Gambar halaman
PDF
ePub
[merged small][ocr errors][ocr errors][merged small][ocr errors][ocr errors][ocr errors][merged small][ocr errors][ocr errors][merged small][merged small][ocr errors][ocr errors][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][ocr errors][merged small][merged small][merged small][merged small][merged small][merged small][ocr errors][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][ocr errors][merged small][merged small][merged small]

published figures. A copy of this report was furnished to the City.

An extract from a general résumé of the subject is shown in Table XXIII.

These figures were very conservatively estimated so as to minimize any possible hostile criticism. In consequence, since electrification has actually been undertaken, the results have pleased me very much by showing a great under-estimation of savings, further accentuated by the marked increase in coal, labor and other costs during and since the War, whereas the rates of the Commonwealth Edison Company have not been increased during that period in the slightest; 1920 pumpages, of course, show about a 15 per cent increase over these figures.

The 1916 Report contained some very interesting curves, of which I append as examples those for the Chicago Avenue Station (Fig. 137) and also an aggregate curve sheet for all the stations (Fig. 138).

The City decided to electrify completely 22nd Street, 68th Street and Chicago Avenue. The 22nd Street Station is a straight leap from beam engines to electric centrifugals, as, though it has switchtrack facilities, it was due for a complete rehabilitation.

The 68th Street Station has also a switch-track, but, being in a residential neighborhood, the general complaint regarding smoke and soot was a great factor which, together with the unduly high maintenance of some steam-turbine centrifugals and the

Pumping

scrapping of some old-fashioned small-duty Holly sets, gave them the opportunity to meet the objections by electrification.

Chicago Avenue Station has no switch-track and though most of the pumping was done by modern triple-expansion sets as efficient as it is possible to make them, still the lack of coal carriage facilities, and, again, the complaint of smoke and soot, formed their decision. The triple expansion sets are now being removed to another station.

Installations made, or about to be made, are listed in Table XXIV.

The average load factor is well over 80 per cent on a 730 hours per month basis.

The Burke motors, which were the original sets installed, are synchronous, and the excess horsepower above normal pump rating is used for power factor correction.

Since, however, pump load characteristics are generally so good the later ones were specified to be of wound rotor type and give P.F.'s of near 93 per cent-which is satisfactory enough under the circumstances. It has been found that the apparent safe capacities of the centrifugals are much higher than rated, so that the motors, which were ordered on a low temperature rating, are being operated much above normal rating and well into the residual overload capacity that they possess.

Fig. 139 shows the performance curve of a 40 M.G., 1200 Hp., electric centrifugal set located at Chicago Avenue, which shows an over-all efficiency

TABLE XXIV

Centrif.

Station

[blocks in formation]
[merged small][subsumed][ocr errors][merged small][ocr errors][ocr errors][merged small][merged small][ocr errors][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][ocr errors][merged small][merged small][merged small][merged small][merged small][merged small][ocr errors][merged small][merged small][merged small][merged small][merged small][merged small][ocr errors][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small]
[merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][ocr errors][ocr errors][merged small][merged small][merged small][merged small][merged small][merged small]

Fig. 140. General External View (Water Tower in Foreground Now in Disuse) Chicago Avenue Pumping Station.

[graphic]
[graphic]

Fig. 142. Line Room and Transformer Room Chicago Avenue Pumping Station.

Fig. 143. Switchboard Gallery, Chicago Avenue Pumping Station.

of about 78 per cent, which is fairly typical of the results obtainable from most of the electric centrifugals.

Illustrations of Chicago Avenue Station, both interior and exterior, are given here, as it is thought the general beauty and treatment of it are exceptional:

(Chicago Avenue Station)

Fig. 140-General External View;

Fig. 141-Automatic Contactor Starting panels; Fig. 142-Line Room and Transformer Room (12,000 v. to 2300 v.);

Fig. 143-Switchboard Gallery-Solenoid controls.

[graphic]

and sub-meters;

Fig. 144-Two 1200 Hp., 2300 v., 3-phase, 40 M.G. Electric centrifugal units;

Fig. 145-Type of 30 M.G. triple-expansion reciprocating sets being replaced.

[merged small][merged small][merged small][graphic]

Fig. 144. Automatic Contactor Starting Panels, Chicago Avenue Pumping Station.

[graphic]

Fig. 145. Thirty M. G. Triple-Expansion Reciprocating Pumping Sets, Chicago Avenue Pumping Station.

« SebelumnyaLanjutkan »