But the SyncInjector has overcurrent for each radio and the SyncPipe. So
I'm not real worried about things cooking with that. Exactly as you said
though, with no protection, a single radio, SS, whatever shorting takes
the whole site down. And that's ungood. I've had to replace a bunch of
relays on the SiteMonitor controlled PoE injectors because, well, I was
stupid. And I don't want to do that anymore.
On 8/19/2015 12:51 PM, Ken Hohhof wrote:
What got me on this track was discovering the replacement fuse for the
Trango ApexPlus/Lynx/Stratalink POE boxes is a 3.5 amp medium blow.
It’s kind of amusing because the single radio power supply they sell
is only rated 1.5 amps, so it can’t blow the fuse. But when I power
it from a 6 amp Mean Well, the fuse glows like a little incandescent
bulb for a fraction of a second before opening.
So I was just wondering if the medium blow fuses had their place.
Some distributors like Allied don’t even have them in their catalog,
so I guess they are a rare bird.
I also learned from perusing the spec sheets that fast blow fuses
actually take 30-60 minutes to blow until you get over 200% of rating,
at 300% it comes down to milliseconds. That probably explains George’s
experience with 1/2A fuses. But also with a 5A fuse on a Syncinjector,
if the power supply can’t put out at least 240 watts, things are going
to cook for awhile before that fuse blows.
*From:* Forrest Christian (List Account) <mailto:[email protected]>
*Sent:* Wednesday, August 19, 2015 12:16 PM
*To:* af <mailto:[email protected]>
*Subject:* Re: [AFMUG] medium blow fuses
A fast blow fuse is really very very slow when compared to
electronics. I'd recommend sticking with the fast blow fuses. If
you're asking because you have nuisance blows I might consider just
moving up a amp or so depending on what you're protecting.
On Aug 19, 2015 6:47 AM, "Ken Hohhof" <[email protected]
<mailto:[email protected]>> wrote:
I use fast blow 5x20 mm fuses for radios and other electronics,
but recently became aware that medium blow fuses exist. Not
widely available, but examples are Belfuse 530-5MT and Littelfuse
233 series.
So is anyone using these? Any advantage? I'm thinking devices
that might have enough inrush current to blow a fast blow fuse,
although that hasn't been a problem so far.
