Triac blowing fuses

davidimurray · Post by **davidimurray** » Thu 09 Aug , 2007 8:38 am

Hmmm - our Triac at work has started blowing fuses - I say blowing but vapourising would be a better description! The machine powers up ok, but as soon as you turn the drives on the fuse goes

Time to get the meter out.

Roy · Post by **Roy** » Thu 09 Aug , 2007 21:41 pm

Hi David,

I had similar problem a while back. Powered up ok, but switch the drives on and bang!. I went through a whole pack of 5 amp fuses. Then tried a 10 year old? fuse from an old plug and hey presto. Couldn't work this one out but someone told me modern fuses blow right on or below the ampage limit (for safety reasons?). Where as the old ones had a bit more 'give' in them. So I would guess that when you are switching the drives on you are pulling the full 5 amps or close to.

Give an older fuse a try, or if your brave stick a 13 in !, But i didn't tell you to do that!

Roy

clarkea1 · Post by **clarkea1** » Tue 14 Aug , 2007 11:09 am

Mystery solved!

One of our electrical guys at work took a look and pointed out that we should be using ceramic fuses not glass ones as we were. Apparently ceramic fuses can take much higher inrush currents at start up (i.e. when we powered up the drives). So, the moral of the story is - if your fuses blow, check if they're ceramic!

On the down side, we don't now get to convert the machine to Mach3

Alastair

Post by **Denford Admin** » Wed 15 Aug , 2007 9:47 am

You can also try to specify slow blow fuses as well - they can also be glass, but you will see that the fuse wire looks like a little spring:

Triac whizz · Post by **Triac whizz** » Wed 15 Aug , 2007 16:08 pm

for economy you can try rusty nails as well

bradders · Post by **bradders** » Wed 15 Aug , 2007 16:11 pm

They need to be shiny nails

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