nected between the generator and the battery and shows only generator output. Whenever the engine is running the meter should indicate, and its failure to do so gives prompt notice that there is trouble.

The Bijur two unit systems are subjected to a division on account of the starting motors that are used, there being two types, geared and direct acting. In the geared type, double reduction gears are included between the starting motor and the engine flywheel. An over-running clutch is included in the gearing. In the direct acting type the motor pinion meshes directly with the flywheel teeth, the double reduction gearing and roller clutch being omitted. The motor has a square shaft and a pinion having a correspondingly broached hole can be moved horizontally on the shaft into and out of mesh with the flywheel. The motor shown in Fig. 220 is of this type. The direct acting motors can also be used in connecting with the Bendix drive in which a screw shaft carrying a weighted pinion provides for automatic shifting. The standard voltage for the Bijur two unit equipments is 6 volts, though these have been manufactured in 12, 16, and 18 volt systems.

A variety of starting switches are manufactured, these usually being selected according to the form of starting motor used. The usual type is provided with a preliminary contact which connects the battery and starting motor through a resistance located inside of the switch. This preliminary contact is made just prior to meshing the starting gears and flywheels and causes the motor to rotate at low speed and with little power, so that proper meshing of the gears is insured without any liability of stripping them. The switches may be direct acting or indirect acting. That shown at Fig. 220 is a direct acting switch having a foot-operated plunger which is intended to project through the floor board. Depressing this heel button makes the two switch contacts, and also shifts the gears into mesh with the flywheel through a mechanical interlock provided for that purpose. In the indirect acting type the starting switch is connected through a system of linkage to a starting pedal located at the driver's seat. Switches are also made in which no preliminary contact is used. The method of meshing the gears

with the single contact switch is illustrated at Fig. 160 in the preceding chapter. The mounting of the generator, motor and starting switch for the Hupp Model N car is clearly outlined at Fig. 223. The complete wiring diagram for the Hupp, which shows the manner in which the various units are connected together, is shown at Fig. 224. In this system ignition is by the battery through the conventional short contact timer and distributor and induction coil. In the Apperson System, outlined at Fig. 216, a high tension magneto is used for ignition. This is also the type of ignition used in connection with the starting and lighting system of the Model 21-A Winton Six, shown at Fig. 225.

Bijur-Packard System.-The self-starting and lighting system, Fig. 168, B, used on the 1915 six-cylinder Packard, is manufactured by the Bijur Motor Lighting Co. In this system the starting motor and generator are separate units. The starting circuit is simple, consisting of a motor connected directly to the battery and operated by closing a starting switch.

In the generator circuit the principal parts are: The generator; an automatic switch for breaking the circuit when the speed of the generator becomes so low that the battery current would discharge through it, and a voltage regulator of the vibrator type. A study of the wiring diagram shows that the automatic switch has two coils, a voltage coil of high resistance connected across the wires leading to the battery and a current coil in series with the generator and battery. The action of this coil is such that as the armature speed increases and the voltage becomes greater, the magnetism generated in this coil attracts a small steel arm, thus completing circuit between the battery and the generator. Current then flows to the battery and lights.

On the other hand, as the speed of the generator decreases, its voltage becomes less and finally a point is reached where the current begins to flow back into the generator. This reversal of flow produces a magnetic field in the series coil of the cutout which opposes the field produced by the voltage coil, until finally the attraction of the latter for the steel arm that completes the circuit is entirely overcome and then the arm, impelled by a spring, breaks contact.

The voltage regulator operates on the vibrator principle, and is designed so that when the voltage becomes higher than the predetermined amount the vibrator throws a resistance into circuit that reduces the amount of current flowing through the field, as has been previously described. Nothing in the wiring is unusual and the diagram may be easily followed in view of the complete explanation previously given of the Bijur systems.

Fig. 226.-Simplified Wiring Diagram Showing Action of Simms-Huff Starting and Lighting System.

The Simms-Huff Single Unit System. The operation of this one unit system differs from the Dyneto in that the wiring arrangement is so designed that the non-stalling feature is eliminated. The simplified wiring diagram which is presented at Fig. 226 shows that this system operates on the one wire method, and that the wiring is such that a 12-volt series battery arrangement is used in starting while the 6-volt parallel charging scheme is followed. The starting switch, which may be either foot- or handoperated, automatically controls the battery connection and pro

vides a wiring scheme for the lighting circuit which insures healthy battery action and makes for minimum fluctuation in candle power when the motor, for instance, is being cranked with the lights burning or at the other extreme when the engine is raced. Through the inherent winding arrangement, when the motorgenerator is used for starting, it. automatically becomes a 12 volt cumulative compound motor which on being driven by the starting of the engine becomes a differential dynamo and charges the batteries at a predetermined rate which can be varied by a single regulator adjustment that is easily made.

The small diagrams in Fig. 226 show the inherent winding arrangement which automatically accomplishes these results. On

Fig. 227.—Curve Showing Current Output of Simms-Huff Generator.

examining the directions of the arrows it will be seen that the eurrent which the arrows represent flows in the opposite direction in the series field when charging than it does when starting. The action of the powerful field winding is to assist the motor when starting by increasing the strength of the magnetic field and to weaken the field strength of the dynamo when charging and prevent an overcharge at high speed. In this manner it automatically assists the regulation of the charging current delivered to the battery. The charging current increases from zero to its maximum with a very small increase in car speed. This is clearly shown in the graphical diagram at Fig. 227, as this outlines the