New 2016 250EX inconsistent start and frequency

[ozcheek]

Hello all, Oz Cheek here.
The new 250EX arrived just before Christmas.
I was pleased to see how well everything was packed and protected.
Monday of this week I used the machine for the first time.
After reading the manual and watching several videos on this machine, I felt equipped to try it out.
My previous experience is with a Miller Dialarc 250 HF purchased new in 1987 and a Lincoln Idealarc tig 250
My dad gave me my first machine when I was 14. Airco 225 Stinger, which I coupled a high frequency unit to be able to weld aluminum.

When I cranked up the new machine, I noticed the start frequency was not always present when the pedal is applied. If the arc didn't initiate, throttling up, then down would sometime get things going. It similar to not having a good ground.
When the arc initiates, the frequency pulse seems to increase with pedal travel.
Several different settings have been tried, including frequency balance, starting with 45% and going down to 10 %
Amps from 74, down to 35.
The torch is a Radnor 20 WC, tungsten 1/8 2% Thoriated GTE Sylvania. 100% argon 15 cfm.
Material in this case 60-61 .075

After using a newer inverter welder belonging to a friend, the first thing I noticed was how smooth the arc was compared to my transformer machines. Unmatched control and finesse. As you can imagine, I couldn't wait to purchase a newer generation machine. Over the past two years, I have been researching the market place, reading many of the posts on various forums.
I'm confident that there will be a simple solution for what I'm experiencing.

[christian]

Well,

Your pre and post flow settings could be faking you out, i.e., keep the pedal down till the pre flow is finished or set the pre flow to 0, because if you let up, due to wondering why it's not starting, and then try again, you could be caught waiting for the post flow stage to finish, before an arc can be started. So you could be creating a non-starting loop, so to speak, just due to a matter of timing and settings. And, you can hear the post flow finish if you listen for it, and if your machine fan is quiet enough. I'd set the post flow to only 4 seconds, and skip the pre flow altogether, as you're getting familiar with the machine and its settings.

Peace,
C. Livingstone

[christian]

And,

That may only be the case for the contactless, High Frequency starts. At any time during the post flow stage an arc can be initiated with a scratch start, I believe, at least on my particular machine, if I'm remembering correctly.

[ozcheek]

Thank you Christian. We are on the same page. I turned off the pre flow all together, the post is at 10. The pedal can be applied and held 2o-25 seconds. On a no op pass. Static is sometimes visible, sometimes not. The static will quit if you hold the pedal down. It is when you actuate, and mostly when lifting, that you get ignition. Although then again, sometimes it lights right away.

[Rambozo]

One tip is to touch the tungsten to the work right before starting. I've noticed that some machines will build up a slight charge and it seems to fake out the auto HF start circuit. You might even see a small spark when you do that. Then after touching position the tungsten where you want to start and hit the pedal. See if it starts good, then. I also zero out the preflow for better control. But I usually tap the pedal so the postflow is running while I do the above routine, then I have shielding from the moment I start without any of the lag that comes from using preflow. A lot of this is personal preference and the kind of work you are doing.

[christian]

Yeah,

I don't have a lot of time on my Everlast machine either, but have gotten into the habit that Rambozo mentions, of touching the work with the tungsten and lifting to the ideal gap before starting, which does often seem to discharge a slight bit.

Otherwise, if you're going down to 35 amps with 15 cf of gas flow, especially with a necked-down cup and no gas lens, you'll have tougher arc starts, I'm pretty sure. A #7 cup and less gas flow at the lower amps will probably help.

[ozcheek]

Will report back after trying that. Thank you both...

[rick9345]

My 250ex
1/8 tungsten doesn't start as easy as 1/16
My rhythm is less than .5 sec preflow,tap pedal, touch work piece with tungsten,position torch,initiate with pedal and gradual increase to weld amps.

[christian]

Also,

You might want to kick up the start amps, if your machine has that ability, beyond the machine's actual minimum. Like, if it's has a 5 amp minimum capability, set it to 15 amp starts, which will probably give a snappier or more stable start.

[performance]

OZ,
Have you downloaded and read the manual?
Frequency adjustment has nothing to do with start HF. Nor the balance. Pulse does not either.
Inverters do not use HF while welding in AC, only during the start. What you are adjusting is actually the AC frequency, not the HF frequency.
Your tungsten is really too big for the amp ranges you discussed. It will make arc starting more difficult, especially if you have too large of an air gap between the end of the tungsten and the piece of metal.

For setup for welding aluminum, you need somewhere between 100-150 Hz for most purposes. And you will need no more than 35% balance.
As mentioned, the start frequency can be delayed by having 2T/4T settings out of whack...which sounds like you might have something just a little out of whack since throttling up and down clears it up. But the unit should stop the arc and throw a code eventually if the arc does not stop with the pedal pressed down.

You should try to operate it with the torch switch and see if this is still an issue.

Are you grounding direct to the work and do you have a place ground and cleaned where you are trying to weld.

Are you trying to ball your tungsten?

[christian]

Gee,

I think I gave a little bit of inaccurate info.

My HF arc starts don't need to wait for post flow to finish before initiating another contactless start. I just checked on AC, and it initiates contactless starts in rapid succession. Sorry for suggesting otherwise.

[ozcheek]

Thank you Mark, I provided incorrect info on tungsten, it's 1/16 not 1/8. We were out yesterday and I have not had the opertunity to try these and others good suggestions. To clarify, when the arc does start, the perceived speed of switching, (frequency)is slow at first, then as more heat applied, speeds up. I adjusted the number value up and down to see if I could decern a difference. I thought the once the arc was established, the switching would remain constant ?
The ground clamp is attached to the vise. The work is clamped in the vise. At first, I had the AC balance adjusted at 50% The tungsten balled and receded back into the cup, right away. I then adjusted the setting to 35. Now I'm at approx. 28. Yes, I have been reading the manual online, did not print.
The tungsten is always ground to a point and unless I contaminate it, continue to weld as it forms a ball. The method used is a cordless drill, with the tungsten pointed in the direction of rotation of a 14" disc sander/grinder. The Hz have been above 100 except when I adjusted to 60, just to see the difference. The 2/T 4/T settings have been left off. Am I correct in thinking that unless I switch from remote to those, they do not affect operation?

[performance]

What switching are you talking about? Do you have the balance around 30%?

[christian]

Gee,

I'd skip grounding through the vise for a while, and ground directly to your work piece until you get settled in with your machine.

[ozcheek]

The switching; AC wave, I am trying to be clear, I should have said frequency. Balance 28

[ozcheek]

Will do, thanks

[ozcheek]

Good idea, I'm used to the behavior of the other machines, need to remember,not the same, thanks

[performance]

The sound of the frequency changes with increased amperage by the nature of it. It gets louder and more aggressive. I don't think you can tell merely based on sound. This is happening so fast that sound is only a certain pitch and it will increase in intensity as you go down on the pedal.

[ozcheek]

Good idea, I'm used to the behavior of the other machines, need to remember,not the same, thanks

[ozcheek]

Ok, reduced the LPM to 10, connected ground to work, next size larger cup, verified balance below 30. Frequency 120
Amps 70. All other controls off. Same scenario. One more event, tungsten balls immediately and will recede in a short time as if the balance is cranked up. I'm beginning to believe there is an issue with the machine.