7 K; o0 H* \! _% p9 u! i我刚见过这么一个结构,是PTC取暖器,取暖器出风开口看进去,能看见裸导体,导体前面覆盖一个接地了的金属丝网,金属丝网非常软,但是下衬一个塑料框架保证接地丝网和裸导体之间爬电距离和电气间隙,我用30N的压力压丝网,发现还是能保证爬电距离和电气间隙的,但是我现在担心这个接地丝网通不过冲击实验?但是开口又刚好挡住了弹簧冲击器的头作者: kendy 时间: 2007-6-26 09:46
关键是41号探棒能触到发热元件，但因空间太小挡住了弹簧冲击器，致使它不能冲到石英管，只能冲到它周围的结构件。作者: seasunsky 时间: 2007-6-26 09:54
一般来说，PTC暖风机的出风口栅格材料都比较脆，因为该处温度比较高，§30章试验对材料的需要。如果接地金属网在出风口栅格之后，而出风口栅格可以经受冲击试验，个人认为没必要再去想着冲击接地金属网了，毕竟弹簧冲击器的头也进不去。主要还是看其爬电距离、电气间隙能否满足，以及接地金属网的接地是否良好，因为有时候企业为了防止金属网生锈，喷漆很厚，接地处未刮漆且不采用梅花垫圈，很难保证接地良好性作者: seasunsky 时间: 2007-6-26 10:06
刚才发错图勒 / _6 }& |# Y% V/ V. Q你看注2上面那个对冲击区域尺寸的要求8 C2 C' u8 N" S0 g& U3 ]. P/ U
看其是否符合作者: barry 时间: 2007-6-26 11:09
21 Mechanical strength1 Z( F; v. U/ U1 g1 [; |: ?% O
21.1 Appliances shall have adequate mechanical strength and be constructed to withstand such rough handling that may be expected in normal use.' o% F) a8 U: r# _+ `: T$ h, `' }
Compliance is checked by applying blows to the appliance in accordance with test Ehb of IEC 60068-2-75, the spring hammer test.$ D* a. @9 o5 l! w w
The appliance is rigidly supported and three blows, having an impact energy of 0,5 J, are applied to every point of the enclosure that is likely to be weak. / R" ?7 t9 ?9 b( LNOTE 1 Void. : s5 m" R' O# S1 p' r4 xIf necessary, the blows are also applied to handles, levers, knobs and similar parts and to signal lamps and their covers but only if the lamps or covers protrude from the enclosure by more than 10 mm or if their surface area exceeds 4 cm2. Lamps within the appliance and their covers are only tested if they are likely to be damaged in normal use. 8 y4 v, ^6 U" h Q- UNOTE 2 When applying the release cone to the guard of a visibly glowing heating element, care is to be taken that the hammer head passing through the guard does not strike the heating element. 3 c/ w9 R5 {/ ~ kAfter the test, the appliance shall show no damage that could impair compliance with this standard and compliance with 8.1, 15.1 and clause 29 shall not be impaired. In case of doubt, supplementary insulation and reinforced insulation are subjected to the electric strength test of 16.3. & K" l8 o) S8 W" ^7 zNOTE 3 Damage to the finish, small dents that do not reduce clearances or creepage distances below the values specified in clause 29, and small chips that do not adversely affect protection against access to live parts or moisture, are ignored. ) ~( M- ~- i( c' P( L" TNOTE 4 If a decorative cover is protected by an inner cover, fracture of the decorative cover is ignored if the inner cover itself withstands the test. ! |% R' d- c% ~6 M# r3 aIf there is doubt as to whether a defect has occurred by the application of the preceding blows, this defect is neglected and the group of three blows is applied to the same place on a new sample which shall then withstand the test. 8 T; ]8 J% _ W, m3 U! O' eNOTE 5 Cracks not visible to the naked eye and surface cracks in fibre-reinforced mouldings and similar materials are ignored. : S3 b7 ?7 Z) L( m4 |7 W3 E9 v ' w8 C0 x. Y3 z( P& _5 } e6 Ghehe, 想和大家讨论一下冲击测试。。。作者: kendy 时间: 2007-6-26 13:44
现在情况是41号探棒能触到发热元件，冲击区域也大于4平方厘米，只是冲击器正好被内腔稍挡了一点，就冲不到石英管。作者: seasunsky 时间: 2007-6-26 13:54
最好给个图看看作者: jeanson 时间: 2007-8-26 23:14
做电暖器是要经过周密测试的，安全很重要。我同意6楼的看法，但是不全对，要考虑前面的网不能是脆的，必须用强度高的塑料如PBT+30%GF类的。作者: kendy 时间: 2007-8-27 11:33