What does duty cycle mean for welding equipment?
Duty cycle (ED for short) is the maximum permissible operating interval of a welding unit. In order not to damage or destroy the welding equipment, a rest period must be inserted after this specified period. The duty cycle can also be used to assess the load or overload capacity of a device and thus its quality.
ED in percent
On some devices, several specifications for different ampere values are given. The period of use is usually indicated in addition to the percentage. If this value is not specified, the period of use is usually 10 minutes. In the homework sector, only a short duty cycle is usually required.
In contrast, expensive welding equipment for commercial use usually has a very high ED of up to 100%. Such equipment can be used in combination with the specified ampere value for quasi non-stop operation.
Example for duty cycle with time-of-use
A short example with period of use: 80A / 50 % ED S2 30 min. means that at 80 Ampere welding current after 15 minutes of welding work a break of 15 minutes must be taken. When buying a welding machine, the ED is an important factor, which is given as a percentage. 50 percent ED means that welding can be carried out with the welding device for five minutes and the device must then cool down for five minutes.
Non-stop welding with 100 percent ED
100 percent duty cycle offers the possibility of welding without a break, but this is only possible with reduced current. The conversion of the mains voltage into welding voltage does not take place physically without losses, which is related to the so-called internal resistance of the conductor.
The duty cycle is the ratio of welding time and cooling phase
In principle, the following rule applies to welding equipment: the higher the ED, the fewer welding breaks. The standard EN 60974-1 applies to the determination of the duty cycle for professional welding equipment, while the standard EN 50060 applies to the equipment for hobby and limited use.
Until recently, the specified temperature was 25 degrees Celsius, a temperature that corresponds to the average use in Central Europe. In the meantime this ambient temperature has been increased to 40 degrees Celsius. The specified duty cycle must be observed during welding to avoid damaging the device.