108/207/INF：IEC 60950-1例行試驗(yàn)中的抗電強(qiáng)度試驗(yàn)要求

IEC 60950 Ed. 2 (subclause 5.3.2)

IEC 60950, Ed. 3 (subclause 5.2.2)

IEC 60950-1, Ed. 2 (subclause 5.2.2)

Background:

In Japan, there is some confusion with the application of the Electric Strength Test in production (as routine test) to the finished equipment, in the scope of IEC 60950-1. Japanese IT industry believes that it is common practice widely performed in worldwide for several decades, to apply the electric strength test with the reduced duration between 1 s and 6 s, with the test voltage in accordance with Table 5B in IEC 60950-1.

Recently, however, another interpretation has been discussed in Japan that although the practice used to be authorized based on the statement in the note in clause 5.3.2 of IEC 60950:1991 (2nd edition), it is not allowed anymore after the release of IEC 60950:1999 (3rd edition) or later editions, because the note in clause 5.2.2 is stated differently than 2nd edition and there is no description specifying how the routine test should be done elsewhere in the standard.

The following is the comparison among three editions:

Note 1 in Clause 5.3.2. (IEC 60950:1991 2nd Ed.): For production test purpose, it is permitted to reduce the duration of electric strength test to 1 s.

Note 1 in Clause 5.2.2 (IEC 60950:1999 3rd Ed.): For ROUTINE TESTS specified elsewhere in this standard, it is permitted to reduce the duration of the electric strength test to 1 s.

In IEC 60950-1:2005 (2nd Edition) this text has been made normative and reads as follows: Where, elsewhere in this standard, ROUTINE TESTS are required to be conducted in accordance with 5.2.2, it is permitted to reduce the duration of the electric strength test to 1 s and to reduce the test voltage permitted in Table 5C, if used, by 10 %.

It is widely understood that the electric strength test time needs to be controlled to short duration, because if test voltage is applied for longer time, partial discharges may occur in solid insulation, and cause undetected insulation damage. This can result in unnecessary insulation failures during subsequent product use, and shorten the product's life span, as this does not only apply to internal parts and components, but also to the complete equipment.

Questions to the Panel:

1) Is it the intention of TC108 that the requirements of IEC 60950-1 clause 5.2.2 is to accept the application of the electric strength test in the production (routine test), to the equipment, (including components or material) reduced to 1 s or not?

2) Also, in case it is acceptable, if the test voltage should be in accordance to Table 5B in IEC 60950-1 or not?

Opinion of the Panel:

1) Yes

2) Yes

108/207/INF簡要解析：

一般來說，抗電強(qiáng)度試驗(yàn)的持續(xù)時(shí)間要控制在較短的時(shí)間內(nèi)，因?yàn)槿绻┘雍荛L時(shí)間的高試驗(yàn)電壓，會在固體絕緣中形成局部放電，造成未被發(fā)現(xiàn)的絕緣損壞。這可能導(dǎo)致產(chǎn)品在后續(xù)使用過程中出現(xiàn)不必要的絕緣故障，進(jìn)而縮短產(chǎn)品壽命，這不僅針對內(nèi)部部件，也影響了整個(gè)設(shè)備。TC108的意圖是在生產(chǎn)過程的例行試驗(yàn)中，將抗電強(qiáng)度的持續(xù)時(shí)間縮短為1s，如果使用IEC 60950-1表5C的電壓，還可以降低10%。

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