Fig. 1,155.—Vibrating unit of Edison alternating current rectifier. M, permanent magnet; N, carbon vibrating contact; O, comb radiator; P, primary circuit coil; Q, vibrator adjustment screw.
Fig. 1,156.—Elementary diagram of connections.
Operation of Edison Rectifier
The operation of the Edison rectifier may be explained as follows with the aid of figs. 1,154 to 1,156 (the parts being uniformly lettered in the figures): The primary circuit taken from the alternating current mains by the cord B, embraces the primary winding of the transformer T, a condenser C, and the coils P, of the vibrating units, [fig. 1,155].
The secondary circuit from the transformer embraces the massive carbon and copper contacts (N and O, [fig. 1,156]) which pass only the positive waves of the alternating current, for charging batteries or other duty.
An ammeter and rheostat may be placed in this charging circuit if the current is to be varied, or a fixed connection may be substituted on the base of the rectifier if it is to be used for the maximum duty of 8 or 16 amperes.
The vibrating unit ([fig. 1,155]), which operates in a manner similar to the well known action of a polarized relay, includes a permanent magnet M; the coil in the primary circuit P; the vibrating armature of steel with removable carbon contact N; the stationary copper contact with comb top for heat radiation O, and the screw Q for adjusting the amplitude of the armature vibration.
The vibrating armature of each unit is divided into two parts, which gives flexibility, affords increased current capacity and minimizes sparking, the two leads shown being connected together in one circuit.
A primary relay and a secondary switch (E and F, [figs. 1,154] and 1,156), close their contacts when current is flowing.
Upon failure of the main alternating current line they operate to open the charging circuit. A storage battery is thus prevented discharging through the rectifier.
Upon resumption of the main alternating current, the rectifier starts automatically.
Every battery room should be provided with a water tap and sink. The floor should be paved with vitrified brick, preferably blue or yellow in color, of diamond pattern and sloping in all directions toward suitable drains. A floor of this type can be easily washed by flooding with water, and its patterns tend to keep it dry under foot at all times. Wooden floors are rotted very quickly by acid spillings and by the spray.
The room should be kept absolutely clear of everything, which may be injured, by the sulphuric acid fumes and it should be well ventilated to insure the safety and good health of the attendants.
A battery, even at rest, gives off hydrogen which when diluted with air forms a mixture which is very liable to explode if brought in contact with any kind of flame. Unless proper ventilation be provided, the breaking of the connection when a current is flowing, or the lighting of a bare flame lamp in the battery room would be dangerous.
Battery Attendants and Workmen.—Those employed in setting up batteries are liable to suffer from soreness of hands and the destruction of clothing unless proper precautions be taken to prevent the same. In order to avoid these troubles, the boots should be painted with paraffine mixed with an equal quantity of beeswax.