April i, 1901.] 



THE INDIA RUBBER V/ORLD 



201 



THE ELECTRIC DRIVING OF RUBBER MILLS. 



By J. O. De Wolf. 



THE last years of the past century have been so full of 

 changes that affect our modes of living, carrying on 

 business, and manufacturing, that forces which for 

 centuries had lain dormant, or only rendered usa small 

 part of their possible power, are now so commonly used that 

 we give them but little thought. The horse, as a motive power 

 for street cars, is almost a thing of the past, and of such rare 

 occurrence that it attracts more than passing attention, while 

 the advantages of electricity for street car propulsion are so 

 obvious that one does not require to be an engineer to appreci- 

 ate them. We all remember well the difficulty with which the 

 old time cars climbed the hills of our cities, even with the as- 

 sistance of an extra horse, and how, when the tracks were ob- 

 structed by snow, they made slow progress, even with four 

 horses instead of two. Contrast this 

 with the ease with which the elec- 

 tric cars climb hills — even those too 

 steep to be attempted the old way 

 — and through snow blockades ; also 

 the perfect control which the mo- 

 torman has of his car, not only in 

 starting and stopping, but also in 

 varying the speed. 



A part of the vast power that for 

 ages has plunged unused over the 

 Niagara falls now generates elec- 

 tricity that is carried to factories 

 miles away, and there furnishes them 

 with their motive power. Such a 

 transformation of energy from the 

 point where it is found to any point 

 where it is desired for use, com- 

 mends itself at once to the observer, 

 and suggests changes in the meth- 

 ods of driving factories no less 

 radical than those wrought during 

 the last fifteen years on street rail- 

 ways. As the electric method of 

 driving is already in such successful 

 practical operation in factories of 

 different kinds, it is fitting here to 



consider its application to rubber mills, and note the great 

 advantages possessed by this modern method over the meth- 

 ods previously used. 



Starting in the engine room of almost any rubber plant, we 

 find a large and comparatively slow speed engine driving the 

 mill room through a set of gears or by a rope drive. As the 

 main shaft in the mill and calender room runs about 50 to 60 

 revolutions per minute, it is necessary to reduce this speed ma- 

 terially from that of the engine itself. The slow speed and 

 large power required in this part of the plant make necessary 

 large and heavy gearing, or wide and large pulleys. The loss 

 of power through this drive or gearing is also a constant drain 

 on the coal pile, but not the only one, for the long line of heavy 

 shafting at about the floor level uses up at its best a valuable 

 and considerable amount of power, and any settling in the bear- 

 ings, that is sure to occur, adds greatly to this friction loss. 



What rubber superintendent does not remember hours of 



MOTOR DRIVING OVERHEAD SHAFTING, 



connecting his mill room shafting with his engine, and the time 

 spent in aligning this shaft, although not until many horse 

 power had been lost for days or weeks. Then, coming to the 

 mills and calenders, we find them running at one or two fixed 

 speeds with no means of changing the speed. Now turn to a 

 similar plant, electrically equipped. In place of the large belts 

 ropes or shafting, and gearing to carry the power, we find wires 

 running to any part of the plant where power is desired. In 

 the mill room the mixers and warming up mills are grouped 

 together and several driven by one motor. The friction of a 

 large gear or belt drive is entirely saved, and also the friction, 

 of the long line of main shafting. The saving in the cost of 

 these items and the necessary foundations for them is a point 

 to be carefully noted. Whenever it is desired to shut down a 

 group of these mixers, the motor is 

 stopped, and no power is used by 

 them. There is also a saving of all 

 that friction lost in driving the 

 whole of a large main shaft when it 

 is only desired to run a few mills. 



The calender having its own mo- 

 tor, can be run as a street car is run, 

 and instead of using the nearest 

 proper speed that can be got out of 

 perhaps two combinations, you have 

 unlimited control and speed your 

 calender rolls to suit the stock you 

 are running, making a great saving 

 not only in production, but also in 

 perfection of work. 



When the question of an addition 

 to a plant comes up, where the elec- 

 tric drive is used, you are not tied 

 • down as in the old systems, and it is 

 not necessary to continue the mill 

 room in line with the old one or 

 figure how to take more power from 

 an already overloaded shaft. Nor 

 is it necessary, when first installed, 

 to use a larger shaft than necessary 

 in order to allow for future exten- 

 sion. The extension of a few wires and the installation of new 

 motors gives power whenever required. 



It is not within the scope of this article to go fully into the 

 application and merits of the electric drive, but it must not 

 close without reference to that important feature, the central- 

 izing of power plants. In all large and growing factories 

 power has to be carried to remote parts, and in many cases this 

 has resulted in the installation of separate engines, and per- 

 haps even new and separate boiler plants to run them. Such 

 divisions of a power plant not only render its running more 

 expensive, by reason of the increased force of engineers and fire- 

 men, but also on account of the decreased efficiency of small 

 engines. If it is attempted to carry the power mechanically for 

 a long distance there is of necessity a considerable loss in fric- 

 tion, and where belting or ropes are used a variation in speed 

 due to the slip under different atmospheric conditions. 

 By the use of the electric drive the entire power plant can be 



shutdowns or night work in repairing the drivingarrangements centralized at the most convenient point, and large and econ- 



