In today’s world of technology, almost everything is controlled by some kind of electronic memory device. With the ever-increasing use of these memory devices, there is an ever-growing need to protect such critical items from not only power failures but also bad power supply conditions from your electricity producer.
In countries with unreliable power supply grids as we have in South Africa the reliability of the National power supply grid is further hampered by the heavy industry associated with South Africa core economy in particular mining and smelters.
These heavy industries are responsible for introducing many harmful effects into the grid that will cause damage to any sensitive electrical equipment on the same dirty power supply grid as well as data corruption in all walks of the industry from controlling circuits for big machines to computer system processors in large data centres.
It is a proven fact that the most significant cause of data corruption and electronic hardware failure is by far bad power and NOT power failures.
Bad power is a wide-ranging term that is used to cover words like dips, spikes, brownouts, surges and peak voltages and currents. Bad power supply comes in a wave of different forms and is highly unpredictable other than it will damage sensitive loads in particular electronically controlled equipment that uses data as a means of controls.
The only way to protect all of these electronic memory and control devices, is to install an on-line double-conversion Uninterruptible Power Supply System also commonly known as a UPS system, with an associated backup battery which can either be installed inside the UPS box in most cases where the UPS is single-phase or alternatively the backup battery is either installed in a separate steel battery cabinet or on a battery stand. The backup UPS system thus sits between the critical connected load and the bad mains supply grid and prevents any bad power on the grid from getting to the critical UPS inverter load.
Battery stands are either constructed of steel or wood or polywood which is a form of extruded recycled plastic. However, polywood is not as “green” as it makes out. Generally speaking the steel backup battery box or steel backup battery stand is the most common form of UPS battery housing.
Polywood battery stands are made from recycled plastic bags, but they have a huge negative impact on the environment in that the polywood extrusions are not recyclable at all and all offcuts, that are milled off to square off the extrusions, end up in landfills and they are not biodegradable at all nor can the plastic be economically melted and reused.
It is thus highly recommended that polywood battery stands never be used and that rather wood is used to make battery stands as it is 100% recyclable, from a sustainable and renewable source and easily biodegradable, while still lasting many years longer than the UPS backup battery that it houses.
The UPS is thus a “blocking device” or “one-way valve” that stops this bad power that exists on the mains supply grid from affecting the load.
- A UPS ensures that the connected UPS inverter load is 100% completely isolated from the bad mains supply and is thus the critical loads are not affected irrelevant on what is on the input side to the UPS.
- The UPS does this, by firstly converting the bad mains supply from AC power into DC battery power. This is done with electronic circuits and power electronics and is called a rectifier. (AC to DC conversion which is the 1st conversion)
- The DC battery power from the rectifier is then used to charge the connected backup battery bank and feed DC power to the UPS inverter input stage. This common linkage area where the rectifier connects to the backup battery and the inverter input stage is called the “DC link” or “secure bus” in a UPS system.
- Then the UPS uses its inverter, which is basically a rectifier working in reverse gear, to convert the DC power on the secure DC link into AC power for the critical load. This is the second conversion process and is the complete reverse process to the first conversion process. The inverter does this by a process called pulse width modulation or PWM and essentially it sends controlled DC pulses of different heights and widths to form a rough Sinewave power that is then further filtered by the inverter filter circuits into a clean, pure Sinewave power to back up the critical loads connected to its output.
Because there are two conversion processes of power ie AC to DC and then DC to AC again, the UPS makes sure that the critical load is completely isolated from the bad mains supply, no matter what happens on the input mains supply side.
A UPS keeps the load running happily, all the time.
Under normal UPS operation conditions the 1st and 2nd conversions of power carry on happily until the power fails or until the power supply is so bad that the rectifier (1st conversion) cannot work. When this happens, the UPS battery kicks in immediately to back up the critical load without any break in power to the load.
The battery backup supplies its DC power into the inverter input stage to create AC power for the load in the second conversion process. This ensures the inverter critical load stays on and working giving time for the UPS user to switch off the connected critical inverter loads in a controlled manner before the battery goes flat or in some instances, this can be done automatically, without any human intervention.
be automatically shut down in a controlled manner with work in the process being saved in a file. After all the connected critical loads are shutdown the UPS will then switch off completely to preserve the backup battery power still available. Once the rectifier input power supply returns or is within acceptable limits, the UPS will start up automatically and power up the critical inverter loads.
Because the connected inverter loads are shut down in a controlled way, there is no data corruption or component failure, like that which happens if the power suddenly goes off.
Smart communication software for automatic data saving after a power failure and controlled shut down of the UPS connected inverter loads
It is also possible to connect IT type loads as well as industrial communication highways such as Modbus, JBus and many other communication protocols and highways, for remote network management and monitoring via an Ethernet connection to the UPS via an optional, plugin network adapter.
The shutdown and monitoring interface adapter for an Ethernet connection is called an SNMP adapter (Simple Network Management Protocol), which allows the power backup UPS to have an IP address on a user’s network, such that it can be seen by the rest of the network devices.
Using the freely downloadable software, from the AROS RIELLO UPS website: www.riello-ups.com, the UPS user can interface his network and power backup UPS, so that when the power fails, the UPS will initiate a controlled shutdown, of all the connected IT network loads, using the user’s network, as a communication platform.
Upon a power failure after a preset and easily adjustable time, this shutdown and monitoring software, then switches off the connected loads automatically, according to your preferred user settings, and thus prevents any data crash and hardware damages from happening, due to a sudden power supply loss when the backup battery goes flat.
The controlled shutdown can also be used as a backup system in the event your backup emergency power diesel generator, does not start or possibly there are power circuits that trip during the startup process, due to sudden inrush current being demanded from the diesel generator sets built-in alternator.
The controlled system shut down after a power failure will be initiated by the UPS using its RS232 Ethernet interface card. The software essentially automates the UPS backup process, so the user does not need to be present 24/7 or intervene in any way when the power goes out.
This system will also help keep a certain amount of reserve backup power available from the battery as it will not allow the battery to get completely flat but rather only allow partial battery power discharge and keep reserve battery power to back up the UPS inverter, for later use.
The freely downloadable shutdown and monitoring backup power UPS software can also be used to send SMSs or emails, via the user’s network, to notify the user remotely of any incident, including mains power failure, UPS overload, UPS fault and many other condition alerts.