NewElec’s MA Series motor protection relays provide protection against underloads or undercurrents, sustained and cyclic overload conditions, and unbalanced current, single phasing and earth leakage.
An underload condition occurs when the load drawn by a motor is below the minimum safe load power factor, resulting in a faulty or abnormal operating condition. It occurs during loss of a driven load. Typical examples are loss of suction on a centrifugal pump; snapping of a V-belt on a pulley driven load; or shearing of the motor shaft or coupling shearing pin.
Underload is detected by measuring the power factor of the motor load being drawn by the motor windings and establishing that it is less than the preset minimum power factor of the process. Should an underload condition be detected, an alarm is generated and after a preset time delay – 1 to 100 seconds is typical – the motor is tripped.
Underload protection should be used whenever the process load, production line or process is critical. A typical example is when an oversized motor is used, resulting in insufficient current differential between a loaded and unloaded motor in the production process. Another example is when a process controlled by DCS or scada uses an auxiliary contact on the contactor via the I/O block. This is used to indicate a run signal and will cause interlocking of other drives downstream to the affected drive, resulting in spillages as a result of the faulty drive not clearing the material through its part in the process.
Quantum battery charges in a quadrillionth of a second with a laser
Electrical Power & Protection
Researchers have created the world’s first miniature, proof-of-concept quantum battery. If the technology can be replicated, it could transform the field of energy storage forever and open up new possibilities for lightweight, remote electrification, experts say.
Read more...Unpacking the technoeconomic case for cleaner power in wastewater plants Schneider Electric South Africa
Electrical Power & Protection
Behind every reliable wastewater plant is an electrical system exposed to the effects of harmonics, voltage distortion and overloaded networks caused by fleets of variable speed drives on pumps and aerators.Together, they steadily drive up maintenance demands and elevate the risk of failure.
Read more...Energy strategy as a competitive advantage for African businesses
Electrical Power & Protection
Energy is no longer simply something that businesses consume. When managed effectively, it becomes a controllable asset that supports resilience and efficiency and sets the foundation for long-term competitiveness.
Read more...World’s fastest 14 bit arbitrary waveform generator Vepac Electronics
Electrical Power & Protection
The ARB Rider AWG-700 from Vepac is the world’s fastest 14 bit arbitrary waveform generator, with a 20 GS/s real-time update rate and 14 bit vertical resolution.
Read more...Transformers for mining house in Botswana ACTOM Electrical Machines
Electrical Power & Protection
LH Marthinusen is completing the manufacture of two 30 MVA transformers for a mining house in Botswana.
Read more...Rethinking power for Africa’s data centres Schneider Electric South Africa
Electrical Power & Protection
Africa’s digital economy is scaling faster than its power systems. If it wants resilient, competitive and sustainable data centres, the starting point must be a grid-to-chip architecture rather than a genset-first mentality.
Read more...The growing decentralisation of power grids
Electrical Power & Protection
The decentralisation of power generation is changing how national grids function. For electrical engineers, several new challenges and opportunities are on the horizon.
Read more...Custom mini substations for Zambian copper mine
Electrical Power & Protection
Recent orders to supply seventeen specially engineered mini substations for an underground copper mine in Zambia reinforces Trafo Power Solution’s track record in delivering customised electrical solutons for challenging environments.
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