cnc plasma cutter problems
hi i have a 3 axis ebay controller and the problem i have is iam using the spindle relay to turn the gun on/off, ive tapped into the two wires off the plasma gun but when the relay fires the gun the control board trips a limit for the e/stop. even if i disable the e/stop in the input setting its still doing it. and ive even tryed running a extra relay but it still trips the control board. the relay runs a 12v bulb ok wired to a power supply so i no the relay is working ok. i think its down to the feedback off the gun.
anyone no if it is the feed back off the gun or got any ideas how i can stop the feedback off the gun.
thanks adam
Re: cnc plasma cutter problems
Just a thought have you put a diode on the relay to stop spikes when the relay operates.
Peter
Re: cnc plasma cutter problems
Quote:
Originally Posted by
ptjw7uk
Just a thought have you put a diode on the relay to stop spikes when the relay operates.
Peter
not tryed it yet but i will have a go later and see if it works and report back.
i was looking into using a solenoid to press a micro switch so there isnt any contact with the controller and plasma gun. but if the diode works it will save me a lot of messing about
thanks
Re: cnc plasma cutter problems
The diode would depend on the relay voltage etc, a standard silicon 400v at 1amp should do
Peter
just remember to get it right way round else you could blow it!
Re: cnc plasma cutter problems
Quote:
Originally Posted by
ptjw7uk
The diode would depend on the relay voltage etc, a standard silicon 400v at 1amp should do
Peter
just remember to get it right way round else you could blow it!
thanks for your help but i think i jumped in to fast lol. i disconnected everything the plasma cutter was on the other side of my shed and it still put the e/stop on on the controller and my computer went mad. so i think its just the hf off the plasma cutter going back thought the plug to the computer. there in the same socket as i only have 2 plugs in my shed on the same ring. iam going to try and run a cable from the other ring main in the house and see if it still happens. iam so close to getting this running now its doing my head in pmsl.
adam
Re: cnc plasma cutter problems
If you are having problems when the plasma unit starts then this will be the HF signal. HF gets everywhere. I have seen it do many weird things to computers and controllers. If your supply cable to your shed is something like a twin and earth or a small armour cable its probable that the earth cbale simply isnt big enough to cope with the HF noise. You also need to ensure that your plasma unit workpiece cable is securely attached to your cutting table and the plasma unit. If the HF noise problem is still an issue you might need to look at turning your shed electrical installation into a TT system. This involves removing the electrical earth from your shed supply and installing a copper earthing rod system outside your shed and connecting this to your shed electrical distribution board. I would recommend getting a qualified electrician to carry this out if you decide to go that way.
Regards
Ian
Re: cnc plasma cutter problems
£400 seems to be a bit steep for a couple of rods and some earth cable and crimps. But then again it will have to be tested to ensure it is ok and someone will be supplying a certificate with their name on it saying that it is fit for purpose. If you are going to run in a new supply to your shed you first need to work out the amount of current you will need, then the length of cable run. From this the cable size can be calculated. If you need help with this post the figures and I will work out the cable size for you.
Regards
Ian
