Abstract: An improved capacitive discharge ignition apparatus provides spark advance with engine speed. The ignition apparatus includes at least one trigger circuit including a trigger coil preferably contained in a common housing with other circuit elements. In this case, an auxiliary coil may be provided to cancel certain pulses in the trigger coil output that could otherwise interfere with desired operation. In some embodiments, a second trigger circuit is provided to derive a triggering signal from the primary coil of the ignition's step-up transformer. A triggering signal of appropriate magnitude received from either trigger circuit will cause discharge of an energy storage element through the primary coil.

Abstract: An improved capacitive discharge ignition apparatus includes disable circuitry for permitting shut-off of the engine. The disable circuitry includes a SCR and a transistor in series to provide a bypass for current that would otherwise charge the ignition capacitor. The SCR is gated by a RC circuit charged by momentary contact of a user-actuated switch. The transistor is rendered conductive only during periods when a positive voltage is induced on the charge coil, thereby limiting discharge of the RC circuit. In addition, the RC circuit is regeneratively charged by a leakage current through the SCR gate. The disable circuitry thus achieves engine stoppage regardless of the time required.

Abstract: An improved capacitive discharge ignition apparatus includes disable circuitry for permitting shut-off of the engine. The disable circuitry is operative to gate the discharge SCR, thereby shorting current that would otherwise charge the storage capacitor. A portion of the charging current is diverted through a transistor to the SCR gate. The transistor is rendered conductive for a predetermined time by a RC circuit connected to its base. The RC circuit is charged by momentary contact of a user-actuated switch. The time constant of the RC circuit is preferably selected to achieve engine stoppage under any anticipated operating conditions.

Abstract: A discharge ignition apparatus for use with a small internal combustion engine has built-in overspeed disable capability. At operating speeds below an overspeed threshold, revolution of a magnet assembly past a stator unit having a magnetically permeable core causes accumulation of charge across a storage capacitor. When the capacitor has reached a fully charged state, a triggering signal is applied to the gate of a SCR device to cause rapid discharge through the primary coil of a step-up transformer. The higher voltage produced at the secondary coil of the step-up transformer is then applied across the gap of a spark plug. At operating speeds exceeding the overspeed threshold, a second trigger circuit renders the SCR conductive prior to substantial accumulation of charge across the storage capacitor. The second trigger circuit includes a zener diode or other voltage threshold element in circuit with a trigger coil operative to produce a speed dependent voltage signal.

Abstract: A method and apparatus are provided for determining angular alignment between a lamination stack, a commutator, and coil windings of an armature for an electric motor. The apparatus has a body with an aperture for extending about the commutator, and a post for fitting into the lamination stack to locate an indicator slot and graphic symbols relative to the lamination stack for visually comparing alignment between the lamination stack, the commutator, and the coil windings.