The First Edison Central Station- 7

The First Edison Central Station- 7

 Everything worked satisfactorily in the main. There were a few mechanical and

engineering annoyances that might naturally be expected to arise in a new and

unprecedented enterprise; but nothing of sufficient moment to interfere with the steady

and continuous supply of current to customers at all hours of the day and night. Indeed,

once started, this station was operated uninterruptedly for eight years with only

insignificant stoppage.

It will have been noted by the reader that there was nothing to indicate rashness in

starting up the station, as only one dynamo was put in operation. Within a short time,

however, it was deemed desirable to supply the underground network with more current,

as many additional customers had been connected and the demand for the new light was

increasing very rapidly. Although Edison had successfully operated several dynamos in

multiple arc two years before--i.e., all feeding current together into the same circuits--

there was not, at this early period of experience, any absolute certainty as to what

particular results might occur upon the throwing of the current from two or more such

massive dynamos into a great distributing system. The sequel showed the value of

Edison's cautious method in starting the station by operating only a single unit at first.

He decided that it would be wise to make the trial operation of a second "Jumbo" on a

Sunday, when business houses were closed in the district, thus obviating any danger of

false impressions in the public mind in the event of any extraordinary manifestations. The

circumstances attending the adding of a second dynamo are thus humorously described

by Edison: "My heart was in my mouth at first, but everything worked all right.... Then

we started another engine and threw them in parallel. Of all the circuses since Adam was

born, we had the worst then! One engine would stop, and the other would run up to about

a thousand revolutions, and then they would see-saw. The trouble was with the

governors. When the circus commenced, the gang that was standing around ran out

precipitately, and I guess some of them kept running for a block or two. I grabbed the

throttle of one engine, and E. H. Johnson, who was the only one present to keep his wits,

caught hold of the other, and we shut them off." One of the "gang" that ran, but, in this

case, only to the end of the room, afterward said: "At the time it was a terrifying

experience, as I didn't know what was going to happen. The engines and dynamos made a

horrible racket, from loud and deep groans to a hideous shriek, and the place seemed to

be filled with sparks and flames of all colors. It was as if the gates of the infernal regions

had been suddenly opened."

This trouble was at once attacked by Edison in his characteristic and strenuous way. The

above experiment took place between three and four o'clock on a Sunday afternoon, and

within a few hours he had gathered his superintendent and men of the machine- works

and had them at work on a shafting device that he thought would remedy the trouble. He

says: "Of course, I discovered that what had happened was that one set was running the

other as a motor. I then put up a long shaft, connecting all the governors together, and

thought this would certainly cure the trouble; but it didn't. The torsion of the shaft was so

great that one governor still managed to get ahead of the others. Well, it was a serious

state of things, and I worried over it a lot. Finally I went down to Goerck Street and got a

piece of shafting and a tube in which it fitted. I twisted the shafting one way and the tube

the other as far as I could, and pinned them together. In this way, by straining the whole

outfit up to its elastic limit in opposite directions, the torsion was practically eliminated,

and after that the governors ran together all right."

Edison realized, however, that in commercial practice this was only a temporary

expedient, and that a satisfactory permanence of results could only be attained with more

perfect engines that could be depended upon for close and simple regulation. The engines

that were made part of the first three "Jum- bos" placed in the station were the very best

that could be obtained at the time, and even then had been specially designed and built

for the purpose. Once more quoting Edison on this subject: "About that time" (when he

was trying to run several dynamos in parallel in the Pearl Street station) "I got hold of

Gardiner C. Sims, and he undertook to build an engine to run at three hundred and fifty

revolutions and give one hundred and seventy-five horse-power. He went back to

Providence and set to work, and brought the engine back with him to the shop. It worked

only a few minutes when it busted. That man sat around that shop and slept in it for three

weeks, until he got his engine right and made it work the way he wanted it to. When he

reached this period I gave orders for the engine-works to run night and day until we got

enough engines, and when all was ready we started the engines. Then everything worked

all right.... One of these engines that Sims built ran twenty-four hours a day, three

hundred and sixty-five days in the year, for over a year before it stopped."[12]

[12] We quote the following interesting notes of Mr. Charles L. Clarke on the question of

see-sawing, or "hunting," as it was afterward termed:

"In the Holborn Viaduct station the difficulty of `hunting' was not experienced. At the

time the `Jumbos' were first operated in multiple arc, April 8, 1882, one machine was

driven by a Porter-Allen engine, and the other by an Armington & Sims engine, and both

machines were on a solid foundation. At the station at Milan, Italy, the first `Jumbos'

operated in multiple arc were driven by Porter-Allen engines, and dash-pots were applied

to the governors. These machines were also upon a solid foundation, and no trouble was

experienced.

"At the Pearl Street station, however, the machines were sup- ported upon long iron

floor-beams, and at the high speed of 350 revolutions per minute, considerable vertical

vibration was given to the engines. And the writer is inclined to the opinion that this

vibration, acting in the same direction as the action of gravitation, which was one of the

two controlling forces in the operation of the Porter-Allen governor, was the primary

cause of the `hunting.' In the Armington & Sims engine the controlling forces in the

operation of the governor were the centrifugal force of revolving weights, and the

opposing force of compressed springs, and neither the action of gravitation nor the

vertical vibrations of the engine could have any sensible effect upon the governor,"