Too many sophisticated morn users competing for limited available power and distribution capacity, cause significant voltage fluctuations and power interruptions.

The mains voltage may vary from +/- 10% to +/- 25% in many countries.

Standard AC drives, rectifiers & electronic controllers are not designed to withstand such a wide input voltage window. The likely result is lower reliability and/or equipment failure possibly leading to unscheduled downtime, and increased costs for maintenance and repair.