Volts at Torch

[hsolve]

Good morning to all
I have had lately on alli a problem with the torch crashing whilst cutting. I have left post regarding this on the Candcnc forum without an answer that I can understand. My problem is using the cut data from the Hypertherm book (I have PM125) of 126 volts gives an excellent cut but only briefly till the torch drives into the job. Finally I raised the torch volts to 140 and no further problems. The top edges have now become slightly 'fury' which they were not at 126v. The DTHC IV is however maintaining the torch volts within 1v of the set volts.
Hoping to get some feed back from Jim Colt on this issue if possible.

[muzza]

Probably more important than what the set volt set point is, what is the cut height? If it's furry it's probably a little too high. If so slowly reduce the set volts until you have book spec clearance.
Murray

[jimcolt]

The voltage settings that are in the operators manual for Hypertherm systems are correct under the following conditions:

- Cutting at book speed setting. Slower will cause the torch to run closer to the material.
- Consumables are new. Worn electrode or nozzle will cause the torch to run closer to the material.
- Incorrect torch cut air pressure.
-incorrect consumables (verify with the cut chart part numbers)
-Calibration issues with your height control output
-Incorrect settings on the voltage divider output (if used....perhaps wrong ratio for your height control?)

What is important for cut quality is that the physical cut height listed in the cut charts is maintained. Do a test cut on the material you are cutting with the height control in manual, with the torch at the specified height, observe the feedback voltage on your height control. Use that voltage for cutting .....it is ok if it is higher or lower than the book specification for voltage as long as the physical cut height is correct.

Jim Colt Hypertherm

[tcaudle]

Each volt of Preset represents about .01 inch of ARC GAP. An important test is to make a Manual Cut (DTHC in MANUAL and OFF with it cutting at the correct arc gap (standoff) and see what the TORCH VOLTS really are. That then gives you a target to run your preset. If you find that the voltage is higher than your Chart calls for then you should run the built in Volts Test in the PWM module. On the larger plasma units (105 and up) there have been circumstances where the internal voltage divider is getting feedback from external signals. Make sure that you do not have the ground calmp lead coiled up under or near the plasma cutter. Make sure your table is well grounded .

The important thing is that you cut at the right Arc Gap as defined in the Hyperthemr cut chart. Torch Volts is a function of the arc gap. You cannot "set" the volts. The Preset Volts is the value that gives the right height.

Bottom line is the numbers in the charts are good guildlines but are not cast in stone. The Toolsets are editable for that reason.

[hsolve]

Thankyou gentelmen for those answers.
I will look into this further when time permits, for now till the job is finished will stay with the current settings. I will notify the results in a later post when completed.
Thanks again!

[hsolve]

Good morning to all
Just completed the job of cutting the alli parts. I converted the imperial cut data setting to metric and entered them into the tools. On the 6mm alli plate just set the volts just 5 volts higher to be safe and no problems. The 20mm alli plate straight conversion from the imperial cut data to metric and all cut well. Did however have a problem with sheetcam, which came up with a fault, but resolved once I noticed that there was a backup and used the backup. Overall the whole day was spent to get four items out but finally that was achieved.
Thanks to all!

[BensPlasmaAu]

Hsolve,

Did you get my PM reply. It's seems to be still sitting in the outbox. Tried to send it again but not working??? I'm doing everything on the mobile at the moment so things are not working properly.