Asymmetrical 3Ö Induction Motors Under Single-Phase Feeding: Oscillating Torque, Theoretical and Experimental Analysis- Harmonic Effects.

The three-phase asymmetric induction motor is an excellent solution in rural areas where only single-phase system exists. In those cases very often it is desired to drive mechanical loads which power is well beyond the maximum economical power limit for single-phase induction motors. A typical problem faced by farmers in Brazil. The three-phase asymmetric induction motor follows the same design pattern in a production line for the ordinary three-phase squirrel cage induction motor, estimated production costs doesn’t change substantially in both cases. The unique differences for both motors are the number of windings in two of the stator phases and the capacitor between the open phase and one of the connected phases. With stator windings Y connected, the asymmetric induction motor can have a single-phase source applying voltage “V” " between 2 of the terminals, with an auxiliary capacitor “Cap”, this extra component solves the starting problem and improves the performance at nominal operating point condition. Figure 1 illustrates the induction motor and its connections. Figure 1. Schematic diagram of an asymmetrical three-phase induction motor.