Electrical equipment of gasoline automobiles

The relative merits of various ignition devices are discussed and the use is advocated of an induction coil operating from a constant-potential circuit in connection with a device which will limit the current at low speeds and still permit sufficient current flow at the higher speeds. A variable-contact device is used to operate the coil at its most efficient point and this eliminates to a considerable extent the necessity of manual control of the firing point. This ignition system produces a spark no matter how slowly the engine is turned over, thus lending itself particularly to electric motor starting. A lighting generator should be capable of supplying current equivalent to the average lamp load, when the car is running at a speed of fifteen miles per hour. The method of regulation advocated is a demagnetizing series coil in the battery circuit, thus maintaining constant charging current. The lighting circuit is so connected that the current to the lamps will not pass through the series coil, thus tending to maintain a constant charging current independent of the lamp load. For starting purposes two schemes are possible, namely, the use of the lighting generator as a motor, or the use of a separate motor. The separate starting motor is advocated and its characteristics are discussed.