Edison, His Life and Inventions [350]
etc., were given to me, and my work was to design the supporting frame, axles, countershafts, driving mechanism, speed control, wheels and boxes, cab, running board, pilot (or `cow-catcher'), buffers, and even supports for the headlight. I believe I also designed a bell and supports. From this it will be seen that the locomotive had all the essential paraphernalia to make it LOOK like a steam locomotive.
"The principal part of the outfit was the electric motor. At that time motors were curiosities. There were no electric motors even for stationary purposes, except freaks built for experimental uses. This motor was made from the parts-- such as fields, armature, commutator, shaft and bearings, etc., of an Edison "Z," or 60-light dynamo. It was the only size of dynamo that the Edison Company had marketed at that time.... As a motor, it was wound to run at maximum speed to develop a torque equal to about fifteen horse-power with 220 volts. At the generating station at Menlo Park four Z dynamos of 110 volts were used, connected two in series, in multiple arc, giving a line voltage of 220.
"The motor was located in the front part of the locomotive, on its side, with the armature shaft across the frames, or parallel with the driving axles.
"On account of the high speed of the armature shaft it was not possible to connect with driving-axles direct, but this was an advantage in one way, as by introducing an intermediate counter-shaft (corresponding to the well-known type of double-reduction motor used on trolley-cars since 1885), a fairly good arrangement was obtained to regulate the speed of the locomotive, exclusive of resistance in the electric circuit.
"Endless leather belting was used to transmit the power from the motor to the counter-shaft, and from the latter to the driving-wheels, which were the front pair. A vertical idler-pulley was mounted in a frame over the belt from motor to counter-shaft, terminating in a vertical screw and hand-wheel for tightening the belt to increase speed, or the reverse to lower speed. This hand-wheel was located in the cab, where it was easily accessible....
"The rough outline sketched below shows the location of motor in relation to counter-shaft, belting, driving-wheels, idler, etc.:
"On account of both rails being used for circuits, . . . the driving-wheels had to be split circumferentially and completely insulated from the axles. This was accomplished by means of heavy wood blocks well shellacked or otherwise treated to make them water and weather proof, placed radially on the inside of the wheels, and then substantially bolted to the hubs and rims of the latter.
"The weight of the locomotive was distributed over the driving-wheels in the usual locomotive practice by means of springs and equalizers.
"The current was taken from the rims of the driving-wheels by a three-pronged collector of brass, against which flexible copper brushes were pressed--a simple manner of overcoming any inequalities of the road-bed.
"The late Mr. Charles T. Hughes was in charge of the track construction at Menlo Park.... His work was excellent throughout, and the results were highly satisfactory so far as they could possibly be with the arrangement originally planned by Mr. Edison and his assistants.
"Mr. Charles L. Clarke, one of the earliest electrical engineers employed by Mr. Edison, made a number of tests on this 1882 railroad. I believe that the engine driving the four Z generators at the power-house indicated as high as seventy horse-power at the time the locomotive was actually in service."
The electrical features of the 1882 locomotive were very similar to those of the earlier one, already described. Shunt and series field-windings were added to the motor, and the series windings could be plugged in and out of circuit as desired. The series winding was supplemented by resistance- boxes, also capable of being plugged in or out of circuit. These various electrical features are diagrammatically shown in Fig. 2, which also illustrates the connection with the generating plant.
"The principal part of the outfit was the electric motor. At that time motors were curiosities. There were no electric motors even for stationary purposes, except freaks built for experimental uses. This motor was made from the parts-- such as fields, armature, commutator, shaft and bearings, etc., of an Edison "Z," or 60-light dynamo. It was the only size of dynamo that the Edison Company had marketed at that time.... As a motor, it was wound to run at maximum speed to develop a torque equal to about fifteen horse-power with 220 volts. At the generating station at Menlo Park four Z dynamos of 110 volts were used, connected two in series, in multiple arc, giving a line voltage of 220.
"The motor was located in the front part of the locomotive, on its side, with the armature shaft across the frames, or parallel with the driving axles.
"On account of the high speed of the armature shaft it was not possible to connect with driving-axles direct, but this was an advantage in one way, as by introducing an intermediate counter-shaft (corresponding to the well-known type of double-reduction motor used on trolley-cars since 1885), a fairly good arrangement was obtained to regulate the speed of the locomotive, exclusive of resistance in the electric circuit.
"Endless leather belting was used to transmit the power from the motor to the counter-shaft, and from the latter to the driving-wheels, which were the front pair. A vertical idler-pulley was mounted in a frame over the belt from motor to counter-shaft, terminating in a vertical screw and hand-wheel for tightening the belt to increase speed, or the reverse to lower speed. This hand-wheel was located in the cab, where it was easily accessible....
"The rough outline sketched below shows the location of motor in relation to counter-shaft, belting, driving-wheels, idler, etc.:
"On account of both rails being used for circuits, . . . the driving-wheels had to be split circumferentially and completely insulated from the axles. This was accomplished by means of heavy wood blocks well shellacked or otherwise treated to make them water and weather proof, placed radially on the inside of the wheels, and then substantially bolted to the hubs and rims of the latter.
"The weight of the locomotive was distributed over the driving-wheels in the usual locomotive practice by means of springs and equalizers.
"The current was taken from the rims of the driving-wheels by a three-pronged collector of brass, against which flexible copper brushes were pressed--a simple manner of overcoming any inequalities of the road-bed.
"The late Mr. Charles T. Hughes was in charge of the track construction at Menlo Park.... His work was excellent throughout, and the results were highly satisfactory so far as they could possibly be with the arrangement originally planned by Mr. Edison and his assistants.
"Mr. Charles L. Clarke, one of the earliest electrical engineers employed by Mr. Edison, made a number of tests on this 1882 railroad. I believe that the engine driving the four Z generators at the power-house indicated as high as seventy horse-power at the time the locomotive was actually in service."
The electrical features of the 1882 locomotive were very similar to those of the earlier one, already described. Shunt and series field-windings were added to the motor, and the series windings could be plugged in and out of circuit as desired. The series winding was supplemented by resistance- boxes, also capable of being plugged in or out of circuit. These various electrical features are diagrammatically shown in Fig. 2, which also illustrates the connection with the generating plant.