The world of welding can be a very confusing space for people who are just getting familiar with the basics. There are a lot of terms that look complicated and intimidating but in reality, they are fairly easy concepts to grasp. It is important in your welding journey for you to get familiar with all the details regarding welding. It is not enough just to know how to weld but it is also important to understand the technical reasoning behind everything.
Duty cycle is not something which is constant and can vary a lot depending on variables like amperage and voltage you are using along with the welder you own etc. Keep it as a factor while choosing the welder you want to buy. Duty cycles depend on the welder being used and you should be abel to find the duty cycle from your machine’s manual.
WHAT IS WELDER DUTY CYCLE?
The duty cycle as a phrase might sound very fancy but in reality, it is quite simple. It simply represents the safe operating time of a welder within a given time frame. The timeframe it is measured in is 10 minutes. So for example, if your duty cycle is stated 70% on 100 amps, it means you can run the machine for 7 minutes at 100 amps before the machine gets too hot.
The duty cycle is not stable or constant though, it can change a lot depending on the amperage you are operating it at and even the climate at which you are welding.
The duty cycle can be compared to production cycles in industries that measure the same thing but in terms of output not the running time of the machine.
If you ever come across a label or a description stating that this welder has a duty cycle of 50% at 200 amps then it simply means that for every 10 minutes that the machine is on, it will safely operate for 5 min at 200 amps. This duty cycle will change if you change the amperage you are working at and varies along with the temperature of your workshop. For example, welding in cold weather, you can run the welder for longer periods before it starts hurting your machine’s transformer or inverter.
For most welders, if you lower the amperage it will increase the duty cycle. The reasoning behind this is simple, working at a lower amperage will produce less heat and therefore the machine can work for longer periods of time.
WHY DO WELDING MACHINES HAVE A DUTY CYCLE?
Welding machines work at high temperatures and amperes. Making them work in these conditions for long periods of time will end up heating the machine. Duty cycle is important to know for how long can you use that machine without it becoming dangerous not just for the machine but for you as well.
Usually, there are safeguards present in the machine itself to prevent overheating. This needs to be done in case anyone keeps operating the machine above the prescribed time. An overheating welder can cause electric shocks, short circuits and they might even catch on fire.
WHAT’S A REASONABLE DUTY CYCLE FOR A WELDER?
Before we get into determining a reasonable duty cycle it is important to understand whether the duty cycle is a good factor to judge a machine by.
The answer here is not straightforward, duty cycle is one of the factors which you should look at while buying a machine but it is not the only one. The first thing to look for is whether the duty cycle stated with the machine is correct or not, a lot of times manufacturers overstate the duty cycle of a machine.
One thing to keep in mind is that going solely on duty cycle is like buying a car solely on its top speed, it does not paint the total picture. The next thing you should consider is the welding technique you are going to be using the most. The duty cycle can be a significant factor when it comes to MIG welding because it does not require a lot of downtime as opposed to stick welding.
It does not matter so much in TIG and stick welding. You should also take a look at the efficiency and the output of the machine along with the duty cycle.
A lot of machines might have a higher duty cycle but as you increase the amperage the price of a welder goes up as well. There are a lot of factors when it comes to deciding the performance of a particular machine.
REASONABLE DUTY CYCLE
There is no one answer to this question, it depends on what you are using it for.
For example, when it comes to stick welding a duty cycle of a machine does not matter a lot. There is a very simple reason for this. In stick welding you don’t really turn on the machine for long periods of time, changing electrodes and sometimes chipping off slag might require you to stop welding from time to time. Because of this reason, duty cycles are usually much lower and not even needed as much as for MIG. A decent duty cycle for stick welding can be around 30%.
For the most part, TIG also does not require high duty cycles, this is because of the kind of work it is usually used on. Thinner materials and smaller parts, usually involving detailing, etc. you end up turning the machine on and off a lot. A lot of times TIG systems are used on low amperage which automatically increases the duty cycle.
MIG requires higher duty cycles because it being a semi-automatic process designed to increase the output. You can see duty cycles reaching above 60-70% regularly.
All in all, while considering what’s a reasonable duty cycle for your new machine first get clear what type of method you are going to use as well as how thick material you are going to weld regularly. Thicker materials need more volts and amps thus if you are buying a 140 amp machine and you’ll be running it close to maximum settings most of the time, it might be a good idea to get a machine with higher specs.
WHAT HAPPENS IF I RUN WELDER OVER THE DUTY CYCLE?
Most of the welders being manufactured today have an automatic system where they stop working when the internal temperature goes above a certain limit. If you are wondering what temperature is increasing as you weld, it would be your transformer or an inverter, depending on the machine you are using. Some of the welders will even turn themselves back on when they have cooled down enough.
HOW TO CALCULATE DUTY CYCLE?
If you are unable to find the prescribed duty cycle on your welder from the manufacturing there is a simple way for you to find out the duty cycle of your machine to a fairly decent degree.
Run your machine for a certain amount of time, on certain settings, either 5 or 10 minutes, and see how long the machine can actually operate before shutting down. It is not the best way to test, but if you really need to know the answer, you can try it. The process is not done here. You will have to keep in mind some of the variables which can affect the running time of the machine.
Even the weather you were testing it at can make a difference. If you tested the machine in a colder climate then the duty cycle might be a bit higher because the machine will find it easier to cool down and to remain cold. On the other hand, while working in a warm temperature the duty cycle might come out to be lower.
Whatever the time period the machine was working for, represent that in percentages, and voila! That’s the duty cycle for your machine.
One more variable which might miss your mind is the life of the machine. If it is new or you are turning it on after a long time then the duty cycle will be higher while if the machine had been operating before the test it will most probably be lower.
INVERTER VS TRANSFORMER WELDERS DUTY CYCLE
Inverters are thought of as being more efficient machines and some of the machines out there only use about half the amperes to achieve the same results. Although inverters are considered more efficient it is still a fairly new technology so it will take some time to know the long-term implications of them. But as of now, inverters have almost always better duty cycle if compared head to head with a welder in the same class.
It has to be said that a lot of old-school welders still prefer transformers over inverter welders because they are believed to be more durable and last for a longer time.
FREQUENTLY ASKED QUESTION
Duty cycle will definitely be one of the factors you will consider while purchasing a welder and therefore, it is important to have everything clear about this topic otherwise you might end up buying a machine which doesn’t suit your needs. I will try to address some of the most common queries related to the topic.
As I stated before there is no ‘good’ duty cycle, it depends upon the technique you are going to be using and the usual amperage you work with. A good number to aim for is at least 30% in my opinion, depending on the material you are going to be welding.
Yes, this is due to the fact that welders will find it easier and faster to cool down and even slower to heat up in the first place. This will give the welder more time to operates before it overheats.
MIG technique is more automatic when compared to stick and TIG, you don’t have to constantly feed the wire manually, neither do you have to change the electrode or stop to remove slag. This usually makes you run the machine for longer periods of time.
To sum it all up, duty is important but does not completely determine the performance capabilities of a welder. They simply represent the time period for which they can operate within a given time frame. The duty cycle also fluctuates with amperage being used and the ambient temperature being operated at. Keep in mind that duty cycles are much more important for MIG welding when compared to TIG and Stick. It is also fairly easy to calculate the duty cycle of your device if you don’t know. And a lot of the newer machines have an automatic fail-safe in case you go over the suggested time limit.