Timing circuit for flywheel ignition system

An arrangement in a flywheel alternator for use with an electronic ignition system of an internal combustion engine having:

• a rotor provided with a plurality of circumferentially located radially polarized permanent magnets;
• at least one stationary power coil oriented in magnetic circuit relationship to the rotor magnets;
• at least one stationary trigger coil oriented in magnetic circuit relationship to the rotor magnets;
• and
• means for electrically coupling the coils to an electronic ignition system
• wherein the improvement comprises
• the rotor having an odd number of magnets with an adjoining pair of the magnets of the same radial polarity, the remaining adjoining pairs of the magnets of opposite polarity, the trigger coil having a dimension with respect to the permanent magnets to bridge two of the magnets each of which adjoins a common third one of the magnets, the power coil having a dimension with respect to the magnets to bridge magnets having a North-South or South-North orientation of their radially inward pole faces a number of times equal to one less than the total number of magnets,
• whereby in the sequence of magnetic circuits formed by the magnets bridging the trigger coil a unique pulse suitable for firing an electronic ignition system is generated exactly once each flywheel revolution and in the sequence of magnetic circuits formed by the magnets bridging the power coil substantial power is generated.