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ID glass cartridge fuses ???

peterlonz

Feb 11, 2010
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I am just putting together a fairly simple Power supply. 240VAC mains powered with DC - DC converter. Max output 24VDC.
Max current about 5A DC.
I have accumulated quite a number of glass fuses of various sizes. But now I come to choose the best rating & size for my job -Horror - I ca't read the damned info stamped on the end caps. Sure I can guess but I can't even tell slow from std blow nor in most cases the current rating.
How common is this problem?
Is there a solution?
What do most folks do?
If I can't read with confidence how Can I even check that my local parts supplier has got it right?
 

(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
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Jan 21, 2010
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You can pass an ever increasing current through them until they blow...

Are the markings unreadable, or is it that you can't read them?
 

davenn

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If I can't read with confidence how Can I even check that my local parts supplier has got it right?


do some sharp well lit photos of the text on the ends of a couple of them to us to see
 

peterlonz

Feb 11, 2010
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The markings I see are not sufficiently distinct that I can say with confidence what they are.
About half are clearly rated 250V, the balance seem to have zero info on voltage.
Some of the current ratings are reasonably clear But many are not.
I am using a jewelers magnifying glass to get a better view, I think its rated as X3.
Other markings can be seen but I have no idea if they are relevant.
I do not have a camera that would allow a clear image to post.
Why is this so, can't be that difficult to mark one end with v & A, other end could carry manufacturers ID.
How is slow / std blow normally marked?
 

(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
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You might expect to see something like

250V 5AT

For a regular 5 amp slow blow (T) fuse, or

125V 630mAFF

For a very fast blow (FF) 630mA fuse.
 

peterlonz

Feb 11, 2010
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Steve & others,
Thanks for the replies.
Withe the info provided, together with info from other posts on fuses, I think I can proceed safely.
I remain uncertain about fuses that carry only a current rating, with plain wire filament, what are these most likely to be?
I noticed on another post that many/most/some automobile fuses are rated at 32V & can be used in low voltage circuits. Is the 32V rating very common, none of my automotive fuses (several types) carry any voltage rating.
Again thanks.
 
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