What is duty cycle?

What is duty cycle? Duty cycle is a welding equipment specification which defines the number of minutes, within a 10 minute period, during which a given welder can safely produce a particular welding current.

In example, a 150 amp equipment with a 30% duty cycle must be "rested" for at least 7 minutes after 3 minutes of continuous welding.
If a machine is rated at 300 amps/60% duty cycle, it can weld at 300 amps for 6 minutes. For the remaining four minutes, the power source needs to idle and cool.
Keep in mind, however, that the actual total time while a machine can be used continuously is not determined by a timer. Typically this is determinate by a thermostat within the machine, which will shut it off if the machine is too hot and needs to cool down before it does more work. Factors affecting duty cycle include whether or not the machine has an internal fan and what the ambient temperature of the work area is.

Highlight on duty cycle:
Don't make the mistake of comparing a commercial duty of a professional equippment with an hobbstic. The second equippment may promise high welding currents, but it's limited by low duty cycle performance.

Look carefully the specifications of your equipment:
Many manufacturers will identify a particular welding equipment by its maximum possible power generation capacity. Anyway, that welding equipment may only be able to produce that level of power for a short period of time.
However, careful reading of the documentation that comes with the unit may show that the welder can only produce this rated power with a 10-20% duty cycle (or even less). There is a huge difference between this welder and another 200A welder that can produce its rated power continuously (100%), first of all on term of work capability.

Highlight on duty cycle:
All CEA machines data are given at 40 °C according to EN 60974-1 standard and they are tested in an advance climatic chamber for the most precise test possible.

Moreover, another important details is the ambient temperature of which technical data a referred.
All CEA machines data are given at 40 °C according to EN 60974-1 standard and it’s quite easy to understand that any technical data referred to a lower temperature (e.g. 25°C) give higher duty cycle than those declared at 40°C as imposed by the standards.
Now you have all the information for better understanding the important thematic of duty cycle.

Don’t mix them up and be careful in any comparison!

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