discussion on mr. lyndon's paper

2
732 DISCUSSION AT NEW YORK. LNov. 20 DISCUSSION ON MR. LYNDON'S PAPER. J. R. APPLETON':-.The value of a battery for relieving the strain on the generators with fluctuating loads is well illustrated by a plant at Oakland, California. The station equipment com- prises one 600- and one 850-kilowatt generator; without the battery it was essential to keep a man at the throttle of each engine, on account of the rapid variations of load; with the bat- tery, the 850-kilowatt generator maintains the load between 700 and 800 amperes continually, and the battery supplies current up to 2,600 amperes; that is, a constant load is kept on one generator, and the other generator becomes a spare unit. J. L. WOODBRIDGE:-It may be worth while to point out that the function of a battery at the station is different from that at the end of a feeder. The station battery will keep the station load constant and regulate the station voltage; the feeder bat- tery will not hold the station voltage constant to any material extent, and will not reduce the load fluctuations materially. W. E. GOLDSBOROUGH:-The introduction of a storage-battery at a center of distribution of the St. Louis Rapid Transit Com- pany's system has made a saving in copper which pays for the installation of the battery and all the auxiliary machinery used in connection with it. J. W. LIEB:-Though not immediately germane to the paper, it may be worth while to point out the very great import- ance of a storage-battery in a large alternating current generating station to supply field excitation. It is imperative that batteries should be installed for this purpose which may be thrown in- stantly on the field circuit to take the place of the other exciters; for this purpose, the battery capacity should be large. The speaker has made a test on a large plant with several 4500 kw. alternators in parallel, throwing out the motor-generator ex- citers and throwing the whole exciter equipment on the battery; there were practically no fluctuations in the bus-bar voltage. In the speaker's opinion, it is also imperative that thestorage- battery should be used as a reserve in any general direct-current distribution system supplying a large population and obtaining etrrent from a high-pressure transmissoin plant, the possible causes of interruption to service are so nurmerous that such a sys- tem cannot be considered safe without a very large reserve in battery. W. W. DONALDSON:-A battery on a line should be installed so that the greatest possible amount of work will be done by the battery if it discharges only once a day, it is not doing as much work as it should. This question of amount of use durilng the day should be given consideration. W. E. GOLDSBOROUGH:-A battery should unquestionably be adjusted to give the maximum return to the equipment with which it is connected. A battery supplies a means for keeping all the apparatus working at the point of maximum efficiency, from the central station, through the sub-stations, and on to the

Upload: j-r

Post on 16-Mar-2017

215 views

Category:

Documents


1 download

TRANSCRIPT

Page 1: Discussion on Mr. Lyndon's Paper

732 DISCUSSION AT NEW YORK. LNov. 20

DISCUSSION ON MR. LYNDON'S PAPER.J. R. APPLETON':-.The value of a battery for relieving the

strain on the generators with fluctuating loads is well illustratedby a plant at Oakland, California. The station equipment com-prises one 600- and one 850-kilowatt generator; without thebattery it was essential to keep a man at the throttle of eachengine, on account of the rapid variations of load; with the bat-tery, the 850-kilowatt generator maintains the load between 700and 800 amperes continually, and the battery supplies currentup to 2,600 amperes; that is, a constant load is kept on onegenerator, and the other generator becomes a spare unit.

J. L. WOODBRIDGE:-It may be worth while to point out thatthe function of a battery at the station is different from thatat the end of a feeder. The station battery will keep the stationload constant and regulate the station voltage; the feeder bat-tery will not hold the station voltage constant to any materialextent, and will not reduce the load fluctuations materially.W. E. GOLDSBOROUGH:-The introduction of a storage-battery

at a center of distribution of the St. Louis Rapid Transit Com-pany's system has made a saving in copper which pays for theinstallation of the battery and all the auxiliary machinery usedin connection with it.

J. W. LIEB:-Though not immediately germane to thepaper, it may be worth while to point out the very great import-ance of a storage-battery in a large alternating current generatingstation to supply field excitation. It is imperative that batteriesshould be installed for this purpose which may be thrown in-stantly on the field circuit to take the place of the other exciters;for this purpose, the battery capacity should be large. Thespeaker has made a test on a large plant with several 4500 kw.alternators in parallel, throwing out the motor-generator ex-citers and throwing the whole exciter equipment on the battery;there were practically no fluctuations in the bus-bar voltage.In the speaker's opinion, it is also imperative that thestorage-battery should be used as a reserve in any general direct-currentdistribution system supplying a large population and obtainingetrrent from a high-pressure transmissoin plant, the possiblecauses of interruption to service are so nurmerous that such a sys-tem cannot be considered safe without a very large reserve inbattery.W. W. DONALDSON:-A battery on a line should be installed

so that the greatest possible amount of work will be done by thebattery if it discharges only once a day, it is not doing as muchwork as it should. This question of amount of use durilng theday should be given consideration.W. E. GOLDSBOROUGH:-A battery should unquestionably be

adjusted to give the maximum return to the equipment withwhich it is connected. A battery supplies a means for keepingall the apparatus working at the point of maximum efficiency,from the central station, through the sub-stations, and on to the

Page 2: Discussion on Mr. Lyndon's Paper

1903.] BRANCH DISCUSSIONS. 733

line. In a large system, the small loss of energy in the battery isunimportant in comparison with the reduction of depreciation-which it brings about in all other parts of the system.

A. S. HUBBARD:-In a railway power-station, the averageload is not the same at different periods of the day. A booster,should be capable of adjustment to change the average loadsupplied by the generator. If a battery is proportioned for thedaily average, it will be far larger than necessary to care for themomentary peaks; by proportioning the booster so that theaverage load, as represented by the generator load, can be raisedor lowered, as conditions demand, the size of the battery maybe reduced. A similar consideration applies to the floating bat--tery when the car schedule is changed; but on a system using aconstant-current booster in a power-station with a separatefeeder to the battery, a change of schedule can be cared for bychanging the booster output. Further, if a battery is operated;on a daily average, its efficiency is far less than if operated forcomparatively short periods-say, of two or three hours.LAMAR LYNDON:-The various points presented by the differ-

ent speakers, while interesting, do not seem to be directly ger-mane to the paper in hand. There is therefore nothing to be*added to the statements of the paper.

BRANCH DISCUSSION.DiscussioN ON MR. LYNDON'S PAPER AT PITTSBURG, DECEMBER

3, 1903.F. L. FLANDERS :--Mr. Lyndon says that a battery should not

be worked above its one hour rating, and even then only for-moderate periods. This rating was established by the largestbattery company because its cells cannot be used safely atgreater rates. Batterie§ of the Plante type, made in Germany,do, however, work at much higher rates. The following testwas made on a cell of this type, having a capacity of 1000 am--pere-hours at the eight-hour rate: the cell was discharged at4000 amperes for 30 seconds; then allowed to rest for 20 sec-onds; then discharged at from 400 to 500 amperes for five min--utes; then allowed to rest for 10 seconds. This completed acycle, which was immediately repeated. This test was con--tinued day and night for six days of the week, ior two and one--half years, and at the conclusion, no depreciation of the cellwas to be seen. In Germany it is customary to work at muchhigher discharge rates than in the United States, but only forshort periods.The 200-ampere Edison cell is now on the market. For the

same power, this cell occupies 17%70 more space than a lead cell,'but for the same weight it gives 40%70 greater output. Thepressure of the Edison cell at discharge is 1.3 volts at first,falls rapidly to 1.25 volts, and after reaching 1.1 volt dropsin about 15 minutes, to 0.7 volts, and five minutes after falls