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.For example, a 150 amp. welder with a 30% duty cycle must be rested for at least 7 minutes after 3 minutes of continuous welding.(When you are paying an employee for welding, anything less than 100% duty wastes money.).f you buy a ZENA welder, you won't need a 250A welder to get 150A, 100% duty performance! ALL ZENA welders are rated at their 100% duty cycle power ca pability.