Industrial Niagara 



besides the obvious one of having a single set of spare parts 1894 

 suffice against the breakdown of any machine in the station, is 

 that, from a point of view of the electrical aspect of the case, of 

 the machines being able all to be put in parallel, as it is called. 

 The expression may not be a familiar one to some of our readers, 

 and the following hydraulic analogy may be of service in leading 

 to an understanding of what is meant by it. Let us assume that 

 we have several pumping engines of equal power, and that we 

 are using them all to pump water from one reservoir into another 

 at a higher level. Obviously the total amount of water pumped 

 will be what a single machine handles multiplied by the number 

 of them. Had, say, one of the pumps been weaker than the 

 others — had it, that is, not been strong enough to force water 

 up to the height that the others did — the result would be that, 

 instead of doing any work when put, as we may say, in parallel 

 with the others, it would have been unable to withstand the head, 

 and water would have forced itself back through it into the lower 

 reservoir. The same way with dynamos, or generators as they 

 are usually called when referring to the machinery in a power 

 as distinct from a lighting station. The advantage of working 

 in parallel is, that if we have, say, six machines all " pumping " 

 current into the same mains and one breaks down, we may take 

 it out of circuit, and, by temporarily overloading the other five, 

 which can always be done for a short time with good machines, 

 keep on supplying full current to consumers. Should the power 

 company have decided to put in a special machine for aluminum, 

 and other special ones for other local work, and still more for 

 distant work, each would have its own circuit, and, if it broke 

 down, the whole dependent system would be idle until repairs 

 were completed. One of the great aims of the company appears 

 to be to insure the permanence and continuousness of their power 

 service — which is, of course, of the utmost importance to manu- 

 facturers. 



A remarkable method of construction — not, however, unique — 

 is employed in the generators to secure means for direct 



coupling to the turbine shafts. These latter are vertical, and 



951 



