How to choose the right motor for cranes, hoists and material handling On paper, a crane duty motor and a general purpose motor of the same kW rating can look almost identical. In service, they behave nothing alike. Fit a standard motor to a crane or hoist and it will overheat, lose insulation life and fail long before its time. Understanding why comes down to one idea: power rating tells you how much a motor can do; the duty cycle tells you how long it can do it without over