Meters and Microamps

[sam_sam_sam]

Re: Meters and Microamps

There are Fluke multimeters for sale where someone bridged the fuse... really common with automotive techs on 12V systems... the shunt and bridge rectifier get burned badly, tons of smoke.

Siba are excellent fuses but too they're snobby to have distribution in North America.

I wonder if HiFi-Tuning fuses would work? Gold-plated, none of this ugly overpriced Bussmann stuff. The diode symbol contains the electrons.
"ceramic casing, rather than glass, for better resonance characteristics"
"-196ºC cryogenic immersion bath treated for maximum clarity"

Same price as the Bussmann

The KTK-R-1 is even faster acting than the KTK-1 I have used both before and if I was going to use a fuse for my Fluke meter I would recommend using the KTK-R-1 they cost about $20 to $25 each depending where you buy them the only issue is that the KTK-R- series does not have as many selections to choose from as the KTK- series does ( but I would use either one and limit the amount of voltage I would check to 480 volts with this fuse )

I send “ Siba ” and email for some samples of there 1000 volt 1 amp fuses and asked them where I can buy them from ( I will post there respond in general when I get a response )

I have in the past ordered from Element 14 Great Britain before which has them in stock but it’s a small issue about doing it

[sam_sam_sam]

Re: Meters and Microamps

I send “ Siba ” and email for some samples of there 1000 volt 1 amp fuses and asked them where I can buy them from ( I will post there respond in general when I get a response )

I did get a response from them for a vendor that not very far from where I live

So when I am ready to buy some of there fuses I will give them a call and probably would have to order them I doubt that vendor would have them in stock

[eccerr0r]

Re: Meters and Microamps

The KTK-R series has a diode in it ...

So much for making holders that rejects anything but specific fuses, but yeah it looks like the KTK-R will blow at rated current even, after a little while. The KTK fuse without R will pass the rated current indefinitely.

[redwire]

Re: Meters and Microamps

KTK-R have the end bump (spring inside?) 600VAC 200kA fast interrupting capacity. USD $27
The curves look better, the 10A blows at 20A just under 1 second and carries 15A forever. What you'd expect.
The multimeter fuses are 1,000V but so slow.

[sam_sam_sam]

Re: Meters and Microamps

So you for a fuse that carry the current you are looking but find one that blows at the current you want to protect it from

But only use those charts as a guide because what they have is not exactly right because I had an issue with a VFD drive that I wanted fast acting fuses in it and I tried to use that chart and found that it would blow some what sooner than I expect them to ( this was because of the inrush current not being exactly the same each time the motor would start

For this type of application for a multi meter it might be more accurate but some testing would be in order to make sure that the results you get you expect

[stj]

Re: Meters and Microamps

i could never pay 2digit numbers for a fucking fuse.
i would rather change the clips from 10mm to 6.3mm or even try to gut a 10mm fuse to see if the internal diameter is enough to slot a 6.3mm fuse inside it!!

[sam_sam_sam]

Re: Meters and Microamps

i could never pay 2digit numbers for a fucking fuse.
i would rather change the clips from 10mm to 6.3mm or even try to gut a 10mm fuse to see if the internal diameter is enough to slot a 6.3mm fuse inside it!!

When you do this please post some pictures of this modification I would be interested in what you come up with

[stj]

Re: Meters and Microamps

i was just thinking of ripping an endcap off and putting a spring in it to tension the shorter fuse.
i got the idea because i'v had fuse endcaps pull off by accident in the past.

[eccerr0r]

Re: Meters and Microamps

i could never pay 2digit numbers for a fucking fuse.
i would rather change the clips from 10mm to 6.3mm or even try to gut a 10mm fuse to see if the internal diameter is enough to slot a 6.3mm fuse inside it!!

Please include carnage from trying to pass 100kA and it fails to rupture

TBH I had a unshrouded clip type ¼x1¼ fuse holder (one that's on a small hard piece of plastic with faston connectors on both sides) and the outside diameter of the clips perfectly fits inside the 10mm. Perfect jury rig!

(and it would happily pass 100kA until the smoke comes out...)

[stj]

Re: Meters and Microamps

if you really need a 1000v fuse that can break the output from a power station then your probably using the wrong meter for the job.
go buy a Hioki with the seperate current-clamp!

[eccerr0r]

Re: Meters and Microamps

Fuse stuffers! ... like cap stuffers!

Was seeing if this old burned buss fuse's caps would come off easily... nope...ugh.

BTW it doesn't sound like this 4A one I'm playing with right now is sand filled, and it's 10kA IR.

[stj]

Re: Meters and Microamps

new plan:
drill the endcaps and poke a length of fusewire through it - then solder the ends

[redwire]

Re: Meters and Microamps

I could not find much for "fuse adapters". The really old appliance/house screw-in glass fuses, guess who came up with a custom socket size? Good ole Bussmann. He seemed hell bent on making fuses tamper-proof... and proprietary.

I'm not sure how the end-caps are attached on ceramic fuses, it must be heat but that would melt the element. Melamine uses a hard crimp.

[eccerr0r]

Re: Meters and Microamps

I'm not sure I want to throw out the rotten caviar (the burned out fuse) yet... what else can I do with it before it goes into the round file?

[stj]

Re: Meters and Microamps

drill it

[redwire]

Re: Meters and Microamps

If you drill a hole, that assumes the new fuse-wire can be soldered, and I'm not sure if it's some low temp alloy.

It looks like heating up fuse endcap with a soldering iron or on a stovetop element can free it up. Wearing safety glasses. There's no glue because that can't take 1,000C high temperatures.

https://www.instructables.com/commun...ll-glass-fuse/

I see many fuses made with the end-wire just folded over the ends.
Apparently as long as the wire passes through the tube diagonally so the sand can quench the middle portion.

The crimped Melamine fuses, I think they would not be something you can diassemble, I have to look at Voltlog videos see how he did it.

[eccerr0r]

Re: Meters and Microamps

I would think glass needs to be glued, maybe with CA glue and hence heat will free it up. The running temperature of fuses doesn't need to be 1000°C all the time like a light bulb, so that should be fine. Can't be crimped as the glass will not like it. I've seen some where it has two caps that have holes in them - and the fuse wire really is simply soldered in place.

These caviar fuses are melamine or something like that and most people I see has cut off the cap, which defeats the purpose *sigh*

[stj]

Re: Meters and Microamps

glass fuses are glued with that brown stuff they use to hold the cap on lamp bulbs.
ceramic fuses are press-fit or they have kind-of crimped the inner edge probably by spining it between some rollers.

the fiberglass ones are crimped into the glass-mat and you wont get one open without cutting the end off the cap.
not that you have anything to lose doing that.

[stj]

Re: Meters and Microamps

btw, i see fluke charges about $150 for a 320x240 monochrome lcd display for their high-end meters.
keeping in mind a 320x240 colour IPS display of similar size from china is about $8 they are clearly just out to fuck meter owners at every opertunity.