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标题: 关于热熔断器Thermal link温升测试疑问---怎样判断其温升通过？ [打印本页]

作者: jason1031 时间: 2011-12-23 18:53
标题: 关于热熔断器Thermal link温升测试疑问---怎样判断其温升通过？
热熔断器有三个主要参数：
Tf断开温度functioning open temperature，Th保持温度holding temperature, Tm最大过冲温度maximum overshoot temperature UL标准中，热熔断器英文描述为thermal cut off，但iec标准则描述为Thermal link。

热熔断器于正常温升测试中，是按照A: 热熔断器表面测的最大温度低于Tf-25,还是按照B: 热熔断器表面温度低于Th保持温度？按何标准判断通过热熔断器正常温升测试？

例如，规格为Type G4A00-216, rated 120 V, 15 A, function temperature 216?C, 保持温度holding temperature为200?C, 按照A执行Tf-25=191?C<保持温度200?C，可以理解。

但规格为 G4A00-240, rated 120 V, 15 A, , function temperature 240?C, 保持温度holding temperature为同样是200?C。如果同上按照A执行Tf-25=215?C>保持温度200?C，此温度高于保持温度holding temperature 200?C,显然不对，因为这样存在热熔断器表面温度高于保持温度的可能，对于将危害到成品机器的可靠性。

是否采用A及B的交集来判断？Tf-25，Th中那个最低采用那个？有何标准来支持？

作者: feazhp 时间: 2011-12-23 18:53
专业！能解释一下什么是holding temperature 吗？

作者: orlzvs 时间: 2011-12-23 18:53
热熔断器,具体测试起来问题也是很多，按照标准的方法，执行起来有点困难，希望哪位高手能指点下呢

作者: 网络营销bc 时间: 2011-12-23 18:53
如果楼主真的想知道，请提供一份证书，我给你解释，如果上面的参数是厂家提供的，那就抱歉了，因为如果没有定义，是很难确定其实际意义的，证书上的参数可以从标准上找到定义及其是如何测试和得出的。

作者: jason1031 时间: 2011-12-23 18:53

原文 :
专业！能解释一下什么是holding temperature 吗？

Rated functioning temperature(Tf)： The temperature at which a Thermal Cutoff changes its state of conductivity to open circuit detection curret.The tolerance according to IEC60691 is from +0 to-10℃

Fusing(cut)-off temperature： The fusing-off temperature indicates value measured in silicon oil with a temperature increased by 0.5-1℃ per minute and a detective current 100mA or less.

Holding temperature(Th)： The maximum temperature at which a thermal Cutoff will not cause a change in state of conductivity to open circuit while conducting rated current for 168 hours. This rating is required by safety standards based on IEC60691.

Maximum temperature limit(Tm)： The maximum temperature at which a Thermal Cutoff can be maimtained for 10 minutes without reclosing.This rating is requirde by safety standards based on IEC60691.

作者: 小李子子 时间: 2011-12-23 18:53
指出下：
thermal cut off与Thermal link是个概念！以下是对三个概念的解释
EN60335中
3.7.3
thermal cut-out
device which during abnormal operation limits the temperature of the controlled part by
automatically opening the circuit, or by reducing the current, and is constructed so that its
setting cannot be altered by the user
3.7.7
thermal link
thermal cut-out which operates only once and requires partial or complete replacement
在UL1026中
26.5 A thermal cutoff that is provided as a temperature-limiting device shall comply with the
applicable requirements in the Standard for Thermal-Links – Requirements and Application
Guide, UL 60691.

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