Distributing large single-phase loads in limited-capacity 3-phase power systems

A LARGE single-phase load drawn from a limited-capacity 3-phase system will unbalance the 3-phase system. If analyzed by symmetrical components in the 3-phase system, equal and opposite positive- and negative-sequence currents are realized. This unbalance leads to excessive heating in the stator of the alternator, thus substantially reducing its over-all capacity. If uncorrected, the unbalance may also cause local hot spots in ordinary induction motors.