Society of Robots - Robot Forum

Electronics => Electronics => Topic started by: Admin on July 07, 2008, 12:35:14 PM

Title: used resettable fuse before?
Post by: Admin on July 07, 2008, 12:35:14 PM
I'm considering using a resettable fuse for my fish bot.

The major advantage is that I won't have to remove waterproofing seals if a fuse blows (just trust me on this).

The disadvantage is that the waterproofing thermally insulates it, possibly causing it to build up heat and trip early . . .

Anyway, the question is, has anyone used a resettable fuse and have opinions on it?


And as a side note, I found this nice reference for resettable fuses:
http://www.circuitprotection.com/04Databook/A_fundam_(15-42).pdf


edit: on second thought, since its underwater, I probably won't use this fuse type . . . my waterproofing is flexible so pressure will get applied to the fuse . . . and I'm too lazy to make/test a prototype to check . . .
Quote
Pressure on the device will affect the electrical performance of the device. If the pressure is sufficient to restrict the expansion of the device during a trip event then the device will fail to function as specified and could result in device and equipment damage. Care should be taken to avoid mounting the device in such a way as to constrain expansion.
Title: Re: used resettable fuse before?
Post by: Commanderbob on July 08, 2008, 09:53:38 AM
How deep is the fish bot going to go? I doubt it will effect the fuse very much. It will probably just take a little more current to make it trip.
Justin
Title: Re: used resettable fuse before?
Post by: Admin on July 08, 2008, 10:00:53 AM
Not sure . . . 6 feet sounds like a good number . . .

There really isn't any way to know if it will work or not without trying it, too many variables . . . I'm on a deadline so its a bit risky . . .

For now, I've decided to just go with a SMD fuse and hope for the best.

but I might revisit this idea in the future . . .
Title: Re: used resettable fuse before?
Post by: szhang on July 08, 2008, 01:48:00 PM
could you have something like this?
--------------
|-----------
[][fuse]
|--^----^---

and bury it in the body of the fish where [] is a rubber plug of some sort, ^ are the metal contact

this way if the fuse blows you just remove the plug, pull out the fuse, and pop in a new one.
Title: Re: used resettable fuse before?
Post by: Commanderbob on July 08, 2008, 08:47:06 PM
For only 6 feet I think it would work fine. I don't know though and as you said the only way to know is to try it. I know the temperature affects them quite a bit so underwater could be colder making it take more current to trip. If I had one I could try it in my 8 foot deep pool. ;)
Justin