The First Edison Central Station- 9

The First Edison Central Station- 9

 "To the Editor of the Sun:

"SIR,--In reading the discussions relative to the Pearl Street station of the Edison light, I

have noted that while it is claimed that there is scarcely any loss from leakage of current,

nothing is said about the loss due to the resistance of the long circuits. I am informed that

this is the secret of the failure to produce with the power in position a sufficient amount

of current to run all the lamps that have been put up, and that while six, and even seven,

lights to the horse-power may be produced from an isolated plant, the resistance of the

long underground wires reduces this result in the above case to less than three lights to

the horse-power, thus making the cost of production greatly in excess of gas. Can the

Edison company explain this?

"INVESTIGATOR."

This was one of the many anonymous letters that had been written to the newspapers on

the subject, and the following reply by the Edison company was printed December 3,

1882:

"To the Editor of the Sun:

"SIR,--`Investigator' in Wednesday's Sun, says that the Edison company is troubled at its

Pearl Street station with a `loss of current, due to the resistance of the long circuits'; also

that, whereas Edison gets `six or even seven lights to the horse-power in isolated plants,

the resistance of the long underground wires reduces that result in the Pearl Street station

to less than three lights to the horse-power.' Both of these statements are false. As regards

loss due to resistance, there is a well-known law for determining it, based on Ohm's law.

By use of that law we knew in advance, that is to say, when the original plans for the

station were drawn, just what this loss would be, precisely the same as a mechanical

engineer when constructing a mill with long lines of shafting can forecast the loss of

power due to friction. The practical result in the Pearl Street station has fully

demonstrated the correctness of our estimate thus made in advance. As regards our

getting only three lights per horse-power, our station has now been running three months,

without stopping a moment, day or night, and we invariably get over six lamps per horsepower,

or substantially the same as we do in our isolated plants. We are now lighting one

hundred and ninety-three buildings, wired for forty-four hundred lamps, of which about

two-thirds are in constant use, and we are adding additional houses and lamps daily.

These figures can be verified at the office of the Board of Underwriters, where

certificates with full details permitting the use of our light are filed by their own

inspector. To light these lamps we run from one to three dynamos, according to the lamps

in use at any given time, and we shall start additional dynamos as fast as we can connect

more buildings. Neither as regards the loss due to resistance, nor as regards the number of

lamps per horse-power, is there the slightest trouble or disappointment on the part of our

company, and your correspondent is entirely in error is assuming that there is. Let me

suggest that if `Investigator' really wishes to investigate, and is competent and willing to

learn the exact facts, he can do so at this office, where there is no mystery of

concealment, but, on the contrary, a strong desire to communicate facts to intelligent

inquirers. Such a method of investigating must certainly be more satisfactory to one

honestly seeking knowledge than that of first assuming an error as the basis of a question,

and then demanding an explanation.

"Yours very truly,

"S. B. EATON, President."

Viewed from the standpoint of over twenty-seven years later, the wisdom and necessity

of answering anonymous newspaper letters of this kind might be deemed questionable,

but it must be remembered that, although the Pearl Street station was working

successfully, and Edison's comprehensive plans were abundantly vindicated, the

enterprise was absolutely new and only just stepping on the very threshold of commercial

exploitation. To enter in and possess the land required the confidence of capital and the

general public. Hence it was necessary to maintain a constant vigilance to defeat the

insidious attacks of carping critics and others who would attempt to injure the Edison

system by misleading statements.

It will be interesting to the modern electrician to note that when this pioneer station was

started, and in fact for some little time afterward, there was not a single electrical

instrument in the whole station-- not a voltmeter or an ammeter! Nor was there a central

switchboard! Each dynamo had its own individual control switch. The feeder connections

were all at the front of the building, and the general voltage control apparatus was on the

floor above. An automatic pressure indicator had been devised and put in connection with

the main circuits. It consisted, generally speaking, of an electromagnet with relays

connecting with a red and a blue lamp. When the electrical pressure was normal, neither

lamp was lighted; but if the electromotive force rose above a predetermined amount by

one or two volts, the red lamp lighted up, and the attendant at the hand-wheel of the field

regulator inserted resistance in the field circuit, whereas, if the blue lamp lighted,

resistance was cut out until the pressure was raised to normal. Later on this primitive

indicator was supplanted by the "Bradley Bridge," a crude form of the "Howell" pressure

indicators, which were subsequently used for many years in the Edison stations.

Much could be added to make a complete pictorial description of the historic Pearl Street

station, but it is not within the scope of this narrative to enter into diffuse technical

details, interesting as they may be to many persons. We cannot close this chapter,

however, without mention of the fate of the Pearl Street station, which continued in

successful commercial operation until January 2, 1890, when it was partially destroyed

by fire. All the "Jumbos" were ruined, excepting No. 9, which is still a venerated relic in

the possession of the New York Edison Company. Luckily, the boilers were unharmed.

Belt- driven generators and engines were speedily installed, and the station was again in

operation in a few days. The uninjured "Jumbo," No. 9, again continued to perform its

duty. But in the words of Mr. Charles L. Clarke, "the glory of the old Pearl Street station,

unique in bearing the impress of Mr. Edison's personality, and, as it were, constructed

with his own hands, disappeared in the flame and smoke of that Thursday morning fire."