The battery charger (DC Power system) shall have two Output voltage settings namely float & equalize, selected automatically and by a panel mounted switch. It shall comprise an isolation transformer, an SCR full wave rectifier, control circuitry, metering, alarm & protection.
An electronic control module with polarized plug and receptacle shall be used for easy removal and installation. All components shall bear the manufacturer's identifying markings and, except for electronic circuitry and transformers, be commercially available in major centers. All components shall be suitably sized to carry the full load continuously under all stated environmental conditions. The unit shall be convection cooled (no fans). A transformer shall in all cases isolate the DC from the AC source. The charger shall be housed in an EEMAC1 wall mount sheet steel cabinet having a hinged door with closing devices requiring the use of a tool to open, or be assembled on a cubicle mount panel. The charger shall be finished with ASA61 grey baked enamel over primer.
The AC shall be rectified by an SCR full wave rectifier mounted on extruded aluminum heat sinks. The SCR firing shall be controlled electronically.
An SCR firing control and alarm module shall be connected by a polarized plug and receptacle type connector and fixed with screws to the front panel on metal standoffs for ease of installation and removal. Indicator LEDs and the charge mode switch shall be mounted on the module. The module shall limit the current, and regulate the output voltage to +/- 1/2% of setting for any combination of +/- 10% variation in input voltage, O to 100% variation in load, and +/- 5% variation in line frequency without the use of internal or external dummy loads. In addition the module shall include the following functions and alarms:
The float and equalize voltages, the current limit, as well as the alarm trip points shall be adjustable by means of individual multi turn potentiometers mounted on the module and adequately identified. The module shall be adequately coated with an appropriate varnish. Module components shall be identified by means of a silk screen for ease of repair and trouble shooting.
Instruments, Indicators & Controls
The following instruments, indicators, and controls shall be included as a minimum:
The alarm signals shall be extended to individual Form "C" Dry Contacts for remote indication.
The units shall be Cigentec inc. type CG or CB as determined by the specification.