Transient Thermal Performance of Busways at High Values of Overload Current for Short Periods of Time

A useful method is presented for quickly evaluating the thermal performance of busways or other conductors for applications at high values of overload current for short periods of time. In many cases, such as resistance welder applications, the ampere rating required for the busway is equal to the overload current times the square root of the duty cycle, but sometimes a larger busway is required. It is important to evaluate the thermal performance by a method based on the thermal time constant of the busway such as the method presented in this paper.