自恢复保险丝型号汇总(3)

本文档是某国际大品牌公司的产品手册,汇集了自恢复保险丝的所有型号。在设计过程中可以用来选型,画器件封装,计算参数等等。

- FUNDAMENTAL II

HOW DOES THE RESETTABLE FUSE WORK

FUZETEC resettable fuses are designed and made of patented novel polymeric PTC material in thin chip form, developed solely by FUZETEC . With electrodes and leads attached on both sides, it is placed in series to protect a circuit. At “normal operating condition” the device remains at an extremely low resistance (milli-ohms) and allows the electrical current to flow through it without any restriction. When overcurrent conditions occur, the polymeric PTC material heats up and its resistance increases sharply. Such a sharp resistance increase (to an insulated status) cuts off the current in the circuit, and consequently protects the element and device in the circuit. Upon fault current being removed, the resettable fuse cools and its resistance drops to the original extremely low value. The resettable fuse is “reset” and allows the current through the circuit again.

TRIP CURRENT, HOLD CURRENT AND THERMAL DERATING

Trip Current (IT) and Hold Current (IH) of FUZETEC resettable fuse are rated at 23℃. Typically its Trip Current is twice as much as its Hold Current. FUZETEC device does not trip at or below its rated Hold Current, and will trip at or above its Trip Current value. However, due to PTC effect both IT and IH reduce with ambient temperature increase and vice versa. As shown bellow, the currents are reduced nearly 50% at 85℃ and increased to 150% at -40℃.