Max40 Arc stops

[aefriot]

I know it's an old machine, but I do with what I can.

I can get an arc to start the cut, but the arc stops after maybe half a second. I can immediately start the arc again, but it soon stops after the same half a second. Does it have something to do with a timing or hand-off issue? Air pressure is maintained at or near 60 psi. It does not matter the output power setting. There are no air leaks that I can hear. I'm good with a multi-meter.

In advance...thank you for assistance.

[weldguy]

60psi is very low and could cause what your seeing. The Max40 requires 70-120 psi supplied to the power supply. I would bring 100psi into the machine and give it another go.

[aefriot]

While I haven't used it much, I have cut only about 40 feet with it at 60 psi. Seemed to work at that. The place I bought it from has 60 psi marked on the machine.

The Esab 1125 I run at about 90 psi. But I thought that was just because it was a much more powerful machine.

I'm sure you have much more experience with the plasma machines than I. I will try the pressure starting at a 70 psi minimum and see what happens. Will get back to you tonight.

Thank you.

[robertspark]

https://www.google.com/url?sa=t&source= ... eG7quWXpU8

page 31, set the machine regulator at 60psi

the compressor supply will need to be higher from the compressor.

sorry never used a max40 before

[aefriot]

OK, turned pressure up and no change. After 1/2 second the arc goes out.

I did, however, find that when I turned the air pressure back to 60 psi I could drag the tip with the power turned down to keep an arc. But as soon as the tip leaves clean metal the arc goes out. Also, if the tip hits rust or paint the arc goes out.

Air supply line has always been 120 psi.

[Blackslacks]

Grounding issue? Are you attaching your work lead directly on the material? Check that and you're whole work lead itself all the way back to the machine.

[aefriot]

OK, got the manual downloaded. Thank you, robertspark. Page 4-3:
--------------------------------------------------------------------------------------------
8. Push and hold start switch on the torch to activate the pilot arc

• A two-second gas preflow delay starts timing

• After the two-second preflow, the following occurs simultaneously:
  • The main contactor (2CON) closes, illuminating the DC red light
  • High frequency energizes and times out after one second.
  • The pilot arc circuit activates

9. The pilot arc initiates and transfers to the workpiece if the torch is near (0.15") or touching the workpiece.

If the torch is not close enough to the workpiece, high frequency and pilot arc shuts off after one second and must be restarted and releasing and re-pressing the torch start switch.
--------------------------------------------------------------------------------------------

It appears my machine is operating as designed. After using the Esab 1125 and its greater power, I was holding the torch too far from the workpiece. I was accustom to the distance I could hold the torch head and was holding it further than the 0.15" in the manual. I guess I must drag it to use it.

Still, I think something is amiss. I cannot put my finger on it or into words. Maybe at a later date when I think about it more.

Thank you all.

[weldguy]

I should have been more specific in my reply above. Bring 70-120 into the power supply then set the the machines regulator to 60 psi. Either way gld yuo have it figured out. Thats some old school stuff!

[aefriot]

Yah, I bought it cheap enough because it had some bad fuses. Hmmmm, maybe it blowing the fuses that has something to do with my problem. I replaced the fuses when I got it. It would cut like a champ. Even cut 5/8" brush hog blade even though it is rated for 3/8". Thought the 220V Max40 would come in handy because we live off grid and I wouldn't have to start our bigger generator like I do to run the 460V Esab.

I have had no issue with blowing any fuse.