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December, 1909 . frequency I have forgotten the volt- age proposed on the combination drive, but I think it was about 2,000, and on the other 2,300; in both cases the frequency at the maximum is ap- proximately 60 cycles. The reason for the adoption of a voltage of 2,300 is on account of the convenience in the switches and windings. If you use a lower voltage the change of con- nections becomes very heavy, and you must use big switches to handle them, but in this case it is simpler to use such voltage as I have stated, because it is simple both for the induction mo- tor and the generator. What we have done is to compare carefully the num- ber of factors in both, and arranged and tested one and the other, until we got the best plans and got the best condi- the generator and induction That 'ives a <switch at. 4500 amperes. We use a switch with big toggle brushes, brushes made of that shape (illustrating on the blackboard) that are bushed in to make an insulat- ing handle. This is a mica insulator here, this is all insulation, here is the toggle. A toggle of small size applies great pressure to this switch, and it makes a method of conduction just ex- actly: as (good as if}: thé 'bars. were soldered up and riveted perfectly. It is not a switch suitable to open under load, but is absolutely positive in its closing. President Taylor: Mr. Emmet's pa- per has certainly given you all food for thought, and whether you all agree with him in his conclusions or not, there will be a great benefit accrue to our industry from the reading of it. tions in motor. Weights a Surprise. Mr. Emmet: Mr. President, there is one more remark I desire to make. The question of weight has been em- phasized, and I want to speak about that. The weights have been a surprise to me. The apparatus is designed with a view to keeping it light, although the mechanical construction of the turbine is just such as we would use and are using actually in the land service. We have made recently within a few days a very large proposition. The turbine on which we made that proposition was almost identically the same as this, same speed and same capacity. It is outside of the country, but we expect to close the contract for it. The actual calculat- ed weight on that and this are identical, the same number of stages, speed, etc. The weight of generators and motors and all such things are questions 0} ventilation, carrying away the heat, and that is a very important problem in con- -overload. TAE Marine Review nection with this application tricity, which ought to have been touchea on in this paper more fully. The prop- osition in this case is 0 "put an & special additional connection for air, taking air down from ventilators and leading it directly to the apparatus then supplying to your generator motor blowers, air-impelling devices which will force a large amount of outdoor air through them. The fact that we are using out-door air is in our favor. In fact, we use a large. amount, and it enables us to make the apparatus somewhat smaller. The thermal con- ditions are not any worse aboard ship than they are in many existing instai- lations that are successful. That has been one of the points of special de- sign, by which we gain in weight. and and No Claim of Novelty. Another thing which should be cited is this--that this apparatus is designed on a peak load basis, this high-speea condition of a battleship corresponds to the occasional extreme peak on some electrical plants on land, and this tur- bine gives these conditions. The tur- bine which I have described in my paper is run at what we consider a heavy That turbine, instead of be- ing rated at 11,000 kw., would ordinarily be rated approximately at 8,000 kw., and this is an overload condition, but it is an overload condition which the turbine can. stand indefinitely, with a considerable temperature rise and a large amount of air passing through. Those conditions, all of them, are entirely safe. The distributive character of the wind- ing is such that the whole mass of the apparatus will heat up together, and there will be no local heating of parts which will endanger the ship at all. Of course, it has been said that I claim thing. I do not. I tried to disclaim it in the beginning of the paper. There is nothing in this paper which is not a matter of general knowl- edge as far as principle is concerned. I have made a few possible inventions in connection with these combinations which may or may not be new. The whole thing is the skill with which it is designed and worked out, and I claim that these are actual designs, and that they are right, and I think that they are right, and the only novelty I elaim is that I have taken the trouble to work out real designs, whereas, others have discussed generalities and in discussing weights as generalities you are apt to mislead yourselves and put in something which seems to be an operative condi- tion or which turns you away from it, novelty in this of elec- : 497 and that is generally not the limitation ate all, The Problem of Resistance. One of the important points considered in this paper is the question of 'resist- ance. One of the great problems in getting torque out of a large motor is to dispose of the energy. When an induction motor stands still it acts simply as a transformer. Its primary and secondary are stationary to each other, and any current you put into it is transferred directly from one to the other. If it is to produce any torque and do any work, it must be dissipatea in the secondary. If we simply allow current to go in without absorbing it by resistance, the current simply dissi- pates itself and no work is done, and you are simply magnetizing current and the total loss is the heating due to the hysteresis of the iron and the heating of the conductors. To get torque, we must have work done, and this work must be thrown away. The only prac- tical way of dissipating so large an amount of energy, which is virtually the whole output of the generator, is to put it into water and throw the water away, nothing will use up the heat faster. If we had to cool the. resistance by pumping air we would have the cold air apparatus ten times as os as the other apparatus. When I first considered this question, I saw that this resistance business be- came a large proposition, and I turned away from it at first on that account, but I have since made a resistance and I have dissipated energy into small spaces on quite a large scale, and know exactly what I can do. New Metal Talorite. I will show you what that device is. (Drawing on blackboard.) This is a U made of drain tile pipe. One of our engineers about two years ago developed a kind of metal which we call talorite, which is a metal we use for resist- ances. It has the peculiarity of having a very high resistance, a very constant resistance, about 65 times that of cop- per. It also has the peculiarity of being entirely non-corrosive. A small piece, the size of a cambric needle, ex- posed in a sal- ammoniac solution to- gether with the cambric needle showed no sign, 'of diminution in weight, where- as the needle was entirely gone. Further- more, it is almost proof against electro-. lysis, and it occurred to me, therefore, that this was something we could use in water resistance, because the trouble with water resistances is that they de- stroy themselves and there is a large