Cheaper to run a polyfuse...why bother asking???

Josh Luthman
Office: 937-552-2340
Direct: 937-552-2343
1100 Wayne St
Suite 1337
Troy, OH 45373

On Mon, Mar 21, 2016 at 4:01 PM, Chuck McCown <[email protected]> wrote:

> Still leaning toward the polyfuse.  Not a lot of room, fuses and fuse
> holders are more money.
>
> *From:* Bill Prince <[email protected]>
> *Sent:* Monday, March 21, 2016 1:51 PM
> *To:* [email protected]
> *Subject:* Re: [AFMUG] Fuse question
>
> Most of ours are now the DIN-mounted double feed that uses the 5x20mm
> glass fuses. However, we also have a few legacy sites that use the
> automotive blade fuses.
>
> If something new came along, we would use what it uses.
>
> bp
> <part15sbs{at}gmail{dot}com>
>
>
> On 3/21/2016 12:47 PM, Josh Luthman wrote:
>
> We already stock 5x20mm fuses so keeping with the same form factor would
> be nice.  Anyone else using those same DIN clip fuse holders have the same.
>
>
> Josh Luthman
> Office: 937-552-2340
> Direct: 937-552-2343
> 1100 Wayne St
> Suite 1337
> Troy, OH 45373
>
> On Mon, Mar 21, 2016 at 3:40 PM, Adam Moffett <[email protected]> wrote:
>
>> I have no strong opinions sir, but if it's a replaceable fuse I do like
>> the automotive blades because every gas station has them.
>>
>>
>> On 3/21/2016 2:42 PM, Chuck McCown wrote:
>>
>> I am considering adding a fuse to a new version of my rack mount POE
>> surge suppressors.
>>
>> I know many of you like PTC resettable solid state fuses.  I don’t
>> recall ever designing one in to anything.
>> Maybe I did on a phone device years ago, but that would have been to
>> satisfy a regulatory agency only.
>>
>> Studying up on them I learn that if you have a 1 amp “hold current” the
>> “always trip” current is 2 amps.
>> Not like a fuse, which is pretty well guaranteed to trip at any current
>> over the rating if you wait long enough.
>>
>> For a polyfuse, if your load is one amp, you have to have a design value
>> of greater than 1 amp hold current.
>> But then it takes double that to actually trip..
>>
>> And then there is leakage current required to keep it in the tripped
>> condition.
>> It does not totally break the circuit.
>>
>> They are fairly inexpensive compared to glass fuses and fuse holders.
>> Could do auto blade fuses too.
>>
>> Not sure I have the room for anything but a polyfuse though.
>>
>> Anyone have strong opinions about this?
>>
>>
>>
>
>
>

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