[X001M2AN], Letter from Wilson Stout Howell to Samuel A Crozer, Jr., Edison Electric Light and Power Co (St Paul), December 1st, 1888
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[X001M2AN], Letter from Wilson Stout Howell to Samuel A Crozer, Jr., Edison Electric Light and Power Co (St Paul), December 1st, 1888
Dear Sir: I hereby present for your consideration the following report of the of the inspection of your plant at St. Paul. The main object of which is to make know to you the present condition of the plant from the department to the lamps, its faults and their remedies. Concurring the motive power I have nothing to report not being competent to treat upon such subject. I shall therefore begin with the dynamos and end with the light. ## The twelve #20 dynamos are in excellent condition so far as their appearance indicates. The only fault apparent being that some commutation are worn down so that the bars are too think to carry current without excessive heating. All commutations are kept clean and smooth and are much better than [xxx blurred out] average. In #20 dynamos is built for 400 amperes at 125 volts and any increase of either the current or the pressure means an overload. Your [xxx] load is a little over 2000 amperes on each "side" of the three wire system. To carry this load you employ five pairs of dynamos, five dynamos on each "side", each dynamos carrying, for about an hour each day, 400 amperes at 145 volts, which is an overload of 16% or equivalent to a load of 464 amperes at 125 volts. An overload of this character is in some respects worse than an ordinary overload of current at a pressure of 125 volts or lower because the magnets of the dynamos are much stronger with the higher voltage and the Foucault currents set up in the iron core of the armature not only take additional power but cause much extra heating which is injurious to the insulation of the armature conductors. In view of these facts it would be wire to run six pairs of dynamos during your heaviest load, provided that you have plenty of stance, for them all the dynamos would be running a trifle below their capacity and the armatures would be much less liable to injury. The reason for such an excess pressure at the dynamos is that the feeders are too small to deliver the maximum load of the station to the mains at 110 volts unless the station pressure is increased to 145 volts. When your load is light, as on Sundays, it requires only 115 volts pressure on the dynamos to deliver 330 amperes to the mains at 110 volts a loss of 5%. As the load increases so is it necessary to increase the pressure at the dynamos to keep up their pressure on the mains at the feeder ends, until with a load of 2000 amperes or more (on each side) we find a pressure of 145 volts, or more on the dynamos. Your pressure at the ends of the feeders where they join the mains is 110 volts when indicators are on zero and the difference between the dynamos pressure and the pressure at the ends of the feeders were calculated for 15% loss, and that the original plan was for 15 feeders of these 15 feeders right are in use with a loss verying from 5% with only 330 amperes to 24% with 2000 amperes output. According to your engines daily reports your average load is 750 amperes on each side the dynamos pressure is 132 volts and the loss is 16% therefore it is safe to assume that your average loss is at least 16% or higher than the maximum loss was intended to be with 15 feeders. A reduction of this loss means a reduction of your coal bills nearly in proportion and a reduction of wear and tear on dynamos engines and belts. If your loss at full load is reduced to 15% your dynamos pressure would be about 130 volts and the saving would be 10% of the fuel which if coal costs 2000 per mouth would be a saving of $200 per month in fuel alone. A reduction of this loss can be made in two ways, first by increasing the size of the present feeders or by adding other feeders as on original plan, second by using the new type high economy Edison lamp only which as it requires but two thirds as much current as the old type lamp would reduce your maximum current from 2000 amperes on each side to about 1350 amperes and your dynamos pressure to about 135 volts under which conditions your loss on finders at full load would be about 18% or an average loss of about 12% without any allowance for increase of consumers. The wisest plan would be to add feeders to those districts where load is heavy and at same time change as many consumers lamps to the new type high economy lamp as is practicable. The new feeders would make an immediate betterment of the light in their locality and at once reduced the station pressure while the substitution of the high economy lamp would make a gradual reduction of load on the station, better the light all around and reduce the station pressure still farther. In changing to the new lamps [diagrams and calculations] I would advise that where the pressure is now good, as in the district West of Cidar St. the new lamps should be of 106 volts and that as soon as the new feeders are working that the same lamps be used for all consumers. As your station load decreases with substitution of new lamps for old decreases with subsitution of new lamps for old you will find that lamps of 107 volts will give you excellent results both in illumination and in life provided that your regulation is faithfully performed so that a constant pressure of 110 volts is maintained on mains at ends of feeders. With such regulation the life of the lamps will exceed the life of the lamps now in use, the