S T O R A G E B A T T E R I E S
General Principles
The operation of the storage batteries is taken up first, because the equipment will not function successfully unless the batteries are properly handled.
One set of storage batteries, called the "H" batteries, is used to supply magnetizing current to the receivers attached to the horns, and two other sets, Fl and F2, supply filament current for the amplifiers, exciting lamps, etc. The Fl and F2 sets are used alternately, one set being on charge while the other is running. It is very important to always follow this practice, which is necessary in order to maintain the charge and ensure that adequate filament power will be available for every show.
How long to run each set of batteries before putting it on charge will depend on the extent to which the equipment is used; furthermore, the charging period may be different for the F sets as compared with the "H" set. This makes it impossible to lay down any general rule as to how long each set should run. It is therefore essential to use the hydrometer supplied with the batteries, to find out when each set needs charging.
Hydrometer
As a storage battery becomes discharged and loses its energy, there is a corresponding fall in the specific gravity of the acid - that is, the weight of the acid in comparison with the weight of an equal volume of pure distilled water. Knowing this figure for any battery, it is possible to tell at once whether or not it needs recharging. The hydrometer is an instrument for ascertaining the specific gravity of the acid in a battery--usually called for short "the battery gravity".
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S T O R A G E B A T T E R I E S
Battery Charging
l. Check condition of batteries EVERY DAY with hydrometer. For this purpose, select one cell in each battery group for use as a pilot cell, and read gravity in each of these cells by removing filling cap and drawing enough acid into hydrometer barrel to lift float. After reading, replace all acid withdrawn and put cap back. Never measure the gravity just after adding water; wait until battery has been on charge long enough to stir up solution.
2. Enter gravity readings on Battery Log Sheet we supply. This is very important in order that our engineer may have proper information to enable him to service the installation.
3. As soon as gravity of pilot cells of any set in use has fallen to 1200, put this set on charge, as described on next page. NEVER let gravity get below 1190, as this shortens life of battery and has bad effect on operation of equipment. On the other hand, do not start charging above 1200, as batteries will then be worn out by too frequent charging.
4. When gravity of set on charge has risen to between 1270 and 1285, take this set off charge.
5. Our engineers adjust charging rate so that as a general rule if one "F" battery set, is on charge while other is in use, set on charge will reach full charge value by the time set in use is down to 1200. If you find. that it is often necessary to make period of charge longer than period of operation, report matter to our service engineer on his next visit.
6. When equipment is not being used very much, acid gravity may not fall to charging point in a whole month. At such times, charge batteries every month.
7. In connection with the use of the hydrometer, change the pilot cell every month so that all cells will be used in turn and loss of electrolyte through dripping, etc., will be equalized.
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S T O R A G E B A T T E R I E S
Operating Battery Panel
To prepare for operation of equipment, proceed as follows:
1. Set at "Operate" control switch for "F" battery set which is to be used.
2. Set at "Charge" control switch for "F" battery set which is to be charged.
3. Set at "Operate" the switch controlling the "H" batteries.
When finished operating, open all above switches, with the following exceptions:
1. If additional charging is needed for "F" battery set, that has been on charge, as explained previously, keep the switch controlling this set at "Charge" until gravity reaches full charge value.
2. If "H" batteries need charging, set switch controlling them at "Charge" and keep it there until gravity reaches full charge value.
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S T O R A G E B A T T E R I E S
Maintenance
If the storage batteries are to realize their full life and cause no trouble, they must have proper care and attention. The following points are for this reason very important.
Water
Never put anything into a storage battery except clean DISTILLED water.
Battery makers put a certain amount of acid, diluted with water, into each cell when new, and no more acid is needed. As the water evaporates, it must be replaced from time to time so that the solution keeps the plates completely covered.
EVERY WEEK, on the pilot cells, and EVERY TWO WEEKS on all the other cells, look at the acid level. To do this, remove the caps and use a flashlight to illuminate the cell interior. The acid level should be about a quarter of an inch above the top of the plates. It should never be allowed to get down to the top of the plates, and on the other hand, it should not, touch the bottom end of the filling tube.
Add the necessary amount of water by running it in slowly BEFORE charging. Batteries require more water in hot weather than in cold weather.
Distilled water may be obtained at any drug store or battery service station. It is best to buy it in large bottles of one gallon to five gallons capacity, and fill
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S T O R A G E B A T T E R I E S
Maintenance
Water
the cells either directly from the bottle through a, rubber tube, or else by a special filling cup. Do not use a hydrometer for this purpose. If you are not already provided with such an arrangement, our service man will show you how to set up a distilled water bottle with glass tubing and. rubber hose.
Cleanliness
Keep the battery tops clean, not merely for the sake of appearance, but to obtain better service. If you are careless in using the hydrometer, and drip acid. on the batteries, or if you leave the filling caps off and allow the fine acid spray, coming from the batteries when they are charging, to be deposited on the battery tops, you invite short circuits and. noise in operation. A little acid mixed with dirt from the air in the room will soon form an electrical leakage path on the battery top between terminals, which may prove very objectionable. Once each week wipe off the battery tops and connectors with a rag moistened in a solution of baking soda in water, or a solution of household ammonia, and water in equal parts. Occasionally after cleaning, coat the battery terminals with vaseline. Remember, too, that even a very small particle
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S T O R A G E B A T T E R I E S
Maintenance
Cleanliness
of dirt getting into a cell may reduce its efficiency and its life. Therefore, ALWAYS KEEP THE FILLING CAPS SCREWED ON TIGHT, except when testing the gravity, or adding water. The little vent holes in the caps will take care of the gas driven off in charging.
Miscellaneous
If for any reason batteries are not. in use, keep them fully charged. and test their gravity and add water once a month. Connections must be tight, at all times. Occationally check both the outside connections and the cross straps between cells, to ensure they are tight. and good connection is being made. Never bring open light or flames of any kind into the battery room. Keep the battery room ventilated at all times and keep the batteries dry.
Responsibility for Batteries
To ensure proper care of the storage batteries, one person should be given full. responsibilty for them, and should fill out the Battery Log Sheet we supply; no one else should touch them.
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