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of these waves is very small, and as the frequency is high, satisfactory lighting can be done directly from the generator with no battery connected to the circuit. The generator is connected to the battery, however, and all lights and other electrical devices take their current from the battery terminals. The arrangement of the voltage regulator is such that a discharged battery is charged at a rapid rate while the charging rate tapers off as the battery becomes charged. This is clearly shown by the curve sheet C-4,

mobile Power Plant.

at Fig. 219. It will be observed that at the beginning of the charging process with the battery practically discharged, a charging rate of 16 amperes was obtained, at the end of one hour, but 14.2 amperes were delivered to the battery. At the end of three hours the charging current had tapered down to 11.3 amperes. At the end of eight hours but 61⁄2 amperes was flowing to the battery. In thirteen hours time the minimum charging rate of 434 amperes had been reached.

In the constant voltage equipment the automatic switch, voltage regulator and field resistance unit are mounted in an alu

minum box carried at the top of the generator, as shown in Fig. 220. This box is held in place by a single knurled nut and by three connecting pins or plugs which fit into receptacles in the generator. The two wires leading from the generator are soldered into a connecting plug, which in turn fits into a receptacle of the regulator box. The regulator mechanism can be changed readily by anyone, as no electrical or mechanical knowledge or skill is

Fig. 224.-Wiring Diagram Showing Circuits of Bijur-Hupmobile Starting and Lighting System.

required. In Fig. 221 the regulator box is shown with the cover removed, which exposes the automatic switch and the field resistance. This also shows an end view in which the connecting pins are shown, and a view of the disconnecting and reversing plugs also. An amperemeter is used in some of the Bijur systems, such as that at Fig. 168, B, which shows the wiring diagram of a Packard six-cylinder car, and in Fig. 222, which shows the system used on the Packard Twin Six. The amperemeter is con

R

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.