lamps will blacken much less and the light will be practically constant and uniform and of a better color. This change would remove the cause of the majority of complaints but not of all. Many complaints of poor light arise from blackened lamps. Lamps blacken because of too high pressure a pressure of 110 volts is too high for lamps of 102 and 103 volts and will cause excessive breakage and blackening and also a deterioration of the carbon fillment which will cause it to give less light. An overstarained carbon in a blackened globe affords a missonable illumination. You have a large number of blackened lamps at St. Paul. They become blackened during your light loads where the pressure is at 109 to 110 on all mains. When your station started in 1887 you had a light load for the feeders and then the lamps much have been burned very high, at least 22 to 24 candles power on a 16 candle lamp, this accounts for the statements of consumers who say that the light was elegent last year, yet those very consumers had at the time of such complaint a pressure which would give them over 20 candles from a 16 candle lamps this accounts for the statements of consumers who say that they light was elegent last year, yet those very consumers had at the time of such complaint a pressure which would give them over 20 candles from a 16 candle lamps if the lamp were not blackened. This is on the assumption that your pressure has been held as 110 volts. If the pressure has not been carefully regulated it is safe to say that it has often been much higher than 110 especially on light loads, in which case greater injury has been done to the lamps. Constant pressure is most desirable and can only be attained by having a boy or man on duty to operate the regulators and equalize during changing loads. Such a man can save many times his cost by decreasing lamp breakage and blacking and maintaining constancy of light. The question of blackened or dull lamps (overstrained lamps) is often a serious and puzzling one to station managers. When a lamp is burned out you know what to do with it but when a lamp becomes so discolored as to cutdown its light 25. 30 or 50% the consumer (especially if he pays 90 cents for his renewals of lamps) and the manager are often puzzled to know just what is to be done. Lamps blacken from two causes overburning, or abnormally high pressure and exteme long life at a proper incandescence. If the lamp has been strained whose fault is it? If the contract has been abused by the consumer and lamps burned all day and all night on a nine oclock contract is the consumer entitled to any rebate or consideration? If lamps have been burned at a proper pressure and blacking is caused by exceeding long life the consumer should be made aware that his lamps have outlived their usefulness and should be repalced by new ones at his expense or he should be less critical if too mean to study his own interests. Your trouble form this cause comes mainly under the first two heads the necessary action is plain on the second case. In the first I would make as good a compromise as possible. Offer to replace such lamps as you know to be useless from discoloration and overburning at half price by private and special agreement with such consumers as ou have confidence in or throw of 25 or 30% in more doubtful cases and replace all such lamps with high economy lamps of 106 or 107 volts. By this exchange you will accomplish two coveted objects a betterment of the light and a reduction of the laod in proportion to the number of the high economy lamps given out. The new high economy lamps of 106 volts will give a better light (clearer and more of it) than the discolored or over strained lamps of 102 volts, but not so much light as a new lamp of 102 volts of the old type so that it is not wise to mix the new lamps. Give out only one type of new lamps to each customer or some observing consumer will want an explanation which will not be convenient to give off hand as to why two lamps marked 16 have difference size carbons and give such a different light. The lamps which you have now in stock marked 16 102 volts when first used on your circuits with from 108 to 110 volts pressure will give a light of about 20 to ex candle. This is the light which you have been selling as 16 candle power, you have raised the standard of a 16 candle lamps so that people have a false idea of its value, an exagerated estimate of its illuminating power, so that when you give your suctomers a square 16 or 18 candles powerfrom a 16 candle lamp it must not be compared to a bright, clean, new 16 candle lamps of 102 volts which is giving, say 22 candle power of light, unless your power of persusasion and ready wit are equal to the issue which is sure to arise. In a meter system you can give a customer any size lamps he wants and if the 16 is too small load him up with 20's and 24's only taking care to give meter customers lamps of one type only but them all be of the old type or of the new type, but do not mix old and new type lamps in same store if on meter. Many complaints of light arise from comparison of Edison light with arc light. The arc light being of a clear, intense dazzling white, raises the standard of light and by comparason the incandiscence light appears rid or yellow. In many stores where complaints were made of poor light. I found the pressure high (108 to 109 volts on lamps of 102 volts) and lamps giving fully 30% more light than they were built for yet the effect of the light was poor by comparison with arc lamps burning close to show windows over the pavement. The whiter color of