STORAGE BATTERY AND CONTROLING BOARD.
ALL the universe is maintained alive by the agency we call electricity. The light of the sun, without which no life can exist, is electricity; and when our atmosphere becomes foul and unhealthy, it is the electricity that cleanses it and renders it fit to breathe. It is the only known agency that annihilates distance, abridging the enormdistance of 190,000 miles; or seven and one-half times round the world, in a second. This agency abounds in nature, and we are privileged to generate it artificially to make use of it for almost unlimited purposes, one of which is to convey intelligence in fire and police telegraph systems of civilized nations.
For such systems of Intelligence some source of electricity is employed which traverses the entire circuit from transmitter to receiver. There are several known sources whereby electricity may be obtained— namely, natural and artificial sources. By natural, we mean the earth as an immense cell of battery, by which a telegraph line of forty miles in length has been successfully worked. The artificial sources can be classified into four distinct branches; Chemical, dynamical, static or frictional, and thermal. This last is uneconomical. Static electricity is not adaptable for our subject matter. Dynamic electricity is used in some instances, and chemical is almost universally used for telegraphic uses.
Up to within a few years almost the only battery used for telegraphic purposes was the gravity or bluestoue battery. This gravity cell in normal condition will show about one volt, and its Internal resistance varies from three to six ohms. Consequently, we find by ohms’ law, that, In order to send one-tenth of an ampere into the line from one cell of battery, it must not meet with more than ten ohms resistance, and of this it has from three to six ohms resistance within Itself. 80 It follows that, where a telegraph line has a high reaisteuce to overcome, it requires a large number of cells of battery to operate it successfully. Each cell occupies eight inches of space, and a large number will take up much valuable room. Those of you who are still operating your Are or police telegraphic systems by the old gravity battery have visions of the batteryroom. with long rows of shelves decorated with glass jars in variegated colors of blue liquids, with oopper stalagmites and stalactites joining each other inside of the many cells; a corps of assistants trying to keep them clean and up to the standard; in one corner, a heap of deposited copper and old zincs; here,several barrels of blue-stone; there, new zincs, jars, coppers, and whatnot; work never done; always muss and confusion. Are you tired of it? Are you keeping abreast of the times; and do you know that a great stride has been made in electrical methods of operating telegraphic systems? Great minds have beeu concentrated on the production of a secondary or storage battery whereby electrical euergy could be stored up and delivered at will. Primary battery generates electricity by consuming some metal, while a secondary battery receives the electrical current called “charging”—its elements becoming oxidized under a tension. That is, this oxidation has a tendency to deoxidize to a great extent, thereby forcing most of the electric current it has received in a reverse direction, called “discharging.” The Western Union Telegruph company several years ago adopted the storage battery for their electric power, displacing thousands of cells of gravity battery ;and now their lines are operated by dynamic current and storage battery almost exclusively. Of the various storage batteries now in use we might mention three: First, lead battery ; second, lead-zinc battery; third, nickel iron battery (or Edison).
The lead-zinc battery gives nearly three volts when fully charged; it works between two and two and onehalf volts, then suddenly drops to one-half volt. It is this sudden drop that renders it unfit for fire aud police telegraph purposes ;but besides this undesirable trait, the life of tbe elements are subject to sudden collapse. The nickel-iron, or Edison Btorage battery has one and one-tenth average volts, which is about one-half of that of the lead battery; but its weight is claimed to be one-half of lead battery. The essential points of merit claimed for this battery, are the indestructibility of tbe elements, the reduction of time of charging, and its comparatively light weight. This buttery is not yet perfected and placed on the market, and is designed for traction power at the present time.
The battery we are interested in is the lead battery, as adapted to fire and police telegraph systems. This battery has a mean voltage of two volts, with Internal resistance so small(aboutone hundredthobm)as to be ineligible; therefore, It is capable of delivering onetenth of an ampere through an outside resistance of twenty ohms. Nor Is this all; by reason of its low internal resistance, any number of branch lines may be supplied from one battery, or, in other words, any amount of current may be taken from one storage cell within certain limits This is not the case with primary battery.
*Paper read at the convention of the International Association of Municipal Electricians, Niagara Falls, N. Y., September, 1901.
