Re: [Amps] Fuses

[Ian White GM3SEK <gm3sek@ifwtech.co.uk>]

James R Carr wrote:
>Where pray tell do you get a hydraulic breaker? I have installed 
>several thousand over the years but have yet to see one filled with 
>oil. As for current limiting devices, the fastest breaker will hold in 
>for three to seven full cycles. To be current limiting, a fuse has to 
>clear in less
>than 1/2 cycle.

A fuse provides NO current limiting until it blows; and a breaker 
provides NO current limiting until it breaks.

A lot of damage can be done in those first few milliseconds, which is 
why the fuse/breaker is only PART of the solution.

We always need a surge limiting resistor in the B+ as well, to provide 
instantaneous current limiting until the fuse/breaker takes over and 
finally breaks the circuit.


-- 

73 from Ian GM3SEK
http://www.ifwtech.co.uk/g3sek
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