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sacrificing efficiency or durability. The simplest designs are cheaper to manufacture and are not so apt to give trouble to the user. The single unit system is much simpler than the two-unit system and it is much easier to install because there is but one machine to set up, drive and wire up. The simplicity of the oneunit system means that there is but one set of bearings to oil, but one pair of brushes (if the device is the single commutator type), one simple and direct connection by silent chain and simple wiring.
The application of the one unit system to the chassis of a White car is shown in the plan view of the chassis at Fig. 184. The motor-generator is attached to a substantial bracket, back of the gear box and is connected to the engine by a driving shaft carrying a sprocket at its forward end just ahead of the shaft supporting bearing, this being in connection with a large sprocket attached to the engine flywheel, as shown at Fig. 185 by a silent chain. The storage battery is carried on the other side of the chassis frame just forward of the rear axle. To start this form of a one-unit system a switch is moved from the “off” position to the "start" position and it is left there until one desires to stop. In the White system the control switch is mounted on the steering column, as shown at Fig. 185. The Dyneto single unit system has no relays, automatic switches, overrunning clutches, sliding gears or current regulating devices. The usual manner of installation is to drive the motor generator with a silent chain so that the device turns at three times the motor speed. As the tendency is towards small bore, high speed motors, it is necessary that these be cranked over fast as they do not start easily at speeds of rotation below 100 r. p. m. The Dyneto-Entz starter will crank a four cylinder 234 inch bore x 442 inch stroke at a 172 r. p. m. on a six volt system drawing 40 amperes. A six cylinder, 344 inch ore x 542 inch stroke is cranked over at 140 r. p. m. on a 12 volt system drawing 35 amperes from the battery. It is said that less energy in watt hours is required of a storage battery at the high cranking speed because while the current output may be a little more, the time that the current is required to flow is much less in securing a positive start than it would be at the lower cranking speed.
One of the distinctive features of the Dyneto System is that it is non-stalling. This makes driving in traffic perfectly easy without changing gears every time the car is slowed down. This is because when the engine tends to run slower than a certain number of revolutions the device ceases to be a generator and becomes a motor, automatically drawing current from the storage battery instead of putting current into it. It is contended by those who
Fig. 185.—View at Left Shows Simple Control Switch of Dyneto-White
Starting and Lighting System. Rear View of Motor at Right Shows
do not favor the one unit system that the non-stalling feature makes a serious drain on the battery. It is said that no current is drawn from the battery at speeds above 8 m. p. h. and that very little is taken at any lower speed at which the car can be driven. When any current is drawn from the battery back through the motor-generator, the series field is strengthened and as this causes an increase of voltage it prevents to a large extent a back flow of current. The device changes from a motor to a generator at 5 miles per hour, and at a speed of 242 m. p. h. a point that
would never be reached except momentarily in traffic, a current of 10 amperes is drawn from the battery.
This back flow when it does occur is turned to advantage by preventing the gasoline engine stalling. It is necessary to take very fully into account the characteristics of the various motors
to which the machine is to be fitted and proportion the windings accordingly. It may be desirable on a car having a certain gear ratio to have the back flow occur at a somewhat higher speed than
on another car. These COMMUTATOR
factors are taken into A
consideration in designing the various systems. A number of curves are given at
Fig. 186 showing the FO
motor characteristics of a 12 volt Dyneto size B. It will be observed by consulting the upper diagram that
in this case the device B
changes from a motor to a generator at a
speed of 712 m. p. h. IGNITION
If the speed is inMAGNETO creased above this fig
ure the machine becomes a generator and charges
the storage battery. If the speed decreases the device
becomes a motor and CHAIN DRIVING
draws current from SPROCKET
the storage battery. Fig. 187.—The Dyneto One Unit Motor-Gen
It will be observed erator at A and Latest Method of Installing that the Maximum It on Franklin Engines Shown at B.
current output of 121/2 amperes is produced when the engine is turning over at a speed equivalent to 171/2 m. p. h. From this point the current output falls so that at 4712 m. p. h. but six amperes are being generated. At 600 r. p. m. the machine delivers .6 h. p. and is working at 60 per cent. efficiency. Similarly, if used as a generator