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Keysight New instruments
bd139:
A scope is not a multimeter or a spectrum analyser either. But it’s a good compromise. Which is the point of a power supply.
bdunham7:
--- Quote from: NANDBlog on March 09, 2021, 08:29:12 am ---No. A large lithium battery can easily supply 1000A if short circuited. You would need a fuse with 1000A DC breaking capacity.
--- End quote ---
That would be a standard AGC glass fuse at 32VDC, with sub-millisecond fusing time. And even with an 8S pack of 'huge' batteries, the combined series resistance of the battery, wires and crowbar circuit including traces would have to be 32mR or less for 1000 amps to flow for that millisecond.
--- Quote ---Fast acting, because you want to protect semiconductors with it. And then you realize that fuses are not meant to be used to protect semiconductors...
--- End quote ---
That's a pretty broad statement, especially considering the range of products that are called 'semiconductors'. Fuses can--and commonly do--protect semiconductors just fine in a properly designed circuit, with obvious limitations. For a crowbar, if the impedance of the crowbar is just high enough so that the peak current doesn't exceed the SCR peak rating (which can be 1000 amps without using anything extraordinary) then the fuse just has to blow before the SCR melts. Not difficult at all to understand or design.
--- Quote ---A power supply is not a charger.
--- End quote ---
Again, a very broad statement. Mine are suitable for battery charging. It says so in the manual. They don't use a crowbar for OVP though, that seems to be suboptimal for battery charging. Actually, to me it seems suboptimal in general.
tszaboo:
--- Quote from: bdunham7 on March 09, 2021, 05:34:26 pm ---
--- Quote from: NANDBlog on March 09, 2021, 08:29:12 am ---No. A large lithium battery can easily supply 1000A if short circuited. You would need a fuse with 1000A DC breaking capacity.
--- End quote ---
That would be a standard AGC glass fuse at 32VDC, with sub-millisecond fusing time.
--- End quote ---
I'm sorry to tell you, but the only information in your comment is that you dont understand the rating of fuses. Look up the difference between AC current rating, and DC current rating of a fuse, and why they are different.
https://www.eaton.com/content/dam/eaton/products/electronic-components/resources/data-sheet/eaton-agc-fast-acting-glass-tube-fuses-data-sheet.pdf
Before you start searching for it: No it doesnt have a DC rating at all. Moving on.
bdunham7:
--- Quote from: NANDBlog on March 09, 2021, 10:40:42 pm ---I'm sorry to tell you, but the only information in your comment is that you dont understand the rating of fuses. Look up the difference between AC current rating, and DC current rating of a fuse, and why they are different.
--- End quote ---
Condescending snark isn't helpful. I fully understand why AC and DC interrupt ratings are often, but not always, different. But I think the datasheet you posted has some errors, unless you would like to explain why a fuse current interrupt rating would go down with a lower voltage--if you can explain that I would truly learn something. Here is the previous version:
https://www.grainger.com/ec/pdf/6F018_1.pdf
Fuses in automotive applications, especially 24/28 volt systems in larger vehicles, have to deal with some pretty high fault currents and they use AGC (old) and ATO (new) plain fast-blow fuses without any trouble. I think 1kA was pretty standard for 32VDC AGC fuses although I don't have a datasheet handy, and I don't think it makes much difference if it is AC or DC. (Perhaps you can guess why?) If that's not convincing or if you demand an explicit DC interrupt rating in a datasheet, just find a different fuse with the rating you want.
https://www.mouser.com/datasheet/2/240/Littelfuse_Fuse_314_324_Datasheet_pdf-756861.pdf
Edit: and here is a datasheet for a modern automotive-style ATO fuse that explicitly states 1kA@32VDC
https://www.mouser.com/datasheet/2/240/Littelfuse_ATOF_Datasheet-523209.pdf
ResistorRob:
Nobody has posted the teaser video?
I really like the interconnectivity between instruments and available apps for each instrument.
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