Messages

1

Show"N"Tell ( Your Machines) / Re: China HF-start plasma CNC design!

« on: April 03, 2013, 04:27:34 PM »

Worked with table mfgr, think we've got it figured out !

I'll post in the forum (don't wanna hijack your thread) with results.  Thanks again for your help sir..

2

Show"N"Tell ( Your Machines) / Re: China HF-start plasma CNC design!

« on: April 03, 2013, 01:58:11 PM »

Yes.

Perfect.  Confirmed this with plasma table mfgr as well.

No. Current transformer is for measuring current. It won't work with plasmacutter because the current is practically DC. You
would need a current transducer for DC (hall-sensor based, for example), and this signal could be used for producing an "arc ok"
signal.

For measuring the voltage (which is also practically DC) you only use a resistive voltage divider with some additional components to
shield your electronics from high voltage (of HF start) and noise.. If you are not familiar with electronics, I wouldn't try to build
it but get a ready made THC which has the divider etc. in it..

I think CandCNC makes a "retro fit" kit for older cutters and those without divided voltage or arc ok signals.  At 132 bucks, this should get me the signals I need for the controller.

Cheers !

3

Show"N"Tell ( Your Machines) / Re: China HF-start plasma CNC design!

« on: April 02, 2013, 06:17:54 PM »

The wires going to the torch switch need to be connected to a PC controlled relay
that connects the wires together for starting arc. Just like pressing the switch on
the torch.

Arc ok needs some current transducer to measure the DC current to arc and a limit to set the signal
after reaching high enough current. I have not implemented it. I just wait a second after switching
on the arc.


Also I have not implemented arc voltage measurement.

Sooo...for the plasma on, I believe this is the relay board inside my controller.  So, hooking up the plasma torch wires to it should do the trick !?!?

http://probotix.com/relay_boards/rbx-1_isolated_3_channel_relay_board/


As for the arc voltage, It's looking like I'm going to have to get a current transformer and divide the voltage from that to get the 20:1 required input for thc.

4

Show"N"Tell ( Your Machines) / Re: China HF-start plasma CNC design!

« on: April 01, 2013, 10:58:22 PM »

To be honest, I wanted to get more cutting depth and recently bought a new plasma with 25mm cutting capability. For this, I found Everlast powerplasma 60, which is a pilot-arc plasma and has 3-phase input so I don't need large fuses. Plasma cutter works fine, Everlast is a funny company though. Had lots of trouble finding who really sells the plasma cutter (official importer just said they'll have more in future, maybe next month, maybe later), and after buying the plasma cutter (from another company that apparently had bought it from official importer as it had their sticker) they didn't give me access to their official forum but banned me from the forum - just for registering. Really strange. However, the plasma works fine, and was really reasonable price. I'm using a modified WSD-60P torch.

As long as I used the "tuned" chinese HF start plasma, the consumable lifetime was about the same as using it with manual torch. Not that good but the consumables are cheap.

I have been happy with performance without height control so I have not implemented it.



What do you mean, how to wire the cutter? Power in, plasma on/off with relay (to torch "start switch" wires).

Ok....sorry to keep asking questions.  But plasma gets hooked up this weekend want to get it cutting ASAP.
Soooooo...my controller needs two wires for "plasma on"...these are the switch wires, correct ?

I also need wires for "arc ok" and arc voltage.  The voltage I assume will have to come from the torch leads in the form of "raw voltage", then divided.  What about the "arc ok" signal wires ?  Any thoughts ?

Thanks again in advance....

5

Show"N"Tell ( Your Machines) / Re: China HF-start plasma CNC design!

« on: February 20, 2013, 01:20:27 PM »

I would also ask,

Do you have any info on how you wired up the cutter ?  I've been working for days to get some info with no success...

6

Show"N"Tell ( Your Machines) / Re: China HF-start plasma CNC design!

« on: February 20, 2013, 09:42:41 AM »

My next questions would be....

How's it holding up ?
Are you using AVHC ?
How long do your tips last ? (piercings ?)


Thanks again for the reply's....helps alot ! 

7

Show"N"Tell ( Your Machines) / Re: China HF-start plasma CNC design!

« on: February 19, 2013, 10:05:22 PM »

Just purchased a burntables unit, should be here in a few weeks.  I've also purchased a machine torch for my simadre cheap chinese "Cut50" unit.  I'm going to try and use it to get buy until I can get my hands on a larger hypertherm unit.  With that said....you talked about grounding the torch head.  I can see where you have the alligator clip...but where does it go to to get grounded ?  Do you have it specifically to the grounding rods or just to the ground on the plasma cutter.  Any help is appreciated.