In a message dated 10/17/2005 10:08:29 PM Central Standard Time,
tr3driver@comcast.net writes:
> Perhaps there is, but it involves a bunch of other variables not given. To
> get
> heat, you have to dissipate power, which is volts times amps (or, since the
> resistance of the fuse is relatively fixed and volts is amps times ohms,
> amps
> times amps times ohms). Once you know how much heat is being put into the
> fusible element, you need to know how fast it is being conducted away, and
> what
> the thermal mass of the element is. Armed with that information, you can
> estimate the temperature rise over time.
>
And don't forget to derate for ambient temperature.
The main reason for premature fuse operation is contact resistance in the
fuse holder (See Joe Pawlack's Fusinator demo) which effectively raises the
local
ambient temperature at the fuse.
Nothing is ever as simple as it appears.
Dave
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