Storage battery does not consnme any chemicals, and, theoretically, it is indestructible; but charging and discharging will eventually loosen the active parts and cause disintegration; leaving, however, a safe margin far ahead of the primary battery. Storage battery does not require the scraping, cleaning, and frequent renewals that primary battery does. To replenish a storage battery the only thing needed is to charge it; aud this is done by simply moving a switch. And the actual cost of maintaining a storage battery for several years is the cost of the current used for storing purposes, and is a small fraction of the cost of maintaining gravity battery.
Very early in the history of storage battery the Gamewell Fire Alarm Telegraph company saw the great benefit and advantage that would accrue from the adoption and use of storage battery to operate its fire and police telegraph systems; and its electrical experts were set to work to devise instruments and means to safeguard and control the use of this battery, and they have produced the most scientific, simple, and positive switchboard for that purpose yet made The city of Wilmingtou was equipped in July, 1896, with storage battery and the Gamewell standard controling switchboard for operating the fire and police telegraph systems. This new battery displaced 580 cells of old gravity battery, and made available a large space occupied by the old battery. Those of you who have not yet adopted the new battery, have yet to feel the security, comfort, and satisfaction, to say nothing of tbe economy in labor and maintenance deiived from its use.
In installing a storage battery for closed circuit work, it is absolutely necesbary to have a duplicate set of battery for each circuit, one set of battery operating the circuit, and the duplicate set being charged up to standard. This gives a wide margin of safety—there being always a battery inreserve absolutely disconnected from the other aud notsubjected to to outside influences. To charge and discharge properly, many batteries of various numbers of cells there must be proper devices, instruments, and switches so arranged as to simplify the operations, lessen the chance of mistakes, and prevent waste. For this purpose a well equipped central office should have a switchboard containing the terminals of all the batteries and terminals of all the signal lines, with gangswitches so arranged that the batteries can be changed from charging circuits to the signal lines, and from the signal lines to the charging circuits by one motion, and without the possibility of forgetting some of the lines or misconnecting the charging circuits so as to injure or destroy the battery by cross-connections or reversals. Tbe switchboard should be adaptable and adjustable to the voltage of the charging circuit to be used, aud should have facilities for grouping any nnmber of batteries in series or multiple series for charging, so as best to economize the charging circuit. The battery should be protected automatically from the charging circuit In case of reversal of polarity or short-circuiting or stopping of the current, by opening all the battery terminals at once automatically. To make the switchboard perfectly flexible and adaptable to requirements, rheostats, with resistance from twenty to 160 ohms, are inserted in each charging and discharging line, to enable the operator to regulate perfectly the rate of charge or discharge. There must also be measuring instruments (volt and ameter) for immediately showing the voltage and amperage of the circuits, both line and charging, by plugging them into the circuit desired to determine the condition of the batteries and the rate of charge or discharge.
The life of storage battery depends largely upon fair usage. With intelligent and judicious handling there is no reason why a battery should not do good service for many years without renewals. Some of the canses that tend to shorten the life of a battery are over-charging, under-charging, fast charging or shortcircuiting, too strong electrolyte, too weak electrloyte, exposure of the active elements to the atmosphere by not covering them with the fluid, and disturbances of the battery. Over-charging causes loosening of the peroxide from its frames, aud it crumbles down and falls out. Under-charging canses the battery to sulphate, and the Balts creep over the elements and jars, establishing a new path for the already enfeebled currents. Fast charging heats the elements, causing them to bulge out of the grid pockets and eventually to go pieces. Fast discharging or short-circuiting produces the same effect as above, only more intense. Too strong electrolyte causes internal action. Too weak electrolyte strains the battery In giving out the required current. Exposed active elements—that is, when the cell is not properly filled with liquid, causes chemical disturbances in tbe cell. For fire and police telegraph purposes the electrolyte should be of 1,200 degrees specific gravity when the battery is fully charged.
A strong battery plant properly installed, with controling board as above mentioned, a low reading volt meter to test each individual cell of liattery.a hydrometer to ascertain the density of the electrolyte, and a well ventilated battery room, can be cared for by one attendant, where it would require ten men to take care of the same nnmber of cells of old primary battery. The steam engineer by his instruments knows at all times times the pressure he has in his steam boilers, the level of the water,and the condition of the fires; also what pressure his engine requires to carry its load. So it is with the attendant in charge of storage battery—“He knows where he is at.”