Don't Try This At Home! - Testing fuses Part 2

[FOX]

Hi Martin,

nice Video as always.
The fan you used to cool the DC-Load seems to suck the hot air away from the heatsink, if you turn it around so that it blows the cool air onto the heatsink you should get much lower temperatures on that heatsink.

Fuses in general are a rather coarse method for overcurrent protection and are mainly meant to protect from high peak current (e.g. shorting something inside the device). They are not designed to blow exactly on their rated current, have a look at the datasheet i linked below.
http://www.littelfuse.com/data/en/Data_Sheets/299.pdf
So it's not surprising that you can push almost twice the rated current throu your fuses, if you cool then with your fan you should be able to push it even a little farther. Altough they should not melt before the blow.

Fuses seem decptive simple but their one need a fair bit of know how to make save and reliable fuses and thats why the "good" fuses aren't cheap.

P.S. I envy you to have a thermalimager to play around 

[Kiriakos GR]

Link of the video.  http://www.youtube.com/watch?v=S5LVHoUXerk

Martin you did not set the Emissivity factor on the camera, 
aluminum haves a specific Emissivity factor, and so your temperature  measurement is far out.

[MJLorton]

Hi Martin,

nice Video as always.
The fan you used to cool the DC-Load seems to suck the hot air away from the heatsink, if you turn it around so that it blows the cool air onto the heatsink you should get much lower temperatures on that heatsink.

Fuses in general are a rather coarse method for overcurrent protection and are mainly meant to protect from high peak current (e.g. shorting something inside the device). They are not designed to blow exactly on their rated current, have a look at the datasheet i linked below.
http://www.littelfuse.com/data/en/Data_Sheets/299.pdf
So it's not surprising that you can push almost twice the rated current throu your fuses, if you cool then with your fan you should be able to push it even a little farther. Altough they should not melt before the blow.

Fuses seem decptive simple but their one need a fair bit of know how to make save and reliable fuses and thats why the "good" fuses aren't cheap.

P.S. I envy you to have a thermalimager to play around 

Thanks Fox,

Very valuable input. All these points you make and the comments from the videos I hope to bring together in part 3.

And yes....I'd love to be able to keep the thermal imager...but it has certainly been fun playing with it!

Cheers,
Martin.