There is some confusion in my mind as to the terms you have used in your question. Resistance (US engineering) generally refers to DC ohmic values, and when I measured a generator winding resistance, I used a 4 terminal kelvin bridge. This measured the DC resistance of the copper only. The test procedure’s that you describe would be the proper procedures for measuring the combined I2 R winding and core losses which is a means of providing a value of merit of the machine. This is not resistance alone. It includes the complex power loss of all the 3 phase windings plus the core losses. (hysteresis) ALSO Note, this measurement does not include any friction or wind-age losses. Does this help you any?