A power supply system comprising: a regulated power source having a synchronous machine with a flywheel, said flywheel being mounted to a common shaft, said synchronous machine comprising: an excitation stator winding; an excitation rotor winding cooperative with said excitation stator winding, said excitation rotor winding rotating with a rotation of said common shaft of said regulated power source; a main stator winding; a main rotor winding cooperative with said main stator winding and rotatable with the rotation of said common shaft of said regulated power source; a voltage controller electrically connected to said excitation stator winding so as to cause a voltage to develop in said main stator winding so that power flows out of said regulated power source as said flywheel rotates; and a rotating rectifier affixed to said common shaft of said regulated power source, said rotating rectifier cooperative with said excitation rotor winding and said main rotor winding; an electrical generator electrically interconnected to said regulated power source, said electrical generator having a shaft therein; an engine having a main shaft integral with or coupled to said shaft of said electrical generator; a mains power supply; and a switch connected between said electrical generator and said mains power supply and said regulated power source, said switch transferring power from said regulated power source to said electrical generator so as to cause said electrical generator to rotate said shaft of said electrical generator in order to rotate said main shaft of said engine, characterised in that the power supply system further comprises: a squirrel cage winding cooperative with said main stator winding and said main rotor winding, said squirrel cage winding being rotatable with the rotation of said common shaft of said regulated power source. a regulated power source having a synchronous machine with a flywheel, said flywheel being mounted to a common shaft, said synchronous machine comprising: an excitation stator winding; an excitation rotor winding cooperative with said excitation stator winding, said excitation rotor winding rotating with a rotation of said common shaft of said regulated power source; a main stator winding; a main rotor winding cooperative with said main stator winding and rotatable with the rotation of said common shaft of said regulated power source; a voltage controller electrically connected to said excitation stator winding so as to cause a voltage to develop in said main stator winding so that power flows out of said regulated power source as said flywheel rotates; and a rotating rectifier affixed to said common shaft of said regulated power source, said rotating rectifier cooperative with said excitation rotor winding and said main rotor winding; an electrical generator electrically interconnected to said regulated power source, said electrical generator having a shaft therein; an excitation stator winding; an excitation rotor winding cooperative with said excitation stator winding, said excitation rotor winding rotating with a rotation of said common shaft of said regulated power source; a main stator winding; a main rotor winding cooperative with said main stator winding and rotatable with the rotation of said common shaft of said regulated power source; a voltage controller electrically connected to said excitation stator winding so as to cause a voltage to develop in said main stator winding so that power flows out of said regulated power source as said flywheel rotates; and a rotating rectifier affixed to said common shaft of said regulated power source, said rotating rectifier cooperative with said excitation rotor winding and said main rotor winding; an engine having a main shaft integral with or coupled to said shaft of said electrical generator; a mains power supply; and a switch connected between said electrical generator and said mains power supply and said regulated power source, said switch transferring power from said regulated power source to said electrical generator so as to cause said electrical generator to rotate said shaft of said electrical generator in order to rotate said main shaft of said engine,