Final answer:
To determine the minimum feeder conductor size for five 30A motor generator arc welders with a duty cycle of 30 percent, you need to calculate the continuous load and the non-continuous load. The minimum conductor size for this setup is #4/0 AWG.
Step-by-step explanation:
In order to determine the minimum feeder conductor size for five 30A motor generator arc welders with a duty cycle of 30 percent, we need to consider both the continuous load and the non-continuous load.
The continuous load is calculated by taking 100% of the largest welder's current rating, which is 30A, and multiplying it by the number of welders (5). So, the continuous load is 30A * 5 = 150A.
The non-continuous load is calculated by taking 100% of the remaining welders' current rating, which is (30A - (30A * 30%)) = 21A, and multiplying it by the number of welders (5). So, the non-continuous load is 21A * 5 = 105A.
To determine the minimum feeder conductor size, we need to add the continuous load and the non-continuous load together: 150A + 105A = 255A.
Based on the NEC (National Electrical Code) guidelines, we can use Table 310.15(B)(16) to find the minimum conductor size. For a 255A load, a #4/0 AWG conductor would be suitable.