Capacitor have been use for decades to operate 3-phase motors on single-phase power. Two single-phase wires are connected to two of the inputs on a 3 phase motor on this method. Then, the capacitors is connected to one of the single -phase inputs and the third leg of the motor. Here is the schematic diagram of the circuit:

Enabling 3 Phase Motor Operates with Single Phase Supply circuit schematic

The voltage is allowed to be displaced in time from its parent voltage by phase shift through the capacitor. Voltage distinct from the 2 single-phase lines is the result. The motor will operate if the capacitors value-it’s ability to process electrical current- is sufficient.

6 times as much current to start as it does to run is required by the motor so a static-capacitor phase converter must have some means of switching a large group of capacitors in and out during motor starting. Below is a typical unit uses a potential-type motor starting relay (pirated from a single-phase motor) to regulate the larger start capacitor, while a smaller (in value) capacitor provides continuous power to run the motor. The potential relay removes the start capacitor from the circuit as the motor speed increase, and the motor operates. [Circuit's schematic diagram source: gwm4-3phase.com]