Circuit for generating a rotating field for a three phase synchronous motor serving as a flywheel starter for a vehicle internal combustion engine

Claim 1

In combination with a brushless, three phase synchronous motor and an internal combustion engine having a flywheel, said motor acting as a driving motor for a flywheel wherein said flywheel is capable of coupling as a flywheel starter for said engine, said motor having a stator rigidly connected to stationary elements of said engine and a plurality of field windings, and a winding-free toothed rotor rigidly connected to said flywheel and having a pole pitch angle, a circuit for generating a rotating field for said field windings comprising: ferromagnetic sensor means positioned proximate said toothed rotor for generating signals indicative of the pole pitch time of said rotor; divider circuit means coupled to said sensor signals for generating a current flow signal for each field winding in response to said sensor signals, said current flow signals having equal time duration, and the sum of the durations of said current flow signals being less than said pole pitch time; and delay network means coupled to said divider circuit means for determining a time delay between the start of said pole pitch time and the start of said current flow signals which is optimal for the prevailing operation of said motor.