Variable speed drives (VSDs) are generally considered as vital contributors to energy efficiency, but they also have features that can reduce the operational disruptions caused by loadshedding.
“Any industrial operation that relies on electric motors will face severe challenges to its continuous workflow when loadshedding strikes,” says Pieter de Villiers, Gqeberha branch manager for Zest WEG. “Much of the disruption is related to the process of starting machinery up again after a power loss, which often must be conducted as a series of sequential actions that an operator must oversee and implement.”
He adds that many motor users are not aware of the usefulness of WEG VSDs in automating and controlling this start-up. WEG VSDs can be programmed to initiate a sequence of actions, so that this does not have to be done manually by the operator. A simple example to illustrate his point is where water is being pumped through pipelines which drain out during loadshedding. In most cases, the pumps cannot simply be started up again at full speed in a dry condition, without the risk of cavitation and other damage.
“In cases like this, the WEG VSD can be programmed to start the pump at a lower speed until the pipeline is full of water, after which it could resume full pumping duties,” he says. “Similarly, it is important for a siren to be sounded on a mining operation before a conveyor system is re-activated after the start of loadshedding, for safety reasons. The WEG VSD can also be programmed to automate the re-start process, and it initiates the siren to warn staff that the conveyor will be running again.”
He highlights that the full range of WEG VSDs have built-in PLC capability, allowing them to be programmed in this way – without the need for PLCs to be added to the system. Another function of VSDs that makes them valuable assets in times of loadshedding is to prevent equipment from tripping out. This can happen when there is too much ‘dead time’ between grid power turning off and a back-up generator kicking in.
“If dead time lasts more than a few seconds, many motor-driven applications can trip out and require a re-start, which can be time consuming and labour intensive. A common way that the VSD stays live during this dead time is through the stored energy in its capacitors, allowing it to then re-accelerate the motor when the generator kicks in,” he explains. “It is also possible to set up the drive to utilise the inertia from the load and therefore power from the motor itself − essentially using the motor briefly as a generator to keep the VSD alive.”
WEG VSDs also play a useful role when energy users want to harness renewable energy sources like solar power. In a hybrid power system where a motor is connected to both the grid and to solar panels, a VSD can utilise the best source to feed the motor. If there is sufficient sunlight, the system will detect the power flowing in from the panels and optimise that power source.
“On the other hand, the VSD will switch to grid power at night or when it is cloudy,” says de Villiers. “This allows motors to be kept running while reducing the cost of energy, and also reducing the user’s carbon footprint.”
Safe handling in all sectors Bearing Man Group T/A BMG
Electrical switching & drive systems & components
BMG is committed to ensuring optimum safety standards in all sectors, and encourages and assists customers to adhere to stringent safety legislation during bulk handling. Tsubaki backstops and cam clutches, which have been developed and manufactured in Japan for high efficiency and optimum safety in high- or low-speed applications, meet the requirements of current legislation.
Read more...Leading the way in low maintenance and reliability to drive port success
Electrical switching & drive systems & components
South Africa’s ports play a pivotal role in the nation’s economy, serving as crucial gateways for international trade and commerce. These ports can elevate their status in global trade by modernising operations with cutting-edge lifting solutions, and drive further economic prosperity for the country.
Read more...Motion control platform with customisable CNC user interface
Electrical switching & drive systems & components
The motion control experts at Aerotech have further expanded their Automation1 motion control platform. The latest version, 2.8, comes with a customisable CNC user interface, and now offers even more flexibility and user-friendliness for CNC users.
Read more...Drive technology for tunnel construction
Electrical switching & drive systems & components
Compact, robust, and reliable - these are the advantages of RUD’s Tecdos drive technology, which is a gamechanger in tunnel construction.
Read more...EtherCAT measurement terminals for vehicle development at Mercedes-Benz Beckhoff Automation
Electrical switching & drive systems & components
At the Mercedes Technology Centre plant in Sindelfingen, Germany, car axles are examined with the highest precision on four test benches, in parallel with road tests and simulations. All data is acquired using PC-based control from Beckhoff.
Read more...Perfect balance for every race Horne Technologies
Editor's Choice Electrical switching & drive systems & components
It goes without saying that success in Formula 1 requires a top driver. However, their chance of achieving a place on the podium depends on the car, which in turn depends on three essential factors: engine, tyres and aerodynamics. To find the optimum balance, the racing teams test models of their bolides in the wind tunnel. At Sauber, the adjustable components are moved on the model and in the test chamber using FAULHABER motors.
Read more...Reshaping the future of air freight with Siemens software Siemens South Africa
Electrical switching & drive systems & components
Aerospace company, Natilus has adopted the Siemens Xcelerator portfolio of industry software. The company is focused on transforming the world’s supply chain with its next-generation blended-wing body aircraft, and through its use of Siemens software it has reduced the development time to build its first prototype aircraft by 50%.
Read more...Electrifying the future Parker Hannifin - Sales Company South Africa
Editor's Choice Electrical switching & drive systems & components
A revolution is underway, transforming the way we power compact construction machines and heavy-duty mobile machinery. This is the electrification of equipment, a movement propelled by the need for environmental sustainability, lower emissions, reduced noise levels, and the pursuit of a cleaner, greener future.
Read more...WEG to debut at Electra Mining Africa WEG Africa
News & events
WEG has maintained a formidable presence on the African continent for over four decades, consistently demonstrating its industry-leading capabilities at Electra Mining Africa under the Zest WEG brand. This year, a rebranded WEG is poised to make a powerful debut with a renewed focus on innovation and sustainability.
Read more...High-performance motion control for teabag packaging machine Beckhoff Automation
Electrical switching & drive systems & components
Teepak relies on PC-based control and drive technology from Beckhoff to set new benchmarks for speed and precision in its teabag packaging machines.
printer friendly version