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Thread: Question about duty cycle

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    Question about duty cycle

    After reading the post on the Pro Mig 180 (I have the same welder), I got to thinking about the duty cycle. I understand the "weld for 2 min, down for 8 min" concept, but I don't think I've ever experienced any issues, and I'm guessing that I've gone over that cycle. I'd say my cycle would probably be closer to weld for 5 seconds and down for 25 seconds, but I'm sure I've gone over that.

    Is working the machine harder than 20% just hard on the lifespan of the machine, or will it trip an internal breaker, or will it create a time paradox and the world explode?

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    Re: Question about duty cycle

    Watching.. I kinda understand duty cycle but also would like to understand it more. I know it incorporates several thing but like you haven't hit the duty cycle on either of my machines.

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    Re: Question about duty cycle

    Quote Originally Posted by Ron_J View Post
    After reading the post on the Pro Mig 180 (I have the same welder), I got to thinking about the duty cycle. I understand the "weld for 2 min, down for 8 min" concept, but I don't think I've ever experienced any issues, and I'm guessing that I've gone over that cycle. I'd say my cycle would probably be closer to weld for 5 seconds and down for 25 seconds, but I'm sure I've gone over that.

    Is working the machine harder than 20% just hard on the lifespan of the machine, or will it trip an internal breaker, or will it create a time paradox and the world explode?

    I too was curious after this duty cycle was mentioned. I pulled out my manual for my 225 amp Miller Ac stick welder. It has a 20% duty cycle @ 225 amps or two minutes of welding every 10 minutes, that to me seems pretty good for my type of welding here at home. Looking at the duty cycle chart of my miller I am running mostly 1/8' rod, so right around 130 amps. Now my duty cycle is 65-70%. In all the years I have had my Miller , I have never exceeded the duty cycle. Probably close to 35 years with that machine . It runs today as good as it did when new.

    With all this being said our Lincoln 180's are 30% @ 130 Amps , so 3 minutes of continuous welding @ 130 amps ,then 7 minute cool down .Duty cycle is based on 10 minute cycles . 3 minutes for me is a long time, so in reality I will probably never reach that. Nor worry about any damage. But I am curious to what happens, I would hope it just shuts down ,and does not self destruct.

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    Re: Question about duty cycle

    Quote Originally Posted by Mac's Crew View Post
    Watching.. I kinda understand duty cycle but also would like to understand it more. I know it incorporates several thing but like you haven't hit the duty cycle on either of my machines.

    Sent from my SM-G960U using Tapatalk

    Never even thought about duty cycle until I was in the process of buying this Lincoln 180. As said with that Miller of mine I can run @ 130 Amps for nearly 70% duty cycle ,wow thats 7 minutes, never timed it ,but how long does it take to burn a rod up. Heck the welding I do , I probably do two or three welds with one stick.

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    Re: Question about duty cycle

    Many machines usually shutsdown when duty cycle is reached . After a cool down period they will restart.
    Many users fit up, tack and weld and repeat.
    That's why most machines don't hit duty cycle. When everything is tacked up and you want to weldout, that's where there can be issues. Now you're welding steady and duty cycle can be met depending on machine amp capacity.
    Check duty cycle on the machine as mentioned. A 250 amp machine running at 110 amps will have a 100% duty cycle on lower amps


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    Re: Question about duty cycle

    Many machines do trip a thermal protection when the duty cycle is reached but this is not always the case. Be mindful of that. The thermal shut down can happen long after you passed the duty cycle, at which point some irreversible 'wear and tear' on electronics components might already have happened and the lifespan is appreciably reduced.
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    Re: Question about duty cycle

    If just doing hobby 20% duty cycle may work.
    I work look size of wire and material you are welding and that should be 60% duty cycle.
    If I was buying for work I look at 100% duty cycle.

    Remember look at chart on welder for 60% or 100% duty cycle some Manufacturer will show there 10%, 20% or 60% duty cycle on box.

    If need a Excel work sheet for calculating duty cycle I can email to you

    Dave

    Quote Originally Posted by Ron_J View Post
    After reading the post on the Pro Mig 180 (I have the same welder), I got to thinking about the duty cycle. I understand the "weld for 2 min, down for 8 min" concept, but I don't think I've ever experienced any issues, and I'm guessing that I've gone over that cycle. I'd say my cycle would probably be closer to weld for 5 seconds and down for 25 seconds, but I'm sure I've gone over that.

    Is working the machine harder than 20% just hard on the lifespan of the machine, or will it trip an internal breaker, or will it create a time paradox and the world explode?

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    Re: Question about duty cycle

    One reason for not hitting duty cycle issues is ambient temperature.
    As I recall, the duty cycle is rated at 104 degF (40 degC).

    When welding below that ambient temp the duty cycle increases. So in a 40 degree shop during winter, the duty cycle would be substantially higher.
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    Re: Question about duty cycle

    Quote Originally Posted by Oscar View Post
    Many machines do trip a thermal protection when the duty cycle is reached but this is not always the case. Be mindful of that. The thermal shut down can happen long after you passed the duty cycle, at which point some irreversible 'wear and tear' on electronics components might already have happened and the lifespan is appreciably reduced.
    Yep, I had a few lincolns that hit duty cycle a few times....too many then they shutdown permanently I finally switched to miller.... pretty sure the burned up ones weren't from duty cycle overuse.... well almost pertty sure

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    Re: Question about duty cycle

    Usually the small 225/125 transformer welders (lincoln, Miller) will start to run "cool" at the arc when they're getting too hot. You'll notice the decreased output.

