Becker Mining South Africa has developed an uninterruptable power supply (UPS) back-up system to protect plc systems which control critical functions at mines.
“These operations include all conveyer belt safety systems installed, such as gas monitoring and speed, slippage and load control instrumentation,” explains Nico de Lange, Vice President: Operations & Systems, Becker Mining South Africa. “In the event of a power outage, the PLC would not be able to function without the back-up of a reliable UPS system. The interruption of belt system and sensor monitoring would prevent normal operations and lead to costly downtime and could also become a major safety issue.”
During a power outage, the UPS system needs to supply the specified load to ensure that the electrical system continues efficient operation for a specified time period. In this project, the 3.5 kVA system, with a two-hour back-up time, has been designed to supply a full load current of 15 Amp at 220 V. This ensures the PLC system, with multiple outlets, runs efficiently even in the event of a power failure.
As this PLC system consists of many electronic devices, a pure sign wave is required to reduce induced electrical noises generated from the circuit. Without this critical feature, electronic components could malfunction and become a major safety risk, also causing costly downtime.
The enclosures of Becker’s UPS systems have an International Protection rating of IP 65, which guards against the ingress of dust and jets of water. This protection feature is particularly important in arduous underground conditions.
These inter-connected UPS systems, with Ethernet and RS232 connectivity, can be controlled or remotely managed and monitored from the control station. This means that in the event of a system failure, critical decisions can be made ahead of schedule to prevent a disaster or unnecessary downtime.