Fuse failures

[nukeman]

Does anyone have a good link for fuse failure analysis? I am looking for a site that describes fuse failure characteristics. In particular, I am evaluating a Gould-Shawmut AX25-40.

 

[electricpete]

I would be interested to see a site like that as well. I have had a few fuses sent to a lab for analysis. Usually the do an X-ray first, then open it up. The type I have seen usually have about 8 necked-down locations in an element by design. The more of the 8 are burnt thru, the higher the overcurrent. Only one burnt probably means only slight overcurrent. Also they look at sand melting as indication of the degree of overcurrent. Also look for cracks as sign of long-term thermal cycle fatigue.

That's what little I know about the subject. I'm sure you want more. Anyone have any links?

 

[Foxfur]

Here's a good technical document outlining the analysis and testing of fuses in lo/no-G, vacuum, harsh environments.

http://www.aem-usa.com/pages/press/OOPSC74.pdf

Foxfur

 

[Teflon]

Nuke,

Gould has software out there for fuse selection / info. It includes Let-Thru Data and Curves. Check out:

http://www.gouldshawmut.com/resources/selectafuse.html

 

[nukeman]

Teflon,
Thanks for the information. What I was really trying to find was information on fuse failures and how to distinguish between a short circuit fuse blow and an over load fuse blow.

The GouldShawmut site you referenced has good fuse information as does the Bussmann site. In particular, look at the Bussmann Electrical Protection Handbook. Another good reference is Electric Fuses, 2nd Edition by A. Wright and P.G. Newberry.

 

[busbar]

"...a short circuit fuse blow and an over load…"

Purely anecdotal "old bastard" advice: if the fuse is warm to the touch, the overload segment of the fuse operated. Obviously, evidence fades relying on this method. If the fuse is cold, the high-speed/short-circuit segment opened the circuit. [This may apply only to dual-element fuses.]