40V Max at Torch?

[Eric - Plasma]

Hello all. First of all I would like to thank everyone for contributing to this great site. Being new to plasma, I have been reading all the valuable information learning all that I can!

I have built a 4'x4' table with CandCNC BladeRunner Dragon Cut 620-4 EtherCut + DTHCIV + Feather Touch Ohmic sensor.
For a plasma I purchased a used (looked to be in great condition) Hypertherm Powermax 1000 G3 with hand torch.
I've finally come top the point in my build where I can start test cutting but I have run into a problem with volts at torch reading in Mach3.
So far with DTHCIV off I have cut (not nicely) 11g and 16ga mild steel with 60amp and 40 amp nozzles using the manuals cut recommendations. Torch voltage maxes out at 38V-40V. I have made many changes to feed rate, amps, cut height and there is no effect on the 40V number. Consumables are new.

I suspected the voltage divider card since I measured the input voltage to it while running and it read 135V on a cut that the manual said should be 134V.
With the help of CandCNC it was determined that the card was functioning properly and was told the issue must be with the Hypertherm no outputting a DC current.

I have e-mailed Hypertherm's support but there has been no response yet.

I am at a loss where to go from here. If I could afford it I would just purchase a new machine and be done with it. Any ideas would be greatly appreciated.

Link to one of my build threads.
http://www.pirate4x4.com/forum/shop-too ... build.html

[tcaudle]

Take the raw volts direclty off the workclamp and electode connects instead of J15 and J16 to the RAV card

[Eric - Plasma]

Thanks for the reply. No days off eh.

So I switched the raw volts to directly off the workclamp and electrode connection points.
I now get zero volts coming from the card.
Reading of digital volt meter from leads into card 146V.

[sphurley]

How long and what type cable do you have on the arc voltage points to the divider card and from the divider to the THC sensor card?
I saw your photos and you really don't want that cable very long. You also need to keep things (like the torch cable) away from signal cables.

[jimcolt]

Bottom line: If the Plasma is cutting metal then the Raw output voltage from the plasma is there. The lowest voltage that you could maintain a cut with is in the range of about 65 volts....most cutting at higher amperage and with anything larger than Finecut consumables will be over 100 volts DC.

Jim Colt Hypertherm

[Eric - Plasma]

How long and what type cable do you have on the arc voltage points to the divider card and from the divider to the THC sensor card?
I saw your photos and you really don't want that cable very long. You also need to keep things (like the torch cable) away from signal cables.

The wires from the arc voltage points to the divider card are 18ga unshielded. I crimped, soldered then shrink wrapped the connectors.
23" connected directly to the workclamp and electrode connection points. = 0v
17" connected to J16 + J15 + 40V
The Change here has me baffled? Maybe I am getting some interference?

Divider to the THC sensor card I used the supplied 36" shielded mini jack cable.

The 25' Cat5 from the PWM Module to DTHCIV Module is still quite long. I did try and swap it out for a 6' Cat5 that I had but it made not difference.

I still need to clean up my wiring and sorted some runs but I was waiting until things work working. The DTHCIV wireing isn't very close to the torch cable, except where it's connected to it. The tables frame and electronics cabinet are grounded as well. Although the back of the cabinet is not mounted yet.

[Eric - Plasma]

Thanks for chiming in Jim. The plasma is cutting but not well. Using the recommended settings the cuts barley make it though the steel. I have to slow it down to get it though. Double checked my motors steps per unit of travel and they are set correctly. Also Checked torch tip at cut height and it was correct as well...until the metal warps. Which I did cut a really warped piece and found it interesting that the dross did not change.

Actually I made many changes to the cutting speeds while testing some 16ga steel with new 40amp consumables (25amp machine setting) and it didn't seem to make much difference to the parts bottom dross at all. Every time it was quite heavy which as I understand it means that I am traveling to slow. BUT if I speed it up I do not get good break though of the kirf width.

