 594/06( N! ~* g; J1 G0 {) V6 a