Adrian van Wyk, Managing Director at Referro Systems, says there is no need to reinvent motor control coordination when it’s integrated into the system. He cautions against the risks of using untested components in motor control combinations.
It is essential to use tested combinations in motor control circuits, to ensure safety.
“A motor control circuit is made up of basic interconnected components that achieve the required performance. The components will vary in size depending on the motor’s power, but the operational principles stay the same. It is possible to design a high-performance motor control combination using a few basic components.
“However, combining type 1 with type 2 motor control elements without testing can have serious negative effects. If an untested combination is used, there is a high risk of causing damage in the motor control centre and there is also a risk of causing an arc flash, which could cause further damage and serious injury to plant personnel.
“Testing coordinated combinations is expensive, but it’s essential to use tested combinations to reduce risk, meet international standards and ensure safe and efficient motor control combinations.
“A safer and more pragmatic approach is to use Rockwell Automation’s Global short-circuit current ratings (SCCR) tool, which provides coordinated high-fault branch circuit solutions for motor starters, soft-starters, and variable speed drives. The one-line bill of materials provides coordinated high-fault SCCR ratings for all power devices used in the circuit, and saves customers the time and effort of determining these ratings. The data provided by the Global SCCR tool is based on compliance to IEC and UL standards, pinpointing combinations that have been tested with coordination tables from 0.5 kW to 600 kW at various voltages and fault levels. These also include South Africa’s unique yet very common, mining motor control operational voltage of 525 V/ 550 V, which is not a global test voltage.
“There are specific products and variations of products that work together safely in a motor control circuit; these have been tested by Rockwell Automation and are available to the public.
“The SCCR website is the easy way to select safe, already tested combinations,” van Wyk says. “This allows companies to build their motor control combinations using complimentary elements that have been tested and are compliant with the regulations. Using tested combinations, customers are assured of performance levels and safety.”
For more information visit: www.referro.co.za
