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proper degree of tension to insure positive drive without whipping, such as results when a chain is run too loosely. A wiring diagram of a 24-volt starting but 12-volt lighting system is given at Fig. 210.
The Northeast motor-generator is said to be a one unit machine in every sense of the word, as it is only one field, one armature, and one set of brushes. The armature has only one winding and
Fig. 214.—How the North East Motor Generator May Be Installed on
Four Cylinder Engines.
one commutator, and is the only moving part in the system. The automatic battery cutout is embodied in the motor-generator. This reduces wiring complications and makes the motor-generator a complete machine, contained in one housing. The motor-generator weighs about 40 pounds, and is approximately 65/" in diameter and 1012" long. It is capable of spinning a 334" bore, four-cylinder engine over 200 r. p. m. In common with most single unit systems, the driving ratio between the motor-generator and the engine is such that this is usually driven from two and a half to three times the engine speed. A 24-volt 35-ampere hour battery is called for by this system. The motor-generator is connected by only two wires to the storage battery, and it is said that these can be connected without regard to positive or negative polarity. The starting switch also has but two connections to the motor-generator which may be connected without regard to polarity. The system is so designed that no damage will result from operating the starting switch while the engine is running. The connections required are extremely simple as the wiring diagram indicates. The four leads running from the motor-generator are of heavy wire, those going from the storage battery to the machine being of No. 4 cable while those running from the machine to the starting switch are of No. 6 cable. The lamps operate on a three wire system, and while the storage battery delivers 24 volts to the motor-generator but 12 volts is put into any one of the lighting circuits. Fourteen volt lamps are used throughout the system.
The Northeast Universal System has been designed to make possible the installation of this starting unit to old model cars in which no special provisions are made for installing such a system. The sectional view at Fig. 211 shows the method of carrying the motor generator and how it is connected to the engine crankshaft by a countershaft carried beneath the unit. It is designed to go at the front of an automobile, being carried by special brackets which are adapted for almost any standard car. The method of carrying the Northeast Universal System is clearly shown at Fig. 212. The countershaft projecting from the driving sprocket is attached to the engine crankshaft in any suitable manner. A common method of installation is to have the end of the countershaft fit a coupling member that takes the place of the usual cranking dog. The way this is done in case of the Marmon Model 32 car is clearly shown in the sectional diagram at the lower part of Fig. 213. The upper part of this figure demonstrates the simple installation of the unit at the front of the car.
The motor-generator is completely encased, as is the driving chain; there is no opportunity for dirt to collect around the parts of the mechanism. When applied in this manner the engine crankshaft is turned over in exactly the same way as it would be by the hand crank, which, of course, is replaced by the countershaft assembly driven from the electric machine. The front end of the countershaft is provided with a conventional form of clutch to make it possible to crank the engine by hand in exactly the
Fig. 215.-Wiring Diagram of Bijur-Scripps-Booth One Unit Starting and
same manner as is ordinarily done after the starting crank is properly engaged. As the starting crank is only used in cases of emergency where the battery has become depleted or where some trouble exists in the electrical machine, it is made detachable so that it can be carried in the tool box. The Northeast Universal System functions in exactly the same manner as the built-in system designed for specific makes of cars.
Bijur Starting and Lighting Systems.—Three types of Bijur Starting and Lighting Equipments are manufactured; the simplest is the single unit, in which one machine acts either as a motor or generator, as conditions demand. The motor-generator equipment is generally chain driven from the crankshaft at a ratio of approximately three to one. This type of machine assumes the function of a generator at about 100 r. p. m., so that with ordinary rear axle ratios the generator function takes place and the battery begins to charge at low car speeds. This machine is provided with a shunt and series winding which act differentially when operating as a generator and cumulatively when operating as a motor. The voltage of the generator is variable as the regulation is for current. At low speeds, the current is maintained sub
Fig. 216.-Wiring Diagram of Bijur-Apperson Two Unit Starting and
stantially constant, but diminishes at high speed. The regulation is effected by the differential action of the shunt and series field, and also by reason of the fact that the shunt field is connected between one of the main brushes and an auxiliary or regulating brush.
As shown by the diagram at Fig. 215, which shows the electrical equipment on the Scripps-Booth car, no automatic switch is used. Connection between the motor generator and the battery is made with a hand switch, and the motor-generator draws current from the battery until the gas motor begins operating under its own power and acquires a speed sufficient to drive the electrical unit at a speed of about 1,000 r. p. m. As this corresponds to an engine speed of about 330 r. p. m., the carburetor throttle is usually adjusted so the engine cannot be throttled down to a speed below the cut-in point of the motor-generator. This is done to eliminate the non-stalling feature and to prevent the battery
discharging when a car is left standing idle. The Bijur one unit system is designed to operate on 12 volts.
There are two two-unit systems, one of these having a series starting motor and constant current generator. The other has a constant voltage generator and series motor. Considering the former the constant current generator is a shunt wound machine, the regulation being effected by the shunt field being connected between one of the main brushes and an auxiliary or regulating brush. The units are self-contained and require no separate mounting or connecting of the automatic switch, which is mounted inside the aluminum housing on the commutator end of the machine. These machines are reversible and the connections between