dubbed a "double decker." The wiring diagram is shown at Fig. 244.

The two armatures are connected together by a train of gears and an overrunning clutch, so that the gears and motor armature are in operation only when the starting switch is pressed. Incorporating the reduction gearing and overrunning clutch of the starting-generator unit in an oil bath, insures silent operation during starting, as external gears and the meshing of the same are entirely eliminated.

The unit has only one drive shaft and is connected to the engine by an Oldham coupling. This allows of quick and easy removal from the engine for inspection if necessary, although large inspection plates are provided on the unit itself, which is conveniently and accessibly located on the engine. Although the frame for the two units is a steel casting, the magnetic circuits are entirely independent, as may be seen from the illustration. The generator is shunt wound and is automatically regulated for constant current by a vibrator, which is mounted on the same base with the relay or electric cutout. The function of the regulator is to keep the output of the generator constant regardless of the speed of the engine. The relay is simply an electric switch which opens and closes the circuit between the generator and battery automatically to prevent dissipation of battery current in the generator when the engine is at rest.

The motor is of the conventional series type and is wound to withstand heavy overloads. Armatures, brush holders, fields, etc., are built in accordance with standard electrical practice. The generator windings are protected against injury by means of a fuse located on the relay-regulator base. Should the battery become. disconnected either through accident or neglect, this fuse will burn, thus protecting generator and field against excessive voltage, which would result if the field circuit were not opened.

To start the engine the operator presses the starting switch, which puts the motor armature into motion, engages the gearing and clutch, and turns the engine over. When the engine is running under its own power the clutch and engine are automatically disengaged and the unit operates only as a generator. The lamp

load of the car is carried by the generator at about 12 miles per hour. As a "tell-tale" an indicator is employed, from which the operator may determine whether the generator is working properly. A simple lighting switch is used for turning on any combination of lamps. No side lamps are used, as the head lamps contain small independent bulbs for signal lamps. The two-wire system of wiring is used. It has been carefully developed, resulting in a very simple layout, as may be seen from the accompanying wiring plan of the system as applied to the six-cylinder National car.

Generator.

The Westinghouse Systems.-The Westinghouse systems operate on the regenerative principle, i.e., when the engine is not running or when it is running at a very low speed the current load is taken by the battery and the power thus absorbed is returned to the battery when the car is running at usual speeds during the day. The generator has an output at average car speeds sufficient to carry an ample lighting equipment without drawing on the battery for power. The Westinghouse generators are compact and are intended to operate at the usual magneto shaft speed. They can be connected directly to the driving shaft with an ordinary Oldham coupling, and the design is such that the center line of the armature shaft is at the usual magneto shaft height. When a generator

attains a speed higher than that at which it generates the battery voltage, an automatic switch inside the generator automatically connects the generator to the circuit. This switch is so adjusted that it disconnects the generator at a speed about 25% lower than the "cut in" speed, the difference in speed between "connection" and "disconnection" provides against the switch operating "in" and "out" continuously when the car is running at the speed at which the switch closes the circuit.

As is common in other systems mentioned the generators are of two types with respect to the regulation of output. In one the current supplied by the generator is regulated inherently by the winding of the machine, the control of the voltage depending upon the storage battery. In the other type an automatic potential regulator which forms part of the generator keeps the voltage constant and regulates the battery charge. The Westinghouse generators can be furnished with or without ignition parts. Where the ignition is incorporated with the generator, as at Figs. 245 and 246, the general construction follows closely that of other battery ignition systems in principle as the battery current is transformed in an induction coil to a value sufficiently high to overcome the resistance of the air gap at the spark plugs. The interrupter is mounted on the generator shaft and the contacts are operated by a centrifugal device that automatically times the degree of spark advance to the speed of the engine. The distributor is of the usual face plate type but specially designed so the distributor plate can be placed in position without interfering with the contact brushes and without the use of tools. The internal wiring of the ignitiongenerator is shown at Fig. 247.

The various forms of Westinghouse generators have been previously described. All the Westinghouse motors are series wound. and are entirely enclosed. The rectangular shape is followed in some which makes them easily located and permits the rigid mounting. The motors may have integral planetary reduction gearing or may be provided with shafts to permit of mechanical or automatic shifting of the pinion with the flywheel gear. The starting switches are of two types, the mechanically actuated and the magnetically operated types.

Fig. 246.-Showing Arrangement of Ignition Parts of Westinghouse Ignition Generator Unit.

The Westinghouse starting motor using the automatic gear shift is made in two patterns, as shown at Fig. 248. One of these, known as the inboard, is so mounted that rotation of the armature shaft draws the starting pinion toward the motor. The outboard design illustrated below it is so arranged that the pinion is shifted away from the motor when the armature starts to turn. Obviously, the way the pinion will shift is determined by the angularity of the spiral thread. If the thread is right handed the pinion will be

Fig. 247.-Wiring Diagram of Westinghouse Ignition Generator.

shifted in one direction, if left handed it will be moved in the other. The inboard type of motor is intended for use where the flywheel is exposed while the outboard form has been designed for attachment to the flywheel case of a power plant having an enclosed flywheel. The two switches are also shown in this illustra

Fig. 248.-Two Types of Westinghouse Starting Motors and Operating

Switches.