Understanding Duty Cycle and IP Class in Welding Machines

What Is Duty Cycle in Welding? 

Duty cycle is one of the most misunderstood specifications in the welding industry.

It refers to how long a welder can operate at a certain amperage within a 10-minute window. For example, a 60% duty cycle means you can weld for 6 minutes, then the machine needs to rest for 4 minutes while still plugged in and powered on so the cooling fans can run.

But here's what most explanations leave out:

These numbers are based on an ambient temperature of 104°F. That means the air being blown through the machine to cool it is already hot 104°F and it's trying to keep internal components from exceeding 150°F. As you can imagine, blowing 104°F cooling air over hot electronics isnt very effective.

Now imagine using the same machine in a shop thats 70°F. Suddenly, the cooling system is much more effective, and the actual duty cycle improves significantly.

When duty cycle testing is done properly under strict conditions with regulated temperature and humidity the results can be sobering for many machine manufacturers. There are industry standards that must be followed, and when they are, the true performance of a machine becomes very clear.That said, most of us aren't welding every day in 104°F heat. And even if we are, we as operators rarely run at 100% ourselves in that kind of weather so theres some balance between lab numbers and real-world use. 

How does IP class play into that?

What Is an IP Class?

Imagine your welding machine is wearing armor to protect it from water and dust. That armor has a score like a video game and that score is called the IP class.

IP stands for Ingress Protection, which is just a fancy way of saying How good is this thing at keeping stuff out?

What Do the Numbers Mean?

An IP rating looks like this: IP65 or IP23 Its always IP plus two numbers:

The first number tells you how good it is at blocking dust or solid stuff. 0 = No protection

6 = Totally dust-proof!

The second number tells you how good it is at blocking water. 0 = No protection

8 = Can go underwater and still work!

Example:

IP23 means:

2 = Its protected from big stuff like fingers or tools

3 = Its safe from light rain or water spray

IP67 means:

6 = No dust can get in awesome!

7 = You can drop it in a puddle, and itll still work

So that being said, a lot of welding machines are IP21. That is a very poor rating in a real life scenario. But this allows for good airflow, no obstructions to keep water out, no louvers obstructing flow the machine gets good cooling. 

Also, the board design is different. In a welding machine, you want the boards to be lacquer coated. Lincoln Electric® calls that Vault Technology it keeps metal dust out of the chips and prevents the board from frying easily. Of course, you dont see this on machines from Lincoln worth less than $10,000.