the new type lamp will lessen the bad effects of the comparison between arc and incandescence light but will not entirely satisfy those who persist in using both arc and incandescence lamps. Another way in which the load on the statoin can be reduced is by the use of meters to measure the current served to customers. The effect of meters is to prevent wastefullness on part of consumer and cut down the laod at all its stages especially during daylight and after midnight. Besides cutting down the load meters reduce the hours of burning thereby preventing much of the trouble caused by blackened globes and greatly increasing the life of lamps. Customers served by meter are for these reasons seldom charged for renewals of lamps excepting those lamps broken by violence. Complaints of poor light arise also from the low pressure on some of the housestop mains used to supply light to consumers on streets where no pole line has been built. These housetop mains are too small for their work and during the height of load the pressure was formed in one case as low at 95-3/4 volts and in many places as low as 97 volts. In these localities you have used some lamps of 98 volts which give a fair light when pressuerr is low but which blacken very rapidly while load is light and pressure is up to 109 + 110. The use of these lamps in such localities is a good temporary expedient but the only permanent relief is to build a line of heavy main through such districts and run a feeder to its center than your pressure can be held at 110 volts and the same lamp used as on other mains. Another cause of complaint is the distortion of balance cause by motors of 3 H.P. and upwards using 110 volts and connected only to one side of the system. If such motors are overloaded the trouble is increased, if their load is intermittant as in elevator work, the lamps respond to every change of load on motor increasing in brightness as load decreases, diminishing as the load increases, rapid changes of light cause britter compalint and do more harm than the motor reverses is worth. If such motor custormers pay enough to warrant the cost it would be wise to exchange his 110 volt motor for one of 20 volts at your cost and put the motor on an independent service wire in which went the trouble would by reduced in a remarkable degree. Complaints of poor light are at times due to inattention to regulation. Where the load is rapidly increasing, as at sunset, the engineers attention is directed to the boilers, engines and dynamos that all will be ready to meet the demand for more current at such a time the regulation of pressure is liable to be neglected for many minutes at a time during which the increasing load has reduced the pressure so as to make a very dull light and causes complaints from all quarters. While the load is not changing the pressure is constant and but little regulation is required but where the load commenced to fall the pressure rises and unless regulation is attended to faithfully the pressure will increase so as to cause serious loss of lamps by breakage and rapid blacking of lamps as well as a serious injury to the carbon from overstaining which greatly reduces its effect. The [xxx] of close and constant regulation all not so well understood by station managers as they should be or they would follow the practice of the few stations who employ one man (or a boy) to do nothing else but watch the indicators and manipulate the equalizers and regulators so as at all times to maintain a constant pressure at ends of finders, thereby obtaining a uniform and constant light when mains, feeders and apparatus are in good condition and properly propotioned to their work. Complaints of excessive breakage or short life of lamps are to be expected from consumers who always get good pressure on your circuits that is to say that those who use lamps of 102 or 103 volts who have 108 to 109 volts pressure can be expected to [diagram page] [new page] to complain of life of lamps. When load is light every consumer gets such pressure, sometimes more the highest I found was 111 volts what it is or has been while regulation was neglected we can only surmise, it is sufficient to state that 110 or 111 volts is enough to cause short life of lamps of 102 or 103 volts even with constant regulation and that any increase of pressure decreases the life of lamps greatly. Another cause of complaint of dull light and also short life of lamps, fortunately an exceptional one on your circuits, bad local balance a greater load on one side of the three wire system than on the opposite sides. This fault causes the lamps on the heavy loaded side to give a dull light while those on the other side are very bright, burn out quickly and blacken rapidly. I found but very few such cases the worst of which was in R Le. Howards barbershop #193 East 41th where at 520 oclock pm he had 100 volts on one side of the line and 111 volts on the opposite side. This caused dull light on one side and black lamps and short life and the other side. This bad balance is probably due to a motor of 110 volts if not it is caused by neglecting to balance the customers in that locality. Your balance as a whole and locally is very good and is the result of putting customers on their wire services and balancing each customers evenly. In many cases I found the pressure exactly the same on both side of customers services, in some cases a difference of 1/4, 1/2,3/4 or 1 volt between the two sides but such exceptional difference of pressure as 11 volts above quoted brought up the average difference between the two sides to 1-3/4 volts