Water & Wastewater Treatment Magazine
Issue link: https://fhpublishing.uberflip.com/i/1131895
10 | JULY 2019 | WWT | www.wwtonline.co.uk The Talk: Opinion SPONSORED BY CLAYTON MEAD, UK WATER INDUSTRY MANAGER, DRIVES ABB 50 years old, more powerful than ever Today's variable speed drives are virtually unrecognisable from their early versions, and are packed with intelligent technology that opens up opportunities V ariable speed drives (VSDs) celebrate their 50th anniversary this year. Their role back then, as today, is to regulate the speed of an electric motor, driving a pump, fan or compressor (among other applications). The aim: to control the flow rate without the use of mechanical dampers, guide vanes or valves. The side-effect of this productivity-enhancing technique is that the VSD also cuts energy consumption. Adjusting the motor speed, depending on demand, means that the pump or fan no longer runs flat out. It's all down to the famous affinity laws, which say that by reducing the motor's speed, the power reduces by the cube of the speed change. Reducing the speed of a pump or fan with a VSD will o†en save between 20 to 60 per cent of the energy. In reality, very small speed changes can yield large energy savings. Globally, ABB estimates that around one- quarter of all its drives are used on pumps. This equates to an energy saving in excess of 11 billion kWh per year. But it is not just energy saving from which the water industry can benefit. VSDs can help with the health and safety, resilience and maintenance needs of a water plant. Digitally speaking, a VSD was well ahead of its time. When ABB harnessed the motor control concept, direct torque control back in 1996, not only was its motor model the first example of a digital twin, but it brought an unimaginable precision in motor control. Since then the digital technology has continued to flow. A VSD features bespoke functions including inbuilt pump cleaning that ensures clog-free operation, ability to boost pipeline pressure before pump shut down to save energy, protecting pipe networks from pressure peaks when starting pumps and reducing risk of water hammer and pressure transients which can damage pipes. A little known fact is that a VSD has in-built technology that can replace many of the components found within a typical motor control panel. For instance, thermostats used for controlling cabinet fans to save standby losses, timer relays, contactors, door-mounted HMIs, moving iron meter indicating amps or volts and a mini PLC for decision making or for controlling the system: these can all be removed as they are built-in to the VSD. But perhaps the epitome of advances in VSD technology is reflected in the keypad. Here the user no longer needs a manual to decipher the random letters and number patterns that made up parameter settings. Now the screens display everything in plain English (or several other languages). For instance, today's VSD keypad offers 21 variables, displayed via graphs, charts and meter readings that speak the language of any application. There is no need for any analogue meters as the keypad has a view that looks like an analogue moving iron meter, scaled and labelled in the correct customer units. The keypad negates the need for cabinet furniture such as start/stop buttons, as these can be programmed into the keypad. Costs are saved as the sheet metal worker no longer needs to cut holes for an external HMI. Text editing means that if you are pumping water, for instance, you don't need to read the motor's speed in rpm but rather the actual flow rate in litres per second with scaling factors. Flowrox has made more than 40 000 global deliveries to chemical, waste water treatment and oil applications. Flowrox Packaged Pumping Systems TM ● Engineered pump units equipped with simple site connections ● Flexible & compact mounted modular design ● Accurate and repeatable flow ● Reduced maintenance time and cost Just plug & play! ASK FOR MORE: 880-356-9797 / sales-us@flowrox.com S I N C E 1 9 7 7 F L O W R O X . C O M Follow us: