Jun 4, 2019 · A fuse will typically have two I 2 T ratings, a minimum withstand rating and a maximum let-through rating, and they are usually somewhat different values. The I 2 T rating of a fuse is a related to the energy it lets through to any given load by the resistance of the load .

Mar 19, 2018 · The I²t (Ampere Squared Seconds) also known as Melting Point in a fuse. The purpose of this rating is to assure that the heat created across the fuse during a surge has insufficient time to thermally conduct away from the fuse to external circuitry.

Aug 3, 2021 · The full formula for the time to fuse is: (k i2t / k i 2) ln(i 2 / ((i - k i)(i + k i))) Where k i2t is the i 2 t rating and k i current rating of the fuse.

Mar 19, 2018 · For time > thermal time constant self-cooling demands more energy to raise resistance times current^2 to reach melting temperature of metal conductor and open fuse. This is the steep curve for time > 0.1s. Fuses are rated for the holding current within a certain temperature range and not the breaking current.

The I2t passed by a given fuse is dependent upon the characteristics of the fuse and also upon the applied voltage. The I2t passed by a given fuse will decrease as the application voltage decreases. Unless stated otherwise, published I 2t values are based on AC testing. The It passed by a fuse in a DC application may be higher or lower than in

i2t is an expression of thermal energy that results from current flow. In fuses, this expression happens in: Melting i2t – The current required to melt a circuit; Arcing i2t – Thermal energy passed by a fuse during arcing. Total clearing i2t – The time from overcurrent inception until complete interruption.

This technical document describes how Eaton utilizes an I2t test in its Cooper Power series products to verify and guarantee that every current-limiting fuse produced will meet their published minimum melt I2t levels and will not operate prematurely.

Each fuse series and ampere rating utilize different materials and element configurations; therefore, it is necessary to determine the I2t value for each fuse. Tests to determine the I2 t of a fuse are the rated current with a time constant of less than 50 microseconds in a dc test circuit.

DERIVATION OF NOMINAL MELTING I2t: Laboratory tests are conducted on each fuse design to determine the amount of energy required to melt the fusing element.This energy is described as nominal melting I2t and is expressed as “Ampere Squared Seconds” (A2 Sec.).

Jan 17, 2021 · How do I convert the fuse current rating to the i2t value? For example, in this circuit simulator, when adding a fuse, the only values that can be specified are the i2t value and resistance. The f...