In a motor circuit a short circuit condition occurs when the insulation between the phase conductors fails and the load current level exceeds the normal locked rotor current level that the motor would draw during startup. The fault level of the motor feeder supply determines the current level during a short circuit and can be as high as 15 to 50 times the motor’s full load current value.
A short circuit fault is a system level fault. This means that it compromises the stability of the entire network, resulting in total power loss to healthy drives and shutting down an entire process. The MCCB is a maintenance specific item that can appear to be functional even when it is not. This can result in a catastrophic failure on the next fault clearance.
NewElec’s MA motor protection relay is able to protect against thermal overloads, locked rotor and running stall or jam. The MA also protects against short circuit faults and automatically takes care of trip co-ordination so that the main contactor is not used to disrupt high energy faults.
Additional features of the MA include real-time and date stamping recorded by the relay for the last four trips; a recording utility of actual RMS loads; thermal conditioning; mains phase voltage; line voltage; and status of digital inputs and output contacts. The user also has the option of expanding the unit for fieldbus communications via Profibus DP, Modbus RTU and Canbus protocols.
Rail electrification and EV solutions for integrated transport systems
Electrical Power & Protection
A comprehensive range of solutions for rail electrification and electric vehicles is available from leading technology provider ABB, contributing significantly to integrated and sustainable transport systems.
Read more...PPS delivers containerised distribution board for Western Cape hybrid power project
Electrical Power & Protection
South African electrical enclosure specialist Power Process Systems has successfully completed the design, fabrication and commissioning of a 4000 A containerised distribution board for a wind/PV solar hybrid renewable energy project on a site in the Western Cape.
Read more...The choice of a thermal carrier is critical for optimal processing
Electrical Power & Protection
Historically steam, fuelled by coal, has been the most prevalent thermal carrier in South African industry. However, times are changing, with the manufacturing and processing sector needing to review the energy reticulation systems and thermal carriers currently in use.
Read more...ABB’s blueprint for a net zero future
Electrical Power & Protection
ABB’s Mission to Zero is a strategic initiative aimed at achieving a sustainable future characterised by zero emissions, zero accidents and zero waste.
Read more...General-purpose 350 W AC-DC power supply
Electrical Power & Protection
The TDK-Lambda GUS350 series of compact single-output general-purpose power supplies addresses the need for an economically priced product while maintaining reliability and quality.
Read more...Ground-breaking battery tester Comtest
Electrical Power & Protection
Midtronics offers the proven MVT handheld battery tester. This revolutionary tool, powered by MDX-AI, is set to redefine the standards of battery diagnostics and testing in the automotive industry.
Read more...Energy audits pave the pathway to sustainability and savings Schneider Electric South Africa
Electrical Power & Protection
Energy audits serve as essential tools for businesses looking to reduce costs and meet environmental targets. By analysing energy consumption across systems such as lighting, HVAC, ICT and water infrastructure, audits identify inefficiencies and quantify carbon footprints, enabling data-driven decisions for operational and financial optimisation.
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