Guess I'm not done yet. Lightning strike DTHC problem.

[Deezl Smoke]

So after getting the torch to fire, the plasma head to adjust according to code, several dry runs, I thought I'm ready to go. Last night I set out to run a bunch of square holes in channel for a customer.

The torch adjusts perimeters, then touches plate, sets to pierce, pierces plate and starts to run, then torch raises about an inch. Tried a few holes to watch the dthc lights and volts/amps etc. Nothing suspect really. But then after only 4 hole attempts, I home the axis and it is over 3" off zero. I had zeroed it prior to starting the first hole.

I put the torch height in manual and was able to cut several holes just fine, but as this is hot roll channel, and 10' long, there is quite a tolerance in height off of the table.
Here's a pic of the mess.

20231005_191329_resized.jpg

[weldguy]

What brand of table are you operating?

Clearly your DTHC is causing your torch to rise during the cut, I would do some straight line test cuts on scrap material of similar or same thickness and play with your DTHC setpoint voltage. You may find simply lowering your setpoint voltage will lower your cutting height to the proper distance.

It is possible your DTHC electronics were damaged during the lightning strike and not functioning properly but these straight line test cuts will give you some insight into that.

If you do the test cuts let us know if you were able to get to and maintain correct cutting height.

[Deezl Smoke]

This is an Arclight Arcmax 6x12'. 2019 year model. Hypertherm powermax 105 head.

Would'nt the DTHC show a fault light somewhere or show a variation in voltage in the program?

[weldguy]

I doubt there is a fault light for the DTHC to indicate it's not functioning properly.

There will be a huge variation in arc voltage from the time you pierce to the time the cut has completed cutting high in the air. If you are not seeing this voltage increase on screen then you are likely not looking at live arc voltage, you may just be looking at your setpoint voltage. Either that or the DTHC is damaged and that's why your not seeing the voltage change on screen.

I would do the straight line test cuts and determine if you are able to get the torch to stay low and stabilize by reducing setpoint voltage 5-10 volts at a time. If it just keeps going up no matter what you do then your DTHC is not reading arc voltage and likely damaged. If thats the case the next step would be to measure the arc voltage coming into your DTHC to confirm you are getting a voltage signal. If you are getting voltage from the 105 to the DTHC when the torch is cutting then your DTHC is damaged.

[Deezl Smoke]

Where would I find the live real time voltage? On the Hypertherm screen, or the program screen?
Going to try the straight line test either this evening, or tomorrow.

[SRdesign]

The torch voltage will be on your computer screen. Your dthc is off for a specified time at the beginning of your cut, then it activates. Weld guy is most likely correct that that’s what is happening. Your torch volts will be green like the attached picture. It is possible that the cpc board in your plasma cutter is bad, and sending a faulty voltage signal to your dthc. As weldguy said, the straight line test will help identify this issue.

IMG_2211.jpeg

[tcaudle]

When torches rise with he DTHC enabled, it says the voltage it SEES (TORCH VOLTS - GREEN NUMBERS) is LOWER than you preset volts.
Most often a LOT less (like zero) .

The only "Fault' it shows would be a voltage fault. There is a Min and Max fault voltage settings and below 50 or about 200 typically will trip a fault. I is not set to STOP motion just to warn. If you cut with a fault on you are guaranteed poor results.


DTHC works like a cruise control . The TORCH VOLTS is the ACTUAL reading of MPH (arc volts) and the preset is what you have set your target Speed to be. The DTHC moves the torch up (to increase) or DOWN (to decrease) the ACTUAL VOLTS. Now, if the Voltage coming back from the torch is wrong, the height will be too.

Other things effect the voltage besides JUST the height of the torch above the metal (Arc Gap). Sometimes a little and sometimes a LOT.

ALSO: If you are losing potion on Z by a lot you are losing steps on Z . The DTHC keeps sending move steps based on voltage and if if a step does not actually move it its recorded but the actual height is off. Like losing traction on wet pavement. Your speedometer shows the wheels moving but the vesical does not. So the solution is to tame the motion down so it does not lose steps. You have two places to do that: The Z axis tuning that controls how it moves in torch lifts and moves between cuts , and the DTHC tuning that controls ow Z mover DURING a cut. Setting the Max velocity or the acceleration to high for your mechanics will cause lost steps. Of course slipping mechanicals (pulleys, belts, couplings ,etc) can have the same effect.

The two problems are separate. On eis a voltage /DTHC problem , the other is a Z losing steps problme