Arc OK intermitent issues on torch fire

phillc54 wrote:

Lots of variable in play, humidity etc.

Is that previous schematic how you are currently connected.

That is my exact wiring right now. (also in Victoria so pretty stable )

phillc54 wrote:

It is looking more and more like an issue in the machine then.

Do they use a mechanical relay?

From what i got back from them yes its a dry contact mechanical relay.

phillc54 wrote:

OK, if not I was going to suggest swapping 12 and 14 to reverse the current direction in the machine.

Seeing as you have checked all the wiring and connectors, I have run out of ideas...

might try that anyway cant trust what they say half the time. If not i might do a dodgy and pick up a new machine from a tool shop hook it up and see if i am having the same issue or not, then return the machine.. lol
Then just send mine off for repair or whatever they want to do.

tommylight wrote:

Again, lower the pierce height.
Try 3 or 2.5mm, see if that happens again.
If the torch is high it can not reach the threshold to activate the arcok signal, although the arc is established and cutting.
Or raise the cutting current a bit if possible.

Ill try that.

tommylight wrote:

Again, lower the pierce height.
Try 3 or 2.5mm, see if that happens again.
If the torch is high it can not reach the threshold to activate the arcok signal, although the arc is established and cutting.
Or raise the cutting current a bit if possible.

Yer still having the same problem unfortunately

phillc54 wrote:

That will give you around 24mA which would "probably" be adequate.

24 mA is well below the min current rating of most internal Arcok relays of 100 mA (certainly hypertherm, Everlast and Thermal Dynamics).

You need to add a pulldown resistor of around 90Ω 10W assuming a 24 volt ArcOK circuit and a Mesa card. Connect it from the Mesa input to -24 volt.

To achieve this from readily available parts we recommend to:

Get 3 x 270Ω 5W Resistors (Jaycar PN RR3284) and wire them in parallel. This will give 90Ω with 267mA and 6.4W of dissipation. 3 x 5W resistors in parallel will give you 15W power dissipation capability, so plenty of margin. Leave an air gap between the resistors though.

Expect to have to cycle the ArcOK a few times to burn off oxidisation. The last time this came up the user said
"After all this, and Rod's new arc ok resistor resistor blowing away the built up oxide, I am getting reliable cuts with about 30 minutes of cut time not throwing up a single error yet."

I'll leave it to you to find the thread.