New fuse for Astron 35?

Discussion in 'General Technical Questions and Answers' started by KM6LYW, Dec 21, 2018.

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  1. W9KEY

    W9KEY XML Subscriber QRZ Page

    We must be careful to define our terms here. It may indeed be sound practice to only operate a fuse at 75-80% of it's rated current to avoid long term nuisance tripping - but that's a different matter (similar to derating capacitors below their stated voltage). Here are a few examples, and I'll certainly read any Data Sheets you provide to the contrary:

    DigiKey Fuse Tutorial: "The current rating is the maximum current that can flow through the fuse under normal conditions. Fuses will typically be de-rated at 25% to avoid nuisance blowing at 25˚C".

    Schurter Fuse Selection Guide: "A fuse, which is designed according to IEC standard, can continuously operate at 100% of rated current of the fuse. A fuse, which is designed according to a UL standard, can continuously operate at 75% of rated current of the fuse."

    Littlefuse Normal Operating Current: "The current rating of a fuse is typically derated 25% for operation at 25ºC to avoid nuisance blowing."

    So it might be a matter of semantics, but I'll stand by my original statement - which basically said a 1 amp rated fuse will carry 1 amp forever at 25 degrees C. But certainly a host of factors can be used to justify derating under practical applications, including: temperature, peak inrush currents, vibration, type of fuse holder, etc.
  2. W9WQA

    W9WQA Ham Member QRZ Page

    of all the complex electronic components, it continues!!!
  3. KA9JLM

    KA9JLM Ham Member QRZ Page

    When a fuse blows it is really a nuisance when you do not have a spare. :mad:

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