    Lincoln will shut down in DC mode,, but won't shut down in AC mode (It just ruins the windings). NOt sure if the old Millers are the same (shrug)

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    Re: Question about duty cycle

    Quote Originally Posted by Ron_J View Post
    After reading the post on the Pro Mig 180 (I have the same welder), I got to thinking about the duty cycle. I understand the "weld for 2 min, down for 8 min" concept, but I don't think I've ever experienced any issues, and I'm guessing that I've gone over that cycle. I'd say my cycle would probably be closer to weld for 5 seconds and down for 25 seconds, but I'm sure I've gone over that.

    Is working the machine harder than 20% just hard on the lifespan of the machine, or will it trip an internal breaker, or will it create a time paradox and the world explode?
    I had a 150 amp, 220 volt Lincoln, and marveled that it never “hit” the duty cycle.
    I became noticing that the longer I welded with it, the colder it got.
    One day I took the cover off of it and found that the once honey-colored shellack in the wires was now molasses-colored.
    Apparently, the machine kept doing the best it could, as I violated the duty cycle.
    The newer models should shut off when they get too warm.

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    Re: Question about duty cycle

    The duty cycle is weeks link.
    Most time it is transformer it can be rectifier or engine.

    The wire insulation can be 50° or 60° C too there are other less common temperature too.
    Inc

    Dave

    Class Maximum Ambient Temperature (°C) Maximum Temperature Rise (°C) Hot-spot Over Temperature (°C) Maximum Winding Temperature (Tmax)(°C)
    A 40 60 5 105
    B 40 80 10 130
    F 40 105 10 155
    H 40 125 15 180

    Quote Originally Posted by MinnesotaDave View Post
    One reason for not hitting duty cycle issues is ambient temperature.
    As I recall, the duty cycle is rated at 104 degF (40 degC).

    When welding below that ambient temp the duty cycle increases. So in a 40 degree shop during winter, the duty cycle would be substantially higher.
    Last edited by smithdoor; 09-08-2020 at 01:44 AM.

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    Re: Question about duty cycle

    FYI
    Over sea like using insulation H
    It saves on copper or aluminum windings.

    Dave

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    Re: Question about duty cycle

    As said before the older machines had no protection from overheating. About 50 years ago I had a little 180 amp Miller in my school shop. Its duty cycle had been violated over and over. I was so glad that I was able to replace it with a 250 amp AC-DC miller that had all kinds of reserve power and a duty cycle of something around 50 % at 200 amps. Kids would never be able to cook it with 1/8th rods.
    The old machine I replace would weld for about half a rod then funny things would happen to the arc. It was cooked and someone phoned making an inquiry about the old welder thinking to purchase it from the school board. I warned him that it was a piece of trash and only worth the scrap copper.
    Generally it is wise to purchase as high a duty cycle as you can afford. Running up to the limit and relying on the thermal protection will eventually end in disappointment.

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    Re: Question about duty cycle

    Quote Originally Posted by Ron_J View Post
    After reading the post on the Pro Mig 180 (I have the same welder), I got to thinking about the duty cycle. I understand the "weld for 2 min, down for 8 min" concept, but I don't think I've ever experienced any issues, and I'm guessing that I've gone over that cycle. I'd say my cycle would probably be closer to weld for 5 seconds and down for 25 seconds, but I'm sure I've gone over that.

    Is working the machine harder than 20% just hard on the lifespan of the machine, or will it trip an internal breaker, or will it create a time paradox and the world explode?
    2 mins does not sound like long time but stare at yer watch for 2 mins. Any Geerage welding will NOT be 2 mins long.


    as you mentioned, weld, reposition, weld, repeat.
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    Re: Question about duty cycle

    Quote Originally Posted by Broccoli1 View Post
    2 mins does not sound like long time but stare at yer watch for 2 mins. Any Geerage welding will NOT be 2 mins long.


    as you mentioned, weld, reposition, weld, repeat.
    You are correct. 2 minutes is a long time...
    Welds last longer than Love...

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    Re: Question about duty cycle

    How long is a minute? It depends on which side of the bathroom door you're on. A 1/8" rod takes about a minute to burn.

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    Re: Question about duty cycle

    Quote Originally Posted by smithdoor View Post
    If just doing hobby 20% duty cycle may work.
    I work look size of wire and material you are welding and that should be 60% duty cycle.
    If I was buying for work I look at 100% duty cycle.

    Remember look at chart on welder for 60% or 100% duty cycle some Manufacturer will show there 10%, 20% or 60% duty cycle on box.

    If need a Excel work sheet for calculating duty cycle I can email to you

    Dave
    Hey Dave why not post it here or in a new thread, if not I'll pm you my email address, I wouldn't mind having it but have a fair idea of what mine is.
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    Re: Question about duty cycle

    I am working off my phone the does let me upload and it is in Excel file.
    I have email a copy you.
    It may let you upload if put in a zip file.

    Please post any where.
    It is on
    https://groups.io/g/Welding

    Dave

    Quote Originally Posted by CAVEMANN View Post
    Hey Dave why not post it here or in a new thread, if not I'll pm you my email address, I wouldn't mind having it but have a fair idea of what mine is.

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    Re: Question about duty cycle

    The AWS provides the formula for calculations.
    This could be put in a spreadsheet if a person wanted, or just work it by hand.
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  26. #21
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    Re: Question about duty cycle

    Yes I have Excel spreadsheet on duty cycle
    If you message me your email address I will send you copy.

    Dave

    Quote Originally Posted by MinnesotaDave View Post
    The AWS provides the formula for calculations.
    This could be put in a spreadsheet if a person wanted, or just work it by hand.
    Name:  Screenshot_20200920-103848_Drive.jpg
Views: 90
Size:  111.1 KB

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