TO 



AUTOMOBILES. 



pr 



vehicle to the nearest station, which may be miles 

 away. 



If it were not for these defects, electricity would 

 he the ideal power for vehicles. The problem of 

 getting a greater mileage from the electrically 

 propelled vehicle has been attacked from a differ- 

 ent direction, however, and the remedy consists 

 in saving a part of the current and making it do 

 work where it is now wasted., at the same time 

 longing the life of the batteries. This method 



s* devised and patented by Frank K line, an 

 electrical engineer of New York city, who was 

 one of the earliest inventors in this line, and has 

 proved successful. The Hae electric automobile 

 differs from the ordinary in the design of the 

 motor and the method of its control, the object 

 U-ing chiefly to obtain a very high efficiency in 

 starting and accelerating, while at the same time 

 maintaining the average efficiency at maximum 

 >|M'eds. 



The electric automobile depends for its energy 

 upon the storage-battery, and the motor should 

 In- doigned to meet the limitations imposed by 

 the battery. The makers of storage cells, of 

 whatever type, are careful to state the rate of 

 discharge for the best conditions of operation, and 

 to give a maximum rate of discharge that should 

 not !K> exceeded. The usual design of motors for 

 automobile work is based upon maximum-speed 

 conditions, and in starting and accelerating such 

 a motor, the current consumption during this 

 period is from two to three times greater than is 



time in accelerating, and reaches speed with a cur- 

 rent consumption little if any above the normal 

 discharge rate of the cells. This is accomplished 

 by a motor design in which the starting torque 

 is' produced by a large number of field turns and a 

 small current, and by a system of regulation 

 whereby the effective turns are decreased to in- 

 crease the speed. 



Below is a diagram showing the several com- 

 binations of field windings to produce this re- 

 sult. The motor is of the railway type, one motor 

 only being used on the vehicle. It is geared to the 

 rear axle by a simple differential gear, having one 

 reduction, and is so arranged that the axle is con- 

 tinuous and is not weakened by dividing as is 

 usually done. The tests upon one of the Rae 

 cabs weighing approximately two tons, over a 

 measured mile of level boulevard, gave the result 

 shown in the table: 





RAE'S SYSTEM OF MOTOR CONTROL. 



required to operate the motor at maximum speed. 

 It therefore follows that a motor ordinarily de- 

 signed to utilize nearly or quite the rated dis- 

 charge of the battery when operating under full- 

 load and full-speed conditions, will require, to 

 start and accelerate this load, a battery discharge 

 of two or three times the rated output of the 

 battery. 



In practical operation in city streets, an auto- 

 mobile consumes a very large part of its time in 

 starting, stopping, and accelerating, again slow- 

 ing down and getting under headway, so that in 

 ordinary practise tfoe total energy taken from the 

 battery for this work is greater, and the rate of 



than is the case when the motor is operating under 

 maximum-speed conditions. 



The Rae system of design and control obtains 

 a high starting efficiency, without sacrifice of 



Whatever the speed made by the cab for the 

 test distance, the watt-hours consumed were prac- 

 tically the same that is to say, for a given dis- 

 tance the watt-hours per ton-mile for the machine 

 tested averaged about 

 82 at any speed from 

 6 miles to 12 miles an 

 hour. 



The 4 - per - cent, 

 grade is ascended at 

 about 6 miles an 

 hour, while the cur- 

 rent draft is about 42 

 amperes, which is 

 well within the dis- 

 charge rate . of the 

 cells. In the cab with 

 which this test was 

 made the battery was 

 rated at 125 ampere- 

 hours at 80 volts, or 

 10,000 watt - hours. 

 The radius of action 

 was therefore 52 

 miles. The machine 

 has repeatedly made 

 50 miles on boulevard 

 and asphalt roads. 



The Riker vehicles 

 are driven by an 



equipment which consists of 2 motors, each con- 

 nected to a driving-wheel that turns freely on a 

 stationary axle. The latter is in one piece, making 

 the vehicle very strong. The motors are pivotally 

 secured to the axle and suspended from the side 

 bars. In some cases there is an advantage in 

 using but one motor, which must therefore turn 

 both rear wheels, and must be geared to them in 

 such a way that either of them can turn inde- 

 pendently of the other while rounding curves. 

 To do this some makers cut the rear axle in 

 halves, and connect the halves with the compen- 

 sating gears. In this vehicle the compensating 

 gear is placed in the left-hand rear hub, making 

 the rear axle as strong as with the 2-motor meth- 

 od. This enables both methods of driving to be 

 used, without sacrificing strength or simplicity. 



Within a radius of 30 miles, and within New 

 York city, charging stations are erected where 



