The photograph on the previous page shows a typical unit. The ventilated case has shielded air vents and a solid top and bottom,
so that dirt ingress is kept to a minimum.
The charger section is rated continuously at 30 Deg C ambient, and is a half-controlled thyristor system for single-phase
operation. A further control circuit provides overvolt with relay alarm contacts for external telemetry. The charger fault alarm is also
connected in circuit and the connections brought out to the front panel.
The charger has an automatic BOOST operation on start-up, and reverts to FLOAT operation once the battery terminal voltage has
reached a preset figure. This eliminates the need for manual Boost operations by the operators and eliminates the possibility of
an overcharge situation arising. All settings are adjustable.
Output smoothing is standard on all our chargers, and the units will operate without battery if required, as stand alone power supplies.
Wiring is heavy-duty flexible stranded type with hexagon-crimped copper-tube terminals onto bolted connections throughout.
A three-phase unit is not offered currently, as there is little demand for such low outputs, but we would consider designing such a unit should
there be a significant requirement for such a system.
Indicators are provided for AC ON, CHARGE, INHIBIT, FAULT, BOOST and FLOAT. No mains isolator and output control switches are provided as the
unit is intended for continuous 24 hour operation. These controls could be added to suit a specific requirement.
The main components including the transformer, choke, capacitors, thyristor stack and heatsink are all grouped inside
the main chassis for protection, and the whole assembly is covered by a 16g/1.5mm sheet steel body and cover. All parts are rated for long and continuous operation and
have some reserve in hand over and above their continuous rating requirements.
We recommend that batteries have no more than 4 X the rated output of the charger for a fast charge, or up to 10 X the rated output for slow and
overnight charging (40AH and 100AH for a 10A output charger.)
© Prepair Ltd 1990-2005 E&OE
TECHNICAL DESCRIPTION.
The CVT554 charger comprises a medium-power, fully rated constant voltage charger, contained in a chassis and
casing which is designed to be wall mounted in a permanent installation. Fixing holes are pre-punched and cable access is external
to covered terminal blocks.
CONSTRUCTION
The system is built around a 2mm sheet steel chassis, to which all the main components are bolted.
(We do not use anything other than threaded fasteners, and all are either stainless steel or zinc plated)
AC POWER SUPPLY
The chargers are available with single phase input as standard, plus we can offer 110V or 415V AC (phase to phase) inputs as
options. Note that operation at 110V input effectively more than doubles the required AC supply current compared with 240V input.
BATTERY TYPES AND CAPACITIES
The chargers will operate on any type of battery that will accept the rated output of the charger. Typically, vented Lead-Acid and Nickel-Cadmium
types are usual, most applications comprise these battery types. The charger will also charge NIFE and Lithium-Ion batteries of suitable voltages and capacities.
CONNECTIONS.
The standard units have external covered terminals, separated into AC Input and DC Output / Alarms.
TYPICAL USERS
The CVT554 wall units are in service throughout the UK on standby duty for various utilities and users. The voltage ranges available are shown below,
plus we are able to offer a customised output voltage and current range for OEM customers.
STANDARD VOLTAGES & OUTPUT CURRENTS
The chargers are available with the following standard outputs:
24V 5A
18V 5A
12V 5A
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