which is much better than is generally obtained by two wire services although the exceptionally high difference of 11 volts is very bad. The complaints of dull light are due in some cases to the mains having been calculated to be fed by fifteen feeders seven of which have not yet been installed. Under these conditions certain mains are made to carry current for which they were not calculated and try and the distance originally intended. This causes a drop or lowering of pressure all along such mains during the heavy loads and can be properly remedied only by providing a feeder according to the original determinations to deliver the current to the main at the point laid down on the map. This feeder would not only improve the light by returning the mains in that locality but would decrease the load on the adjacent feeders and tend to lower the station pressure and reduce loss on feeders which means a saving of coal and wear and tare. Since the overheating of the equalizers caused fires which destroyed the Edison Stations at Fall River and Boston Mass. Much stress has been laid upon the importance of protecting stations against similar disasters. Equalizers are now made with iron frame and porcelain insulation the equalizer switch being mounted upon a slab of state making the whole fire proof in itself. Place such fireproof equalizers upon a fireproofed floor and fireproof the walls and all combustable materials surrounding them and your station is safe. Boston had its equalizers in the dynamo room in plain sight so I think had Fall River, yet their stations were destroyed. How much less can you expect to escape the same consequence which your equalizers are out of sight in the left over engine room surrounded by the dryest and most combustable portions of your building. (See copy of my report on Reading Station sent out by Lamp Co.) In regard to equalizers I would advice that unless they cannot conveniently be placed in a fireproof space in the engine room that they be completely encased in fireproof materials in their present location and well ventilated to allow heat to pass off or that they be replaced by iron framed equalizers which in themselves are fireproof and in any case a fire hose be kept ready for use convenient to their location. In installing your plant the feeder known as No. 1 was made the standard feeder, this may have been right according to the indications at that time, but it is not now properly the standard feeder. The standard feeder should be that feeder which at all times has the greatest drop or in other words the greatest difference between the pressure at its extreme ends when all indicators are on zero. Such a feeder is your #10 which was the last one put into use and which serves the Hotel Ryan and vacinity of 7th Robert Struts. From that feeder should be run these #12 or #14. W.W.G. hard drawn copper wires into the station, these wires should be well insulated either K.K. insulation made by Homes Booth Haydens or Made #1. Compounded House wire made by Edison Machine Works (See their sample card #43). These three wires should be connected to the standard indicators and to the comparative indicators in the same manner as are the iron pressure wires now in use from #1 feeder. Then the #10 comparative indicators should be connected to the iron pressure wires from #1 feeders and so numbered and placid as to be easily sun and operated form #1 equalizer wheel. No. 10 is then your standard feeder and all its resistance should be cut out of circuit by turning the #10 equalizer wheels in the direction which now makes #10 indicator pointers go high and kept so in the same manner as the present standard equalizers are now done (or should be done). This change may have a tendency to raise your station pressure slightly but it will also producec the effect of keeping all your indicators up which is now often impossible without equalizing on #1. (the present standard) feeder. Your regulating apparatus, indicators, ampere meters are all of good type and in good order your street system of conductors are also in good shape, the general condition of your station is better than the average and in my opinion is excelled only by the larger and most modern stations. Concerning motors I wish to advise (and I wish I could imress the importance of this on all) that under no circumstances should you consult to serve current to any of greater capacity than 1/4 HP which is built for a lower pressure than 220 volts. The Sprague Co. build motors of all sizes, from 1/2 HP up, of 220 volts. Energetic and convincing salesmen may indeavor (as they have in other places) to persuade you that motors of 110 volts are even better than those of 220 volts, but you should not allow them to sell you, on any of your consumers, such motors and if any consumer purchases a motor of 110 volts of 1/2 HP or larger you should refuse to serve him with current. The Edison three wire system is a 220 volt system and it has no conductors which are intended for 110 volt service the neutral wire is not a conductor but a compensating wire and its only use is to enable customers to control lamps simply and not be obliged to extingish two lamps every time they turned off one. On this assumption you are safe to refuse service to large motors of 110 volts even in face of a law suit from some motor company who desire to sell motors in your city. I wish to mention casually that I think there is a chance to make money in St. Paul from arc lighting and wonder why you have not already occupied part of that territory. I deem it almost necessary to the success of your motor