Re: Meters and Microamps
Now where to get cartridge cases and do you have a beach resort that you can steal lots of sand from...
Now where to get cartridge cases and do you have a beach resort that you can steal lots of sand from...
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Re: Meters and Microamps
Glass-cloth reinforced Melamine G9 tubing, $28/ft or $3.50 per fuse, it's easy to crimp. Cost is double that of ceramic, with USA suppliers. So this looks like the bulk of the fuse cost.
The silica sand is around 40 grit. My math you need about 5gms each so a 50lb (22.7kg) sand bag is good for making 7,600 fuses. That's 500 fuses per $1 for sand costs.
A 500gm roll $20 of 36SWG 0.2mm tinned copper wire 1,790m good for 35,236 fuses,. That's 1,762 fuses per $1 for wire costs.
I looked at material costs because I want to sit on the beach sipping Mai Tai's like McAfee did before he went nuts.
Henry Bussman patents the cartridge fuse in 1919. I looked and fuses are heavily patented and getting worse with the new HVDC need in electric cars. It might explain why they are stupid expensive from legit manufacturers.Comment
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Re: Meters and Microamps
So sipping Mai Tai's on the beach is looking like it's being patented away? :-(Comment
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Re: Meters and Microamps
What is truly amazing to me ... is that you two can carry on so long over fuses ...sigpicComment
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Re: Meters and Microamps
What do you expect when the cost of this type of fuse got to cost that much money I would rant have a fit over it as well because I have a Fluke meter as well I hope I never need to replace a fuse because of some careless mistakeComment
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Re: Meters and Microamps
Come on join the fun there's 4 of us making pot shots at Bussmann, Siba, and Littelfuse shaking an angry fist at them.
And measuring the current draw of a capacitor charging up was a mistake...Comment
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Re: Meters and Microamps
OP, a replacement fuse for your Fluke 17 costs about 1/3 the price of the multimeter USD $50 at Digi-Key. It's absurdly priced for something made of a dollar of materials.
So in come the chinese counterfeit fuses, cost a few dollars but high resistance and who knows how they work.
We're trapped between decent quality over 10x the price, and cheap chinese counterfeits.
Eaton Corp. stock, $55B in market cap and record profits, stock doubled in 2 years. They'd scooped up Bussmann.Attached FilesComment
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Re: Meters and Microamps
Damn. Should have bought ETN last year. Luck does not exist for me. Including a burned out fuse to replace, no less.Comment
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Re: Meters and Microamps
so there are actually 3 solutions.
1: import SIBA fuses from europe at about $7 each.
2: import Australian fuses from Davy Jones in a mixed pack of 10.
3: buy a length of 10mm copper tube and cut it into 38mm lengths, then let natural selection take it's course.
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Re: Meters and Microamps
don't forget the foil wrap!
Also, though .223's will fit in 3AG slots, not sure if 9's will work for 5AG...Comment
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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
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Re: Meters and Microamps
a cartel formed a perpetual "shortage" of multimeter fuses as far as I can tell.
Slow blow and regular fuses markets are just fine...can even get them from hardware stores including the orange store.Comment
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Re: Meters and Microamps
Orange store = Home De(s)pot, and yes they sell 10mmx38mm slow blow fuses for building electrical use.Comment
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Re: Meters and Microamps
Well... I bought and got a 15A FF "chinese fleabay caviar" for my Fluke. Too bad it's impossible to test it for authenticity so I just stuck it in instead of having my fluke in limbo missing full functionality.
Says Made in Mexico so it might be mexican caviar.Comment
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Re: Meters and Microamps
You can shake it to hear the sand inside, or simply weigh it.
Measure its resistance to see if the element is reasonable. For sure they sub aluminum which gives higher resistance and the fuse would run hot when operating near it's 10A limit. The (Bussmann) fuse will dissipate about 1.5W and a chinese knockoff is much worse... what's a little melted plastic around the fuse and a warped multimeter case lol.
It's strange these multimeter fuses really don't blow until a lot of current is flowing - the 11A clears 50A at 5 seconds, at 20A after a few minutes.
The 440mA clears 1.5A at ~3 seconds, at 1.25A after a few minutes.Comment
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Re: Meters and Microamps
Well, they could have a little more sand to replace a little less fuse wire... or vice versa...
I think I will have to take my chances.
Surprised however when that 4A fuse burned almost instantly on my B&KP DMM when trying to measure capacitor charging current (which turned out to be quite large...). Capacitors are shorts after all, to charging transients...Comment
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Most analog meters are actually current driven - a current is needed to deflect the pointer full scale. They can be lots of different values. There are ones that can take several amperes to swing the pointer as they have internal shunts.
On the other hand there are many that are rated in microamps for the intent that they draw as little power as possible from the devices under test. Some are 1mA, 500µA, 200µA, 100µA, and the ubiquitous 50µA frequently used in analog VOMs. There are even 20, 25, 30 µA and even down to 10µA. Been collecting a bunch of different ratings and... -
I read EBOOK of Testing Electronic Component and found that
"In order to test the small blue resin coated ceramic disk capacitor which has 104 50v specification,it is possible to test this small ceramic capacitor by making use of analogue meter.
Set to times 10Kohm that has 12v output from the probe to check disorder of ceramic capacitor.
It is not uncommon that testing result of digital capacitance meter is okay,But It show shorted reading when you check it with analogue meter."
Is it really possible to test small ceramic disc capacitor with analogue... -
Hi
I want to change the scale of an analog meter, to monitor the charge of an li-ion single cell, so the needle at the end would point 4.2 volts and the 0 on the meter would point 2.5 volts or so, i tried to add diodes or a zener in series with the meter but the changes of the ambient temperature also changes the voltage value on the meter
I wonder how i can accomplish this so the meter would be precise at any temperature ?
Thnaks -
About a month ago we had a transformer jumper wire that burned in two different places between two transformers caused over $200 thousand dollars worth of damage to VFD drives at least 10 of them and a memory card and quite a few power supply as well
Now we have most of the equipment that got damaged back up and running except a feeder that has issues and we are waiting for some parts for
Now we also have another piece of equipment that was blowing fuses on the 110 volt controller switch circuit with the “E” stops and one switching power (24 volt) supply and a transformer... -
I have had with regular AA batteries that leak this meter is expensive new I already replaced the battery battery clips once and the same thing happened again and I am tried of so it is getting modified to accommodate lithium ion batteries that are the same size excluding the positive terminal and removing the battery clips I will have enough room for the BMS protection board
I going to put 3 lithium ion battery in parallel with the BMS protection board and a way to charge the battery externally and heat shrink the battery pack and use a JST connector so I easily remove the battery...
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