Reliance Electric has introduced three RPM AC series totally enclosed inverter duty motors with finned frame construction. The FL 180, FL210 and FL250 designs are engineered to provide increased torque density and more power in a smaller package. The FL210 and FL250 products incorporate a patent pending, laminated steel frame design with integrated fins. The compact design is said to reduce rotor inertia and provides a higher torque-to-inertia ratio, which delivers continuous constant torque from base speed down to zero speed.