[Eric - Plasma]

I've read that water in the air can cause the penetration issue that I have. I'm going to pick up a dissicant air drier and give it a try. At least I will have a visual indication when the beads are used up.

Just to rule them out I'll check the resistance of the Powermax 1000 leads as well.

There is an arc...so this low/no voltage reading issue is caused by?

[jimcolt]

Unlikely that water is causing cut quality problems. Start at "ground zero".

-Place a piece of steel of your choice on the cutting bed.
-Using the mechanized cut charts in your Powermax1000 operators manual.....install the appropriate consumables in the torch. Make sure the part numbers all match the part numbers at the top of the cut charts.
- Shut the height control off. We are going to do a test cut at a fixed height. Set the torch cut height with feeler gauges to the book spec of .06".
- Ensure incoming pressure at the rear panel of the Powermax is between 90 and 120 psi with air flowing at the torch.....a gauge must be installed withing 12" of the inlet to verify this. Air will flow at the torch when amperage knob is fully CCW.
-Ensure cut pressure is set correctly by verifying with front panel LED's while air is flowing at the torch.
- Draw a part such as a rectangle with at least 6" length. This will allow the torch to get to full speed.
- Set the cut speed at the optimum (not fastest) speed in the cut chart.
-Jog the torch around and verify the .060" cut height stays constant.
- Set the amperage to the setting in the cut charts for that material /consumables.
- Do a cut, observe the dross if any. If there is dross increase cut speed by about 10%....observe dross.
- Eventually you will find a speed that eliminates dross. If you still have dross in corners or on short sections of the cut...that indicates slow speed....perhaps your acceleration rates are not high enough.


Dross is caused by:

- Cutting too slow
-Cutting too high
-Cutting with a combination of the above.
-Cutting with worn or incorrect consumables.

Jim Colt Hypertherm

[Eric - Plasma]

Thanks for your tips Jim. I have already attempted this by cutting 8" lines on the weekend but will try again. I didn't document very well so this time I'll keep notes and and document the results for each cut.

I did pick up an air dryer today anyway. It is the type with the colour changing desiccant. At least I will be able to see when water is making it though my initial air dryer.

So in your option this voltage reading issue is not caused by the plasma cutter, it is a CandCNC DTHCIV issue? I tend to think it is still a card issue some how but they tell me it's fine and you tell me the Powermax is okay. So I'm at a loss there.

[tcaudle]

The wires from the arc voltage points to the divider card are 18ga unshielded. I crimped, soldered then shrink wrapped the connectors.
23" connected directly to the workclamp and electrode connection points. = 0v
17" connected to J16 + J15 + 40V
The Change here has me baffled? Maybe I am getting some interference?

Interference? On a signal that is over one hundred volts and high current? Most likely the polarity is wrong to get 0 volts. Or the voltage is not getting to the RAV card . Why don't you swap the leads...it won't hurt anything because the card is protected agains reverse connection.

Divider to the THC sensor card I used the supplied 36" shielded mini jack cable.

The 25' Cat5 from the PWM Module to DTHCIV Module is still quite long. I did try and swap it out for a 6' Cat5 that I had but it made not difference.

I still need to clean up my wiring and sorted some runs but I was waiting until things work working. The DTHCIV wireing isn't very close to the torch cable, except where it's connected to it. The tables frame and electronics cabinet are grounded as well. Although the back of the cabinet is not mounted yet.

[Eric - Plasma]

As you can tell I know next to nothing about electrical interference. One of the reasons that I purchased your system instead of attempting to build my own.

I was quite careful not to get the polarity wrong when wiring it directly to the leads. Also checked it with my volt meter and polarity was correct. There was power into the card. Reading was +146V. during a cut.

I'll try and swap them around just to see what happens.

