Another HF 90 Amp Flux Core DCEN Conversion

[bob58o]

Hello

And Hello to you good Sir.

 

[bob58o]

Started putting some wires on things.

 

[Hellion]

Hey wait, what does DCEN Conversion mean?

State the objective, please, in complete sentences.

 

[Randy H]

He's converting his AC flux core wire machine to DC straight polarity.

 

[bob58o]

Hey wait, what does DCEN Conversion mean?

State the objective, please, in complete sentences.

Objective #1. Use A Bridge Rectifier to Convert the AC output of the Welder to DC - which is the recommended way to weld with flux core.
That is the "DC" part of "DCEN". Direct Current.

Objective #2. Make the Grounding clamp the positive lead. That leaves the welding electrode (gun) to be the negative lead. This is also the recommended way to weld with flux core.
That is the "EN" part of "DCEN". Electrode Negative. But it was AC before - so I am not "CONVERTING" it to Electrode Negative, just setting it that way.

That is it. DCEN. Direct Current Electrode Negative.
But the voltage is not smooth. It is not a constant Voltage

Objective #3. Use a capacitor to suppress voltage ripples. See the picture.

Objective #4. Use a 24-28V DC Fan to help cool the Bridge Rectifier and also bleed off the charged stored in the capacitor after the welder is turned off.

The bottom pic shows AC. The top Pic Shows DC, with and without a capacitor.

So I guess the objective is to keep the electrons flowing in a single direction at a steady rate while welding for an overall improved weld quality.

 

[ezcome-ezgo]

In short, he is GAB on his welder.

 

[bob58o]

Ordered some more stuff.
Got the fan and a fan grill/finger guard.

http://www.ebay.com/itm/EBM-Papst-4...e=STRK:MEBIDX:IT&_trksid=p2057872.m2749.l2649

http://www.ebay.com/itm/EBM-Papst-4...e=STRK:MEBIDX:IT&_trksid=p2057872.m2749.l2649

Edit: This is the grill
http://www.ebay.com/itm/Computer-Fa...me=STRK:MEBIDX:IT&_trksid=p2057872.m2749.l264

 

[ezcome-ezgo]

Those are 2 links to the same part. What does a grill like that set you back?

 

[bob58o]

Those are 2 links to the same part. What does a grill like that set you back?

My mistake.
http://www.ebay.com/itm/Computer-Fa...me=STRK:MEBIDX:IT&_trksid=p2057872.m2749.l264

$3.50 shipped

 

[bob58o]

Looks like it will fit. Think I'm going to attach the leads from the fan to the output terminals on the rectifier. Think that will be best. My plan is to use 4 pieces of #8-32 threaded rod each like 4.5"long to mount the fan in front of the rectifier outside the case. Have two nuts on the threaded rod tightened down with the side of the welder case sandwiched between. Another two nuts tightened against each other to set the distance for the fan. And lastly one nut tightened against the fan. So like 20 nuts. 16 washers?
I don't expect it to work very well so I'll probably have to add some more bracing....

Probably best to just show you later. I'm sure this description doesn't clearly portray what I'm trying to do. Maybe it does?

 

[bob58o]

I think they tried to deliver my capacitor, then left a note saying they are going to drop it at a UPS drop box. Why do I pay shipping if I have to go pick it up?

Added ring terminals to the fan. Hopefully I can easily add to rectifier positive terminals.
Red+
Blue-

 

[bob58o]

Much better than I expected.
Like a glove!

Planning actually pays off sometimes.

Only unexpected encounter was the nuts holding the threaded rod to the welder didn't clear the lip on the bottom of the welder case. I had to make some notches.

The fan is Positioned so that air is being pulled away from the welder/rectifier.

 

[bob58o]

Got it kinda put together.
Just need to work the wires to position the capacitor better.

 

[bob58o]

Off work tomorrow, so I should be able to test this out.

I turned it on once. It didn't blow up. The stock fan came on. I didn't try the wire feed. I didn't try to weld anything. I thought it was broken at first because my 24v fan didn't turn on. But guessing I need to weld something to get the current flowing out of the rectifier to power the fan????

Does that seem correct? Makes sense to me, but that is the answer I want so I may be BIASED. Electronics jokes are tuff! And not funny at all!

 

[bob58o]

Just pulling the trigger...
https://m.youtube.com/watch?v=d7n-ozqHAwE

---------- Post added at 02:29 PM ---------- Previous post was at 02:27 PM ----------

Actually welding...
https://m.youtube.com/watch?v=Ma9Dk8RQ-v4

 

[Kartorbust]

Have you done anything to help increase the duty cycle? I'm lucky with the flux cored/gmaw welder I have is already DCEN/DCEP, but the 20% duty cycle freakin sucks. Even though I have plans to buy a Hobart 210 MVP (or was it the 190?) to get more oomph behind it, still would like to get more than 2 minutes of continuous welding with my current rig.

 

[bob58o]

Have you done anything to help increase the duty cycle?

No, I don't think so. The DC fan may help it keep it cooler, but was really just to keep the rectifier cool. The way it is positioned in front of the vent slots should pull some hot air out of the case and pull hot air off the rectifier.

It is possible, that because of the rectifier, the Duty Cycle is even less. I've heard of rectifiers burning up. I don't really know.

---------- Post added at 04:03 PM ---------- Previous post was at 03:59 PM ----------

Perhaps the next modification... LOL
Replacing the stock fan with a more powerful one, adding another fan, ... anything to keep it cool should improve the duty cycle, right?
https://www.youtube.com/watch?v=ITtlxjvLQis

 

[Kentucky Boy]

I've had all the parts to do this mod sitting around for a while just haven't been able to get to it yet. I'm interested in seeing some pics of the welds you're able to pull off with these mods. I can hear the sound of bacon sizzling in your video, sounds like its operating much better than the stock welder. Got any pics of the welds? How's the splatter with the mods? I think when people burn up there rectifier it's because they bought the 100 amp rectifier which would be pushed to its limits by the 90 amp welder. The 150 amp rectifier should not burn up.

 

[bob58o]

I can hear the sound of bacon sizzling in your video, sounds like its operating much better than the stock welder.

Well I haven't really tried to weld anything yet. I just tested it make sure it worked and didn't blow up. I didn't really prepare the surface for welding in that video.

Got any pics of the welds? How's the splatter with the mods?

No and it seems better, but I haven't really tried it yet.

I think when people burn up there rectifier it's because they bought the 100 amp rectifier which would be pushed to its limits by the 90 amp welder. The 150 amp rectifier should not burn up.

Well THIS 150 amp rectifier is a 3 phase. I'm only using two of the three inputs, so not sure if it is good for 100 amps or for 150 amps. I should know this. But I don't.

 

[ezcome-ezgo]

I should know this. But I don't.

But bless your heart, you have a desire to learn, a yearning for knowledge. I have an apple for lunch.