Adcom 555 amp fuse help needed

[hellotheworld]

I found one of the 4 fuses in the box was burned. I figured out that it was 6A 125V rated. But I do not konw if it is a fast acting or slow acting type. Could any one help me? Another question is can I use 6A 250V rated fuse instead? I could not find a 125V one at RadioShack. Thanks!

 

[mpmarino]

I am pretty sure they are fast acting. You should be just fine with the 6a 250v fuse. I run my 555's with 5a on the 4 fuses for a little extra protection.(I'm not talking about the single main supply fuse) They don't pop unless I really beat on it.

 

[anatech]

Hi hellotheworld,
The voltage rating on a fuse indicates what the blocking rating is. In other words, the fuse is guaranted to interrupt a circuit up to that voltage. It will only see that voltage after it opens. Therefore, a 32V fuse is not suitable for supplies over 32V . Your 250V fuse in a 120V circuit is fine.
-Chris

 

[hellotheworld]

I got the confirmation from Adcom customer service that the fuse is slow acting type and I can use 250V rating. As my understanding, we still can use fast acting type as long as do not push it too hard.

Thanks for your helps...

 

[AndrewT]

you should be able to find the rating stamped into the side of the fuse ends. F6A 250v indicates fast acting 6amp maximum running current, maximum 250 volts. T6A is time delay or slow blow and the standard speed is between these simply noted as 6A. By the way all fuses fatigue and may eventually blow after many years use even when operating normally. The lower the operating current then the longer the life. Foe a fuse to blow in its safety mode then the current must be above the rated value. A few tens of percent above rating will blow after some minutes. At 2 to 3 times rating it will blow in a few seconds and many times rating will blow in fractions of a second. The time versus overload curve determines whether it is fast, normal or slow.