Need help for a welding machine modification project (Please come in and help me.)

[windson]

I am doing a project to increase the duty cycle of this machine.

I wish to know whether the output current of this machine is AC or DC?

How do I improve this machine duty cycle ? (increase the machine duty cycle, make it can perform welding for longer time)

Please post your idea, I am very appreciate your help!

Link below was the use manual of this machine from manufacturer.

http://www.weldingweb.com/attachment...2&d=1188892654

[fun4now]

generally the best you can do is give it a large enough cord to supply the welder the needed power. if you need an increased duty cycle and it is doing what the book said it should, you need a new bigger welder. the duty cycles is the welders limits before shut down due to over heat. too small of a circuit or power cord or extension cord will decrease the duty cycle, but you cant increase the manufacturers settings. if its not getting you the recommended duty cycle then look at the above mentioned problems such as cord, circuit, extension cords to get you the rated output.generaly a welder is what it is, if you need a higher duty cycle you need a larger welder to get you a higher duty cycle.
hope that helps and welcome to the site.

[6010]

The machine looks like it is an AC only. It shows AC output on the work cables and the diagram does not show the necessary components for the rectification necessary for DC output.

This is a very basic machine per the drawing, as it doesn't show a control to change the current output. It could be done by changing taps on the transformer, but the diagram does not show that.

The only way to change the duty cycle on this machine would be to increase the size ( capacity) of the transformer. This is the most expensive component in this machine so I don't think it would be cost effective. The only other way would possibly be to increase the air flow across the transformer by installing a different fan, but this would probably only be a marginal increase in capacity. The heat that would kill the transformer is in the middle of the windings of the transformer and is limited by the design of the transformer to withstand a certain amount of heat generated by the design output current and duty cycle, taking into consideration the heat carried away by the fan air on the outside of the transformer.

You would probably be able to run the unit a little longer in cold weather if you were outside. The colder the weather the more you could increase the duty cycle, but again this would be only a marginal increase unless you are way up north in the middle of winter.

45 percent sounds like a pretty good duty cycle for a simple welder like this. In my experience if someone is doing repair work, this duty cycle is adequate for most repair jobs.

[6010]

Excuse me !! It is a little early for me since I stayed up so late. I see the tap on the transformer now, so you can change the output current but you only have the two settings.

[windson]

The machine only have two selection of output current (either high current and low current), but how do i make it to be an adjustable output current?

I am considering add a fan (total 2 fans) to this machine, will this increase the duty cycle of the machine?

I also got an idea to attach a heatsink at the welding transformer, will it help to increase the heat exchange and increase the duty cycle?

[BWS29128]

The specs list DC output at approx 25VDC at 115A. Am I missing something there?

For the little I know about this stuff (most of which was learned last week, darn it!) it would appear that you would be better off buying a new machine rather than attempting to modify this one so extensively.

I agree with 6010 that a larger transformer would increase the output, but as he said that's the most expensive part. I can't imagine that a fan would give you very much increase, although a larger or additional fan might be a REQUIREMENT if you install a larger transformer......not sure about that either.

[6010]

The two fans would certainly improve the heat transfer but how much I couldn't tell you. Like I said before what really matters in the transformer is the heat in the middle of the windings where the heat and the electrical stress is greatest. This is more a function of the basic design of the transformer and cannot be improved upon at this point.

To make the current more adjustable the only practical way would be more taps - again a basic design change that you cannot improve on at this point. You have two settings now, 115 amps and 138 amps. This is a 20 percent change which sounds like a lot but I don't think I could tell the difference in 115 amps and 138 when I am stick welding.

I hate to tell you this but it looks like if you want something better than what you have you will need to buy a new welder.

Too bad I didn't get your post a month ago. I gave away a Lincoln Buzz Box that I bought back in 1975. It was strictly AC but was better than what you have now, and probably better than the comparable welders in its class today. I would have sent it to you if you had paid the freight. I would have even paid the freight if I had known you were young and on a tight budget, but I have already given it away. It hadn't even been used much. I only welded up the bottom of a horse trailer and made a deer stand with it. It is just that I bought a T Bolt for the DC and then got a Synocrowave and needed some room.

Sorry I couldn't help you out.