[jimcolt]

The plasma torch will not fire.....and even if it did it could not maintain an arc at 40 volts. You say it is cutting....so I'm sure your actual voltage is above 40. In an earlier post you said you measured the "input volts" to the RAV (voltage divider card) and it was 135 volts. That is normal plasma cutting voltage when cutting thicker material....and that is what you should be reading on your digital readout.

The voltage divider takes the raw voltage, filters its somewhat and divides it to a safer, usable level for the height control electronics. Tom Caudle can explain more about how his circuitry works, however I would suggest that either something is connected incorrectly or there is some sort of issue with components between the Raw voltage input and the torch height control electronics.

If you do my suggested testing...you will see the cut capability of the plasma. With the height control off and the torch set at the correct cut height....you are eliminating all of the height control system and manually cutting. This will take your mind off trying to find whether the issue is in the Plasma Cutter or in the CandCNC components. It is always good to eliminate the possibility of issues in one system vs another when troubleshooting.

Jim Colt Hypertherm

[Eric - Plasma]

Thank you for your help Jim. I've made up a spread sheet to document changes while I tackle the dross issue this weekend. If the Hypertherm in indeed working correctly I am confident the dross can be sorted out.

[Eric - Plasma]

Why don't you swap the leads...it won't hurt anything because the card is protected against reverse connection.

Okay swapped the leads that were connected directly directly off the workclamp and electrode connects. Voltage reading went from 0V to the 37V-40V.
So look like I had those wires backwards but I'm still not getting the proper Voltage reading.

[sphurley]

Have you measured the voltage on the shielded cable before it plugs into the PWM?
You do have the dip switches on the PWM set for 7:1? (make sure they "click" into position.

[Eric - Plasma]

Checked Voltage from the stereo jack coming from the RAV-01 Raw Arc Voltage Divider Card that is installed in the Hypertherm Powermax 1000 and it read 4.35V. Should have been closer to 18.5V

Raw Arc Voltage Divider Cards jumper is set to 1-7 .

[sphurley]

Do you have a RAV01 or Rav02?
The 7:1 switches are on the bottom of the PWM, those are the ones you checked?

[Eric - Plasma]

Rav01.

My PWM has a jumper on the bottom that you move for the different ratio's. I did not move it since it came set to 7:1.

[sphurley]

OK, Put your hand torch on, disconnect the ARC OK, and torch switch wires from the RAV along with the PWM cable. Manually cut something and measure the output of the RAV card. Lets see if something is pulling the output down.

[Eric - Plasma]

I'll give that a try in the morning and report back. Thanks.

[Eric - Plasma]

So I unpluged the connector for arc ok and torch fire from the PWM. Fired the hand torch with it's switch and the VOLTAGE WORKS!

So next I tried a few things to check what resulted:

Switched The raw volts input to the RAV card back to the Hypertherm J15 +J16 connectors = Works
Connected the PWM back up and removed the input arc ok and torch switch wires into the RAV = Not Working
Reconnect everything then removed arc Ok wires from PWM side = Works
Jumpered arc Ok at PWM = Works
Jumpered arc Ok at RAV input = Not working
Ran new arc Ok wires from RAV to PWM = Not Working
Back to original then removed just arc ok wires into RAV = Broken
Back to original then removed just torch switch wires into RAV = Broken

So I thought the arc ok and torch switch signals were separate from the Voltage divider in the RAV card but seems they are not.

Finally getting somewhere thanks sphutley!

[sphurley]

I have to look over the wiring on paper, my head hurts otherwise. You need to keep in mind that the voltage out of the divider is VERY current limited.
Any slight drain on that will pull the voltage down as you are seeing.
Give me a few to think it over

[sphurley]

Do you have the Arc OK and Torch going to the RAV01 and then the jumper from the RAV to the PWM?
Have you tried running the wiring from the plasma straight to the PWM (this is how it works on my PM65)

[sphurley]

See attached

Pages from DTHCiV-Setup-Config_REV3.1-Page66.pdf

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