. The Street railway journal . ments,of interest on mort-gages or bonds. In regard to the firstcost of the machinery under discussion it has been assumed that with the 500-kw unitsthe system in use will be 500 volts direct current. It is also as-sumed that the engine units will have drect-current generators,and the turbine units alternating-current generators, requiringconverting apparatus. It is further assumed that the engine willwork with saturated steam and that the turbine will use super-heated steam. We, therefore, assume the following costs for theengine unit: Per Kw Engine and generato
. The Street railway journal . ments,of interest on mort-gages or bonds. In regard to the firstcost of the machinery under discussion it has been assumed that with the 500-kw unitsthe system in use will be 500 volts direct current. It is also as-sumed that the engine units will have drect-current generators,and the turbine units alternating-current generators, requiringconverting apparatus. It is further assumed that the engine willwork with saturated steam and that the turbine will use super-heated steam. We, therefore, assume the following costs for theengine unit: Per Kw Engine and generator $ Condensing apparatus : Foundations On the same basis we assume that the turbine with saturatedsteam would cost as follows: Per Kw Turbine and generator $ Condensing apparatus Foundation Motor generator apparatus and switchboard Engine and apparatusFoundations Total On the same basis as the above we have turbine and generator . Foundations Superheater and piping Total. Per Cent Hating GRAPHIC COMPARISON OF TUR1UXE AND ENGINE COSTS total ..03 In order, however, that full operating value from the stand-point of steam economy may be obtained from the turbine, it isnecessary to install with our boilers some superheaters, and forthis additional cost we should apply $ per kw, making agrand total for the turbine of $ In order to show the effect upon the combined kw-hour cost ofhaving to add converting apparatus, curve D in Fig. 1 hasbeen made, based on a total first cost of $69,25, less $ For 1500 kw-units it has been assumed that both the engine-driven and turbine-driven unit will generate alternating current,and on this basis there have been assumed the following costs: In the case of curves for 1500-kw units, it has been assumed,without question, that the engine will run with saturated steamand the turbine with superheated steam. On the basis of all-sized units, operating alternating current,the 500-kw turbin
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectstreetr, bookyear1884
