charger(redirected from Chargers)
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(1) An electrical-engineering device for charging storage and capacitor batteries (mainly the former type). It consists of a charging generator or a transformer with a current rectifier, and a power switchboard that contains voltage regulators and automatic circuit breakers. The power of the charger depends on the capacity of the batteries being charged and the rated duration of the charge.
Storage-battery chargers are used for periodic charging, compensating and interrupted recharging, and equalizing charging of storage batteries, which, as a rule, are first grouped according to their capacity and the strength of the charging current. For periodic charging the storage batteries are divided into two groups. The charger charges one of the two groups at a time. For compensating recharging the charger feeds the load circuit and simultaneously recharges the storage batteries. For interrupted recharging it feeds the load part of the time and recharges the storage battery; the rest of the time it serves as a standby under a low load. The load circuit is fed by the storage battery. Capacitor chargers are used to charge capacitors in the normal mode—that is, continuously up to the rated voltage.
Low-power single-phase rectifier chargers have a steeply falling external characteristic suitable for the charging conditions of storage batteries. The voltage is regulated by means of a tapped secondary transformer winding.
G. V. MIKHNEVICH
(2) In blasting operations, a charger is a mechanism or machine for filling a charge hole with explosives. Chargers are divided into two groups: units for charging stick powder that does not contain nitroethers or cyclonite and units for charging granulated explosives. The units in the first group have not become widespread because of their low efficiency, the inadequate charging density, and the high cost of suitable explosives. Chargers for granulated explosives are designed to charge descending blastholes in pits by gravity flow of bulk or fluid explosives (portable mixing and charging equipment that produces a mixture of the explosive components, such as igdanit or granular granulit, during the charging process and transporting and charging machines for factory-made explosives) and to charge blastholes and wells in any direction by pneumatic equipment. Pneumatic equipment is preferred for mines and is subdivided according to its principle of operation into ejector types, in which the explosive is sucked up from an open container by a vacuum in an ejector head and carried along by a stream of compressed air into a charging pipe, and pressure types, which force the explosive from a sealed container by compressed air. The pressure chargers transport the explosive along pipes or hoses for 200–300 m (including 80 m vertically) and force it into the hole with the required velocity. Chargers for fluid explosives containing water are divided into two groups: mobile machines, for moistening dry factory-made mixtures of the akvatol type, and mobile thermally insulated machines, for transporting granular components and a hot solution of ammonium nitrate (filler) and mixing them directly during the charging operation. The fluid explosive is forced into the hole by compressed air or a pump.
REFERENCEMekhanizcitsiia z.ariazhaniia VV. 2nd ed. Moscow, 1969.
G. P. DEMIDIUK and V. M. KOMIR