Combined Trolley and Accumulator System for Driving Electric Cars.
Year: 1895

page_text: COMPLETE SPECIFICATION.
Combined Trolley and Accumulator System for Driving
Electric Cars.
1, THEODOR NEES, Technical Student, of 25 Louisenstrasse, Munich in the
Kingdom of Bavaria, German Empire do hereby declare the nature of my
invention and in what manner the same is performed to be particularly described
and ascertained in and by the following statement :-
The present invention consists of a process for combining the trolley and
accumulator systems, for driving tram cars by electricity.
The trolley system whether employed with overhead or underground conductors,
is inconvenient and difficult of application in narrow streets having many turnings
and is in many cases objectionable, when overhead conductors are employed on
account of the unsightliness of the latter, which are in addition to this-subject
to breakage and to the damaging influence of frost and other atmospheric changes.
On the other hand the accumulator system, increases the weight of the car to a
great extent and the accumulators must be constantly charged at stations arranged
for the purpose, rendering working with this system very expensive.
According to the present process, the trolley system is only employed in straight
broad streets and the current which drives the car is simultaneously employed to
charge a small light secondary battery by means of which the car is driven short
distances, whilst the trolley system may be interrupted, for instance through small
and narrow streets having many turnings said secondary batteries being arranged
advantageously under the seats of the car.
At such points where it is not advisable to continue the overhead conductor, the
same may be carried forward underground in the form of a cable, and during this
period the car will be driven by switching in the accumulator, or secondary
battery which has mean time been charged.
By means of the present invention the overhead conductors may be omitted at
such points where they may be objectionable owing to unsightliness, then again the
possibility of disturbances and interruptions in working are rendered less, since the
secondary battery may be employed at any time whilst the weight of the car is
much less than that of an ordinary accumulator car, the secondary battery being
but small and the necessity of charging the secondary battery through special
stations is obviated.
And in order to make the present Specification more easily intelligible reference
is had to the accompanying drawing in which similar letters denote similar parts
throughout the several views :-
Fig. 1 is a side elevation showing the application of the invention in a street the
overhead conductors being interrupted and continued for a certain distance as
cable.
Fig. 2 is a similar elevation showing how the conductors may not be interrupted
but stop at the end entirely as at C.
Fig. 3 shows a car having the motor and battery connected parallelly and
Fig. 4 one in which the motor and battery are connected up in series,
Fig. 5 shows a car having a dynamo motor.
M represents the motor suitably connected to the car axle R. S is the secondary
battery, 1 in Figure 4 a switch and D in Figure 5 a dynamo, adapted to work as an
electro motor at times, for which however may be substituted the thicker coil of a
so called motor-dynamo. In carrying out the process a small light secondary
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page_text: battery is arranged under the seat of the car, which may be connected up either
parallelly or in series with the electro motor which drives the car and thus be
charged or which may be charged indirectly by means of a motor dynamo. As
the secondary battery will only have to store sufficient power to keep the car
running from about 10 to 30 minutes at a time, the same need only be about one
tenth to one twentieth the weight of the ordinary accumulators, as employed in
the accumulator car driving system.
In order to obviate the necessity of employing a battery having several cells,
the charging and discharging of the same may be effected by means of a second
thicker coil on the armature of the car motor. The current which is about
500 volt. strong would develope the mechanical power for driving the car in the
thinner coil of the armature whilst simultaneously the current of any desired less
tension developed in the thicker coil would serve to charge the battery.
An automatic switch device for maximum and minimum may be employed to
control the running so that the battery can only be charged when the car is
running at a certain speed, and thus when the secondary equivalent current must
have attained a corresponding tension.
Generally it appears to be more advantageous to charge directly without a motor
dynamo by connecting up the motor and a battery of several cells parallelly. In
the case of increase in the current when applying the brake and starting, the
currents of the battery and the conductor main may be employed simultaneously.
The variations in the current would then be less than with the ordinary contact
system. Disturbances in the main conductors would not have such serious
consequences as with the trolley system. The installation cost would be generally
less than those of other systems.
Instead of the overhead conductors it is obvious that I can employ underground
conductors equally well.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is performed I declare that what I
claim is :-
A combined trolley and accumulator system for driving street cars consisting in
employing the energy supplied by the main conductors to the motor to drive the
car in wide straight streets and simultaneously to charge a small secondary battery
arranged in the car, said secondary battery serving to drive the car in small or
short streets, the main conductors being continued underground during such
period, until they can be again continued overhead.
Dated this 24th day of April 1895.
BOULT & WADE,
Agents for the Applicant.