Protective systems for starter mechanisms in motor vehicles are known in the art. Protection is desirable in order to prevent damage which may otherwise occur if the starter is overrun, or re-energized after the engine is running. Starter protector or lock-out systems typically sense some function of engine RPM during the starter sequence and automatically remove electrical power to the starter motor when the engine attains an adequate RPM level to be running. Starter disconnect circuits are known which respond to intake manifold vacuum, oil pressure, frequency of an AC generator voltage, etc., to disable the starter at a predetermined engine RPM.
Starter control systems are also known in which after starter lock-out, the relay is maintained open until the engine speed falls to practically zero. Other starter protectors are known which require manual intervention for restart. Mechanically sequenced starter switches are also known.