A generalized locus diagram for induction motors

It is well known that the construction of the induction-motor circle diagram presupposes the motor characteristic resistances and reactances to be constant. The paper discusses the variation of these circuit parameters and its influence on the current locus. It also provides a physical picture of conditions at starting and a simple technique for the construction of new `output¿ and `torque¿ lines, from which the machine performance may be computed over the whole speed range. The reliability of the method is indicated by comparison with experimental data.