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GB: Round #2; Fo-Felix EMI Filter for AC mains 120/230v; By Folsom

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So i just realized that after i looked carefully at the PCB.
The Fuse is necessary for the Comoco and is bypassed for the other bigger cmc.
I dont know why omitted the fuse on purpose !!
Sorry for this stupid basic error, should now better.
I hope this serves to alert others ....
Sorry for this again...
 
The resistor pops (if it hasn't already) and no current flows.

So given that the resistor will explode in the case of the fuse opening due to a fault down circuit, should this fuse not be relied upon for circuit protection? Is it expected that users will include an additional fuse between the Folsom and the mains?

A clear schematic would help to clarify this, the one at http://www.diyaudio.com/forums/grou...r-ac-mains-120-230v-folsom-2.html#post5401372 shows the fuse in series before this resistor. Is that not the case? It sounds like the fuse paralleled.
 
The fuse isn't for circuit protection. It is for Comoco protection. If the Comoco sees too much current it'll melt the insulation off of it. They're expensive and hard to replace compared to a resistor.

Your amps and such should have their own fuse, and you can implement a fuse or circuit breaker into a distribution box as well if you built a power conditioner.

If I launch a GB #4 I think I'll make it so the resistor has two holes for mounting, one fused, one not. You're right to noticed the schematic is slightly different. The reason is because you'd need a fuse for 1 single resistor when running the Bourne inductor, and that would be silly. I wanted to keep it simple, but now I can see that it is simpler to choose another hole than resolder a resistor.

You could mount the resistor to the fuse connector on the input side if using a Comoco. Underneath would be an easy way to do it, so you won't ever blow the resistor. This is an easy choice if you're worried about replacing a resistor. I'll include a pic of this shortly.
 
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Is it like a transformer snubber, except since it's a CMC, it ends up being a bypass instead of across the line? I found diyaudio threads about determining transformer snubber values through measurements (requiring a jig, generating a square wave, reading a scope), which sounds like a lot of trouble to setup except you avoid math and get real world optimized values.

What is the (your) process for determining the CMC bypass? Do you begin by modeling the reactivity of the chosen CMC...?
 
Here is how to wire the bypass resistor so it won't blow if your fuse blows. This is only for use with the Comoco's. The Bourns inductors won't ever need this.


That makes sense. I was going to say that the next revision of the PCB should have this incorporated, that is, the resistor only conducts when there is a Fuse present.
Otherwise, it will happen like what i experienced and get Blown resistors (i did not place the fuse when using Comoco, and as such the resistor feeds an entire 400W amplifier)
 
The nextgen will have an extra hole for the resistor. Making the holes identified is a bit tricky with limited room in the area of the board. It is inconvenient to replace the resistor, but the chokes on the other hand if over driven will get ugly as the enamel melts - the whole reason for the fuse since you don't know until it is way too late.
 
The nextgen will have an extra hole for the resistor. Making the holes identified is a bit tricky with limited room in the area of the board. It is inconvenient to replace the resistor, but the chokes on the other hand if over driven will get ugly as the enamel melts - the whole reason for the fuse since you don't know until it is way too late.


Give a shout out when your about to do a nexgen.
 
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