Availability of quality power has become an important issue for industrial utilities due to frequent performance variations in process industries. Increase in the generating capacity has not kept up pace of power demand, which results into shortage of power supply and power system network is normally subjected to varying and unequal loads across the three phases. Continuous variation of single-phase loads on the power system network leads to voltage variation and unbalance, most importantly; the three-phase voltages tend to become asymmetrical in nature. Application of asymmetrical voltages to induction motor driven systems severely affects its working performance. This paper presents the effects of voltage variation and unbalance on the performance of an induction motor driven centrifugal pump with a case study.