[Steve]

For a project, It could get interesting. First measure the time before the unit temps out and record the time. Now measure the air flow the one fan has at the transformer and add fans to double the air flow. Next get some really big heat sinks, put heat sink compound and the sinks all round the transformer core. Follow this with a 24,000 btu air conditioner putting out 40 degree air ducted to the input fans. Get some 1/8 in rod and start burning till the thing temps out or melts down. Record time for comparison to first time. Walla project complete. If you have more money, hermeticusly seal everything and dump the unit in a vat of liquid helium repeating the timed test.

[Goodhand]

For a project, It could get interesting. First measure the time before the unit temps out and record the time. Now measure the air flow the one fan has at the transformer and add fans to double the air flow. Next get some really big heat sinks, put heat sink compound and the sinks all round the transformer core. Follow this with a 24,000 btu air conditioner putting out 40 degree air ducted to the input fans. Get some 1/8 in rod and start burning till the thing temps out or melts down. Record time for comparison to first time. Walla project complete. If you have more money, hermeticusly seal everything and dump the unit in a vat of liquid helium repeating the timed test.

ROTFLMAO!! Thanks, Steve, I needed that.

[windson]

**Follow this with a 24,000 btu air conditioner putting out 40 degree air ducted to the input fans. **


pls tell me what is btu air conditioner putting out 40 degree air ducted??

if can, please give me the photo for reference..

thank you for your help..

[fun4now]

its just not feasable to try to increase the duty cycle

it would be less $$ to just buy a new unit.
nothing realistically can be done to increase a duty cycle. air temp will effect it, but as a hole it is what it is due to design. if you need 100% duty cycle you just have to get a welder with a higher top end to give you 100% at the amp you need. if you need 135amps at 100% Duty cycle you need to buy a 200amp welder, its that simple. no shortcuts just design and function.
you just need to work slower of get a larger welder. i suspect heat sinks could help a little but if you want to spend big $$ to increase the duty cycle just buy a water cooler and attach it to the heat sinks to reduce the core temp. again spending more $$ to fix this one than it would be to buy a new larger welder.
if its about available wall power, than you need to look at inverters to get you more output per wall amp. i had to get an inverter as i could only offer a welder a 30amp 240V circuit. again i am still limited to the duty cycle of the inverter and would never consider opening it up to try to increase the duty cycle. no space to play inside it any way. but in the winter i do get better cycle times (due to colder air being pulled threw it)

[windson]

this is a project, i cant just buy a new welder.. the project objective is increase the duty cycle of this machine. please help me what can i do to increase the duty cycle of this machine? give any idea do you have..
thank you very much.

[Old Sporty]

Windson - Please don't take this the wrong way, but your answer is in the previous posts.

When a transformer is designed, it is designed for a particular temperature range. If you exceed this range for any length of time without interruption devices in place, the winding will fail and you will have a paper weight.

The only way you can increase the duty cycle (load limit) of a transformer is to supercool it. You would achieve some capacity increase though how much I don't know. This, however, isn't a perfect world either. Too cold and insulation becomes brittle and with heating of the core and expansion it too will fail. Without knowing the electrical engineering approach this unit was designed around, it is not possible to tell you what these limits are.

You mention this is a "project". Without getting too personal, would this be for school or a personal quest? Either way, good luck.

[SundownIII]

Windson,

Where are you writing from? It would help to know where you're coming from.

With regards to your question about whether the output was AC or DC. It is DC. The specs you published showed 25.5 Vdc @115A and 26 Vdc @ 138A. Can't imagine what's so difficult about that.

Not trying to be a smarta$$, but you seem to have trouble understanding English.

Several posters have already stated (and correctly so) that it is not feasible/possible to significantly increase the duty cycle of the welder in question. Welders are "designed" to produce a certain output at a certain duty cycle. Components are designed to work in consonance with one another. As soon as you start "beefing up" one component, another component down the line fails.

Your question has been answered, you just don't like what people are saying.

PS Your other posting regarding preparation, combined with this post, leads me to believe you've got a lot of reading/study to do before you're ready to strike the first arc. With that said, what's the big deal about "duty cycle"?

Later

[fun4now]

if i had to increase the duty cycle for a project be it a school thing or a bet with a Friend i think i would make some heat sinks with water channels so i could use a cooler to run cold water threw the heat sinks attached to the transformer.
some aluminum heat sinks set up to use water to help cool attached to the transformer and then add a standard welding torch cooler to cool the water. many easy ways to build a cooler and the heat sinks could be as simple or complicated as you saw fit.
best of luck.