system that previous to starting such system you have a trustworthy man thoroughly instructed in the operation of motors by some Edison station who ahs a successful meter system and a competent meter man willing to instruct one whome you and send to them for that purpose. The plug switches on neutral wires of dynamos used to close dynamos circuits when throwing in dynamos are a poor device and should be replaced by a heavy, substantial switch such as #121 in Bergmann Ho' catalogue #6. A better form of this switch is made by Leonard + Izzard of Chicago, which bring mounted on its edge instead of on its face is more economic of space and more easily operated. I shall be glad to supplement this report by answering any questions relating to your station that may arise. Very truly yours Edison Electric Light and Power Leo of St. Paul Started up: July 1st 1887 Capacity of Machinery:4 pairs #20 dynamos each 400 amp. Or 16 ro. Amp each section Capacity of system of distribution: 1000 lamps (10c/p) original Increases since starting: 2 pairs #20 dynamos 2 boilers 1 feeder for about 1000 lamps Lamps connected: 10,443 16 c/p equivalent probably 11,000 to date. Lamps in residences : very few, amounts to nothing (1 duty 10 light) Maximum load: 2.000 amperes on each side. Max avg. nov. '88 to 1900 Average evening load: 1800 to 2000 amperes on each side avg do Lightest load: 330 amperes Sundays Ampere hours per day: about 18,000 amp hours per day Nov. 1 to Nov 25 Daily run 24 hours, 7 days each week Lamp hours per day: not separated from motor current Lamp breakage: average $400 per month about half are paid for by course at 90 cents to 16. $1.05 20 to 32. 1.55 for 50. 100 c/p $2.50 Area cover: about 1/2 mile square. Station outside of area. Number of feeders: eight Loss in feeder, full load: 22 to 24% (from 145V to 110V) Loss in Mains: varies in localities, som 15% some less than 2% Service lines: mostly 3 wire and carefully balanced. Rule is to put 6 lights or more on 3 wire service, and a separate service for each customer. Bridges in mains: half of system is will bridged, lower half suffered for bridges Normal E.M.F. of lamps 102 to 104 volts (some 98V lamps tempo) E.M.F. at feeder ends 110 volts Equalizers: have wooden frames and are located in an open left above unfine room operated from below by hand wheel on long shaft. Subject to same criticism as chester station wheels opposite comparative switches covered with dust which makes bad contact. Regulating apparatus: dynamos hand regulators on wall back of engines below standard indicators spud of engines is sufficient to give ample margin in regulators at full load. Indicators: Comparative system. All in good order. Iron pressure wires new from standard feeder, two sets one set for it. Stds, one set for the comparative. Standardizing indicator connected to switch on same circuit as std. indicators. Setting of Indicators: on wall back of engines Indicators affected by varying magnetic field: no. Relative positions of indicators to regulators and equalizers: 12 ft. or more below the equalizers, comparative 25 ft. from regulators stds one foot above regulators should be shielded slightly affected. Dynamo ampere meters: neutral wire of changing switches (on heavy board of dynamos) on cuting 15ft. From dynamos in front of regulator Main and neutral meters: 2 main amp. Meters dial pattern #108 6 or 8 ft. from de neutral amp meter #Y67 15 ft. from dynamos Dynamo galvanometer: used for throwing in dynamos Condition of dynamos and care given them: Excellent commutators smooth Hat shut copper brushes used, made by engineer, spark almost nil. Dynamos man keeps dynamos clean and in very good order. Engines running, style, number, condition 6. Buckeye double valve. First class condition. Clean and smooth running 14-1/2 x 11 255 Rev. 150 HP nominal. Boiler pressure average 85lbs, 95 during full load 80 lbs. lightest loads. Street lighting system: none, gas used. Boilers 6. 18ft x72 chester Boker. HP 150 each. Boilers 2 Root water tube HP 125 each Condition of outside lines: good, heavy line of feeders should go underground, system overloaded General condition of station: excellent clean, convenient of handling well arranged Pressure wires: all of iron insulated, all on top arms Voltmeter: mist with lamp co. Common appliances wanting: None Light, how sold, contract entirely meters to be introduced soon. Motors in operation: about 60 HP Arc Light plant operated by Gas Co. J+H Preston + M.E. by economy st. Ht. C Employees: Chf +2 assit engines, 3 firemen, 1 dynamo man, 1 oiler+ 3 wiremen, 1 lineman, Bookkeeper, buy in office managers clerk Management: board of directors, President St. Crozer Jr., Hy. Hutchinson VP, Donald Rockwell, Secty Scot H Finn Treas + Gut Mgr. has entire has entire charge of plant. Capital, limit $250, 000 Paid up, $: nearly all say 2,000 short Bonds, $no bonds Floating debt: 14,000 Financial condition good. 2% div. declared nov 20 88. Some earnings applied to liquidating floating debt. Competition: Nesting house incadescent 2,000 lamps operated by Gas Co. now increasing to 5,000 lamps Active officers: At stat 7, now only one. Monthly reports: sent to Edison El. Lt. Co. Lamps counted and sorted: and tested now for vaccum and sound perviously not unwrapped but counted and sorted Customers lamp acocuntkept by bookkeeper about 1/2 consumers per for renewals of lamps 90 cent to 20 c/p to 32 cp 105 cents, 50 c/p $1.55 10 c/p $2.50 each When meters are installed installed those customers paying by meter will free lamps.
Thomas A. Edison Papers, School of Arts and Sciences, Rutgers University