Standard AC Induction Motors are limited to fixed speed application even though the process can be run over a speed range. There are applications where, at times, the process can be run at lower speeds. In doing so, peak demand can be reduced and electric bills reduced by the energy savings. For such variable speed applications, a VFD or Variable Frequency Drive is needed. Inerter Duty Motors are designed for optimized performance to run with variable frequency drive which can operate for wide speed range without any heating problem. This motor has windings that can withstand harmonics and higher voltages and is also designed with proper cooling to run at lower speeds. Other features specific to the design of the inverter duty motor include • Extra heavy insulation in the slots • Extra end turn bracing • Double dip and bake polyester varnish