General-purpose LV motor protection relays
November 2001
Motion Control & Drives
NewElec's locally designed and manufactured KA range of relays offer economical solutions for general-purpose LV motor protection. The KA relays are compact in size providing protection against overload, unbalance/single phasing, phase rotation, phase symmetry, overvoltage, undervoltage and minimum loads. Their over/under voltage and phase rotation features make the KA relays particularly suited for low voltage pump motor protection.
The integral current transformers allow for direct connection into the main circuit of the protected motor for currents up to 25 A. Above 25 A, external current transformers are used. The overcurrent level dial setting covers 10% to 100% of the specified current transformer.
Both cyclic and sustained overloads are protected by pre-loading with thermal memory utilising accurate hot and cold thermal curve characteristics to IEC 255-8. In the event of an overload trip, the entire thermal capacity of the motor has been activated. If auto reset has been selected, the motor overload LED will flash until the thermal capacity has integrated to 33%.
Phase unbalance protection is provided independent of motor load. In the event of the three line currents becoming unbalanced by more than 35%, a 5 s trip delay is initiated. Incorrect phase rotation will result in the corresponding LED switching on, while the 'relay healthy' LED will switch off and de-energise the main trip relay. In the event of the phase voltages becoming unbalanced by more than 10%, a 10 s trip delay is initiated, after which, the phase rotation LED is pulsed at 1s intervals. The 'relay healthy' LED will then switch off and trip the main relay.
If the main circuit voltage becomes greater than 120%, or less than 80% rated supply, a 10 s trip delay is initiated. During a minimum load condition, the main trip relay de-energises after 10 s, and if during this period the load current increases above minimum load % MLC dial setting, and drops below this value once more, a new 10 s trip delay period will occur.
NewElec
(012) 327 1729
[email protected]
www.newelec.co.za
Further reading:
Plastics improve machine performance and reliability
igus
Motion Control & Drives
Engineered plastics from German polymer manufacturer, igus continue to revolutionise mechanical systems across various industries worldwide, with a pledge to ‘improve what moves’ by replacing moving steel components with polymer equivalents.
Read more...
Integrated solutions power the future of mining
ABB South Africa
Motion Control & Drives
ABB has a diverse array of solutions that cater to multiple industry sectors, and especially mining. Mining companies across South Africa are embracing automation and control technologies.
Read more...
Keeping the ball rolling
Bearing Man Group t/a BMG
Motion Control & Drives
BMG’s Fluid Technology team has recently completed the design, supply and commissioning of an advanced lubrication system for a main bearing on a ball mill, which has been developed to optimise productivity and minimise maintenance requirements and downtime.
Read more...
Get your bearings right
Bearing Man Group t/a BMG
Motion Control & Drives
BMG’s Bearings Division offers a comprehensive range of bearings, which comprise ball, roller, and linear bearings ranging in size from miniature to extremely large units.
Read more...
SEW-EURODRIVE prioritises ecology and economy
SEW-EURODRIVE
Motion Control & Drives
Committed to environmental sustainability principles, SEW-EURODRIVE has developed the ECO2 design to offer drives with uncoated aluminium, with no compromise in their performance and durability.
Read more...
A year of innovation and milestones for ISO-Reliability Partners
Motion Control & Drives
For ISO-Reliability Partners 2024 was a transformative year marked by innovation, collaboration and a steadfast commitment to advancing industrial reliability. Guided by CEO, Craig FitzGerald, the company has introduced cutting-edge technologies, expanded its product portfolio and strengthened its reputation as a leader in lubrication, filtration and tribology.
Read more...
The impact of gearless mill drive technology on CO2 emissions
ABB South Africa
Motion Control & Drives
ABB has released an in-depth white paper detailing the vital role that gearless grinding technologies can play in driving productivity in mining while simultaneously reducing their carbon footprint.
Read more...
Global geared motors market
Motion Control & Drives
The global geared motors market experienced significant growth from 2021 to 2023, driven by market recovery following the pandemic in 2020, and high backlog levels in 2022.
Read more...
Innovative new products from maxon
DNH Tradeserve t/a DNH Technologies
Motion Control & Drives
A series of innovative new products has been launched by maxon. These include a drive with a diameter of just 16 millimetres, a controller that can be easily integrated into even the tightest of spaces, and a robust and reliable robotic actuator.
Read more...
Effective dust control
Motion Control & Drives
BLT WORLD, in conjunction with the global ScrapeTec team, plays an important role throughout Africa by assisting companies, during conveyor handling, to manage dust emission and material spillage effectively.
Read more...
printer friendly version