New from Adelsystem is the ‘all in one’ family of uninterruptible DC power supplies. The product offers reliable, consistent backup of the DC supply, and can be incorporated where frequent power outages or dips occur. These products are particularly useful where there is a PLC or other digital communication.
The DC UPS prevents the system from falling over due to power failures and negates the need to continuously reboot the system.
The system consists of three devices – the power supply, battery charger and backup module. The power supply section is a switched mode device. The battery charger circuit is microprocessor-based, and uses smart battery management to ensure the cells are in prime condition. Visual and relay outputs warn of battery problems or failure.
The backup module ensures that the available power is automatically allocated between the load and the battery. Supplying power to the load is the first priority of the unit, after that the power is used to charge the batteries. In power boost mode, power is available simultaneously from both the power supply and the batteries, making the maximum current available two times the rated current of the unit. This is used for short time periods of high current demand.
Wide input voltage (115–230 V a.c. or 400–500 V a.c ) coupled with a selection of output voltages (12, 24 and 48 V d.c.) reduces the spares holding requirements. Different versions offer from 3 to 20 A of current. Designed to offer safe operation, protection features such as short circuit and overload on the output, high insulation between primary and secondary, protection against deep battery discharge, protection against reverse polarity connection and detection of batteries with incorrect voltage are standard.
The battery charging circuit is microprocessor-based and contains charge curves for various types of batteries. Open lead acid cells, sealed lead acid cells, Gel and Ni/Cd types are all catered for. These curves are user selectable by means of jumpers. Multi-stage charging (with boost, trickle and recovery modes) ensures a fast recharge and also the recovery of deeply discharged batteries.
The maximum charging current to the battery is user adjustable by means of a potentiometer on the front of the unit. To protect the battery, the unit will shut down when the cell voltage reaches 1,5 V, avoiding deep discharge and battery damage. The unit also performs a battery life test and guarantees battery reliability by continually testing the internal impedance of the cells. The system, through a battery stimulation circuit, is able to detect sulphated batteries and those with short circuited cells.
LEDs and relays contacts are used to signal system conditions such as main or backup supply, battery flat, no mains supply, battery fault, low battery, battery charge mode and help. The devices are completely automatic and can be customised to meet the needs of the user and the requirements of the application. After installation it is possible to carry out functional software updates using a laptop computer.