Steve,
#30 is way too big. I use #40 for 1-1.2 amp. I'd suggest #38 for your 2
amp supply. The object of the game is to EASILY fuse the wire, not wire
your house with it.
Fine wire sizes can be easily obtained by stripping a piece of common
lamp cord. The fine strands are each in the range of 36 to 42 usually.
Take a sample from all of your discarded appliance cords and save a few
feet of several sizes.
Make sure you pull the wire tight and keep it 2" or less between
supports. I use some spring clip thingys on ceramic standoffs so that
if/when it blows I can just push a new piece of wire into the clips
without tools.
If the wire is sized correctly, it will fuse very fast and protect
everything. I've been using this system for many years on "problem"
tubes that like to arc. Never had any collateral damage occur due to an
"event" even when there was no glitch resistor present.
73,
Larry - W7IUV
On 16-Feb-10 3:59 PM, K1SG@aol.com wrote:
> In recent threads, there have been a number of comments about high voltage
> fuses.
> Carl mentioned sand-filled fuses, something I hadn't heard of.
> I checked the Mouser catalog for HV fuses, and was stricken with
> sticker-shock...$38 for a fuse?
> OK, we re-think this one...
> I know that an old but workable approach is to use a thin piece of wire
> as a fuse...mount it between a couple of standoff insulators, and it should
> function fine, and if current is substantially too high, the fuse wire
> blows. How do you figure the appropriate size wire to use? And then, how do
> you
> go about ordering 6" of #30 wire, or whatever it is? If you need more
> current capacity, to use the above example, can I put two strands of #30 wire
> in parallel, and expect them to function as a reliable fuse? I'm always
> worried about kinking the wire, or if it's enameled, sanding off more than
> just the insulation.
> The plan is to fuse the HV output of a 5KV 2A supply to a 3X3, which of
> course will only be used at the legal limit or into a dummy load.
>
> Steve Gilbert
> K1SG
> K1SG@AOL.com
> 508-435-9133
> FN42fe
>
>
> _______________________________________________
> Amps mailing list
> Amps@contesting.com
> http://lists.contesting.com/mailman/listinfo/amps
>
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
|