The photograph on the previous page shows one of the first two units. The cabinet houses all the parts (except for the desktop PC) which are
required to run the system. A special connection bar is made up to suit a specific battery tray, so that connections to the battery cannot be
inadvertently mis-connected. All operator controls are door-mounted, and an emergency stop facility is provided for immediate shut-down of the
test in progress.
The charger sections are rated continuously at 30 Deg C ambient, and are fully-controlled thyristor systems for three-phase
operation. Single-phase operation is also available. Each charger consists of the standard CVT5523 control system as already used in
our standard charging systems. Output smoothing is standard, and each charger takes its supply from a common mains isolation transformer
located in the base of the cabinet on a box section steel frame. Wiring is heavy-duty flexible stranded type with hexagon-crimped copper-tube
terminals onto bolted connections throughout.
The PLC is an Allen-Bradley SLC500 type, with a proprietary programme running the application. The PLC has a number of external sensing relays
which pass it information on the battery voltages, which in turn control the steps of the testing process.
The Data Loggers used are electronically independent from the tester and the desktop PC, communication between the loggers and the PC is by
RS-232 cable. A galvanic isolator is provided in the RS-232 link to prevent false voltage levels between the PC and the discharge tester from affecting
the data flow and control. This was found necessary during development of the system. All the loggers are located in a substantial die-cast housing
on the back of the unit, adjacent to the load bank resistors. The loggers are 'armed' before testing starts by software control, the actual start of logging is
controlled by the PLC which also switches the test loads on. After completion of the testing, the loggers have to be stopped and the data saved to hard disk.
The PC supplied can display data as graphs if required, or the data can be exported in various file types for processing elsewhere.
Load resistors are fan-cooled wirewound types, with values to suit the load current required. The 110V resistors are air-cooled with pressure cooling
by twin fans, the 24V resistors are heatsink mounted with twin fans for cooling. All fans are long-life ball-bearing types, and only run during the actual
battery discharge periods.
Indicators are provided for:
Charger Sections:
AC ON, CHARGE, INHIBIT, FAULT and CONNECT.
PLC Sections: BATTERY, DISCHARGE, CHARGE, SETTLING, TESTING, CHARGE, TEST OVER. All indicators are LED types.
A mains isolator and DC output circuit control switches are provided, which override the PLC control if required. A separate voltage
monitoring system looks at each charger output and disconnects the battery from the charger should an over-voltage exists for
more than 15 seconds. This is totally independent of the PLC and other sensors, and is provided as an additional safety measure.
Ventilation is provided for dissipation of the heat inside the cabinet, and a top canopy prevents any dust or debris from falling inside the cabinet. All circuits are
fully fused or protected by and MCB. The test loads have BS88 fues and links, the thyristors have open semiconductor fuses, the AC input circuits have an
MCB and each of the control PCB's has its own on-board fuses.
The unit shown is for operation on both 110V and 24V battery sets. The chargers have an output rating of 10A (110V) and 25A (24V) The discharge
testing loads are similarly rated. Other ratings are available, please contact our technical staff.
© Prepair Ltd 1990-2005 E&OE
TECHNICAL DESCRIPTION.
The Battery Tester shown comprises a pair of high-power, fully rated constant voltage chargers, two test load resistor banks, a controlling
PLC unit and the associated controls and indicators to operate the unit. High-resolution data loggers (12-bit) are used to monitor and record the testing process.
A standard desktop PC running Windows 98 is used to control the loggers and store and display the results of the tests.
CONSTRUCTION
The system is built inside a standard sheet steel cabinet, which has a large galvanised steel chassis plate bolted to the back face, onto which all the main
components are bolted. The mains transformer is separately mounted on a heavy-duty steel frame in the bottom of the cabinet, connection terminals are DIN-rail
mounted to this frame.
AC POWER SUPPLY
The systems are available with three-phase input (3-phases + Earth, no Neutral is required) as standard, plus we can offer other inputs as options. Note
that operation at 110V AC input may be a problem for the user due to the heavy required supply current compared with 3-phase input.
BATTERY TYPES AND CAPACITIES
The system can be configured for any type of battery, typically, vented Lead-Acid and Nickel-Cadmium types. Most applications comprise these
battery types. The charger will also test NIFE and Lithium-Ion batteries of suitable voltages and capacities.
CONNECTIONS.
The standard units have internal DIN rail mounted Klippon ST5 terminals. A special cable connection bar was made for the first two units, that closely
matched the battery tray terminals on test, thus preventing incorrect connection.
TYPICAL USERS
The first two units are in service in the UK on a rail operator application. The voltage ranges available are shown below,
plus we are able to offer a customised output voltage and current range for OEM customers. Any heavy user of batteries and cells that needs to have the
facility to accurately test product could use this equipment. It also charges the batteries up at the end of each test.
STANDARD VOLTAGES & OUTPUT CURRENTS
The chargers are available with the following standard (nominal) outputs:
110V
60V
50V
24V
12V
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