Triac blowing fuses

[davidimurray]

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]

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]

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

[Denford Admin]

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]

for economy you can try rusty nails as well

[bradders]

They need to be shiny nails