Fuse blowing up - Electronic Circuits Projects Diagrams Free

MuLdEr · 14th February 2005, 10:47 AM

Hello,

I had a problem, look at the schematic, I built power supply like this, and the problem was the fuse blew up always when I turned switch on. I sorted out this one with placing fuse before switch, but still I don't know what was the reason of fuse blowing up, maybe you know??

**Nigel Goodwin** · 14th February 2005, 11:24 AM

Quote:

Originally Posted by MuLdEr

Hello,

I had a problem, look at the schematic, I built power supply like this, and the problem was the fuse blew up always when I turned switch on. I sorted out this one with placing fuse before switch, but still I don't know why was the reason of fuse blowing up, maybe you know??

You should make sure you use an anti-surge fuse, particularly if using a toroidal transformer - toroids have a much greater switch-on surge than conventional transformers. As the toroids get larger, you need to implement soft-start circuits.

Placing it before, or after, the switch shouldn't make any difference, electrically it's identical.

JimB · 14th February 2005, 11:37 AM

Inrush current at switch on, definitely. Especially with all that capacitance after the rectifier.

You must use a slow-blow or an anti-surge fuse.

JimB

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14th February 2005, 11:37 AM	(permalink)
JimB	Inrush current at switch on, definitely. Especially with all that capacitance after the rectifier. You must use a slow-blow or an anti-surge fuse. JimB