The OLR 84 S protection relay from NewElec, when mounted on a motor circuit, eliminates impact torque conditions which can result in broken chains, damaged screw conveyors, broken couplings and even damaged gearboxes.
The OLR 84 S relay has two settings. The first designates the total start time for the given motor in seconds through a range up to 50 s while the second designates the load trip threshold. The latter setting is percentage calibrated from 30 to 120% of the selected CT ratio XXX:1. It is necessary for the user to select an appropriate ring CT that will cover the expected trip threshold current. A general rule is that if the motor load maximum current is x A, the user must select a current transformer where 3x A is about mid-scale. The reason for this is that a stall or jam condition usually manifests itself at about three times motor full load when the motor develops an output torque in the region of 2,5 to 3 times its normal rated torque. This output torque will then be amplified through a factor dependent on the gearbox ratio.
The OLR 84 S permits the starting current for the motor start but will cause a trip in 100 ms if the motor load suddenly exceeds the upper trip threshold where the motor enters a stall condition after the starting sequence. In doing so, it will interrupt the supply to the motor by means of the main holding contactor and prevent mechanical fractures in the production process.
Read more...Why utilities must prioritise maintenance of SA’s remote data Schneider Electric South Africa
Electrical Power & Protection
The story of power generation is more than meets the eye. Beyond energy distribution and the infrastructure are invisible, point of presence data centres located the remotest parts of our country that play a fundamental role in keeping systems running
Read more...The house that revolutionises substations WEG Africa
Electrical Power & Protection
Traditional substations have major drawbacks in terms of their construction and resilience. One solution is the E-house, a prefabricated, customised and transportable steel structure designed to house a range of electrical and automation equipment.
Read more...Localised inverter-integrated transformer
Electrical Power & Protection
ACTOM, South Africa’s largest manufacturer, repairer and distributor of electromechanical equipment, is launching a breakthrough in renewable energy integration with its localised inverter-integrated transform
Read more...ABB innovation for energy efficiency and sustainability
Electrical Power & Protection
The application of sensor technology to reduce the operational and standby power losses of traditional current and voltage transformers can lead to energy savings of 181 MWh over a 30-year period, the lifetime of a typical switchboard in the African environment.
Read more...UPS systems are key to keeping SA’s automotive industry up and running Schneider Electric South Africa
Electrical Power & Protection
During loadshedding, PLCs and OT systems often fail, not because they are directly tied to the factory’s core manufacturing process, but because they are now an integral part of IT infrastructure. When an IT system shuts down, the impact is far more complex than simply restarting machinery.
Read more...ACTOM advances energy infrastructure
Electrical Power & Protection
At this critical juncture where South Africa is poised to modernise its power infrastructure, ACTOM’s Engineering Projects and Contracts (EPC) Division showcased its capabilities for the first time at Enlit Africa 2025.
Read more...Advanced contactor solution to revolutionise motor management Schneider Electric South Africa
Electrical Power & Protection
Schneider Electric South Africa has launched the TeSys Deca Advanced, an advanced contactor solution designed to revolutionise motor management with unparalleled efficiency, reliability, simplicity and sustainability.
Read more...Steaming ahead with boiler skills development
Electrical Power & Protection
As an expert in steam and boiler operations and maintenance, AES is very focused on safety, quality, technology advancement and the development of human capital. The company invests heavily in training and the promotion of talented people on an equal opportunity basis into the industrial operations environment.
While every effort has been made to ensure the accuracy of the information contained herein, the publisher and its agents cannot be held responsible for any errors contained, or any loss incurred as a result. Articles published do not necessarily reflect the views of the publishers. The editor reserves the right to alter or cut copy. Articles submitted are deemed to have been cleared for publication. Advertisements and company contact details are published as provided by the advertiser. Technews Publishing (Pty) Ltd cannot be held responsible for the accuracy or veracity of supplied material.
printer friendly version