应用案例/解决方案/技术文档/选型指南

应用案例

专注于电路保护，为客户用电更安全

应用案例/解决方案/技术文档/选型指南

发布时间: 2025-03-28 17:13

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一、Fuse Selection保险丝选型步骤

➢Voltage Rating (AC or DC) / 额定电压(交流或直流)

➢Available Short Circuit Current / 最⼤故障(短路)电流

➢Full Load Current/ Current rating / ⼯作电流/额定电流

➢Ambient Temperature / 环境温度

➢I2t Characteristics of components protected / 被保护器件的I2t特性

➢Pulse and In-rush characteristics / 脉冲和浪涌特性

➢Physical Size / 物理尺⼨

➢Applicable Agency Standards / 安规认证

二、Voltage Rating额定电压

➢It’s safety issue, relate to the Breaking capacity (B.C.) or interrupting rating (I.R.)

额定电压是安全问题, 与分断能⼒相关

➢The voltage rating of a fuse must be equal to or greater than the circuit voltage.

保险丝的额定电压必须等于或⼤于电路电压.

➢Rating depend spacing of terminals.

电压值与端⼦间距相关

三、Available Short Circuit Current最⼤短路电流

➢The breaking capacity is the max available current, at rated voltage, that the fuse can safely operate at.

分断能⼒是保险丝在额定电压下能安全断开的最⼤电流.

➢ The breaking capacity (or interrupting rating) of a fuse must be greater than the total available short circuit current at rated voltage.

保险丝的分断能⼒必须⼤于额定电压下的最⼤短路电流.

四、Current Rating额定电流

➢The operating current is the maximum current in the circuit, under normal operation state.

额定电流指电路正常⼯作时的最⼤电流.

➢The ampere rating of a fuse is its current carrying capacity.

保险丝的额定电流是它的电流负载能⼒.

➢An operating current of 80% or less than rated current (of fuse) is recommended for operation at 25°C to avoid nuisance openings.

为防⽌保险丝意外开路, 建议保险丝在80%(或更低)额定电流下⼯作(25°C)

五、Ambient Temperature环境温度

➢All electrical characteristics of a fuse are rated and validated at an ambient temperature of 25°C.

保险丝的所有电⽓特性都是在25度室温下标定和确认的.

➢Re-rating is required for ambient temperatures lower or higher (temperature re-rating curves-EPS)

当环境低于或⾼于25度时, 必须重新标定额定电流(依EPS提供的降额曲线)

六、Overload / Operating Time过载/熔断时间

➢Described by % of rated current.

按额定电流的百分⽐定义

➢The first operating point described (varies by product) must be applicable, and the time to operate, appropriate.

所定义的第⼀个动作点(依不同产品⽽不同)必须是适⽤的, 并且动作时间是恰当的, 能够保护电路.

** Strongly recommend not use over load at 150% ~ 200% rated current.强烈建议不要让过载电流落在保险丝额定电流的150%~200%之间

七、Fuse Characteristics _ I-t Curve

➢ Time vs Current curves show how long it will take for a fuse to open given a specific current level.

时间电流曲线提供保险丝在特定电流下的熔断时间

八、Melting Integral I2t_Definition热熔值_定义

➢The melting integral, termed I2t, is the thermal energy required to melt a specific fuse element.

热熔值, 简称I2t, 是熔丝熔断所需的能量.

➢Two ways I2t is used to properly select a fuse in a specific application.

从两⽅⾯来确定保险丝的I2t是否合适

➢Components downstream often have a thermal withstand capability. Therefore, the I2t of the fuse must be lower than the I2t withstand of the downstream component.

保险丝后端的元器件通常有⼀定的热耐受能⼒. 因此, 保险丝的I2t必须低于后端元器件的I2t耐受能⼒.

➢ Surge or pulse currents are often normal in an application. The fuse must be able to withstand the thermal energy generated by the pulses and not cause nuisance openings.

电路中通常有浪涌或者脉冲电流. 保险丝必须能够耐受这些脉冲产⽣的能量⽽不造成意外的开路.

九、Physical Size物理尺⼨

➢ Select proper fuse type base on your application and space requirement: Ferrule,

ferrule with leaded wire, SMD (6125/1206/0603) etc.

依照应⽤和空间要求, 选择适当的保险丝类型: 管状, 管状带引线, 贴⽚(6125/1206/0603)

➢ Fuse size limited by circuit voltage(terminal space);

注意电路电压对保险丝的尺⼨要求有限制(端⼦间距)

十、Fuse popular for secondaryStandards 保险丝二级保护标准

➢ UR is most popular for secondary over current protection.

在⼆级过流保护中, UR是最通⽤的认证.

➢ These standards have different operating times and therefore not interchangeable.

这些标准有不同的动作时间, 所以保险丝不能随意直接替换