Discussion on “interaction of synchronous machines”, at Niagara Falls, N. Y., June 25, 1907

Any paper which tells in a simple way how to calculate the characteristics of two machines in parallel is valuable, especially when the equations or diagrams give the synchronizing power. From this we can determine the stability and the natural period of the machine, in other words we can predict something about its hunting tendencies. I doubt, however, if this paper will give this information and I ask Professor Brooks for some explanations. Professor Brooks uses the reactance and the resistance in the total circuit. It must be remembered that machines having the same synchronous impedance, which means substantially the same synchronous reactance, have widely different characteristics. For instance, a machine of definite pole construction and a given synchronous impedance may have an angular displacement of the armature at full load of 15 degrees, whereas another machine of the round rotor type having substantially uniform magnetic reluctance may have 30 degrees displacement with the same impedance. It is obvious therefore, that any calculations based upon the reactance are of little value in determining its characteristics.