Softer water with simpler starters
22 January 2008
Assembling even one reversing starter from conventional components is time consuming and tedious, so having to assemble 150 of them is a far from pleasant prospect. That's why German panel builder Hell chose Moeller Electric xStart products, which use tool-less plug connectors for the starters in the control panels it recently supplied to Energie Wasser Niederrhein, a major utility company.
To comply with a German law designed to reduce detergent usage and minimise the damage caused to heaters and similar equipment by hard water, Energie Wasser Niederrhein has to soften water before delivering it to consumers. For this purpose, the company has recently installed a water softening plant which incorporates two 15-tonne reactors, with a total capacity of 1,000 cubic metres of treated water per hour.
Panel builder Hell was successful in securing the contract to supply all of the electrical equipment for the new plant, which included switchboards, process control and automation systems. For this important project, which required no fewer than 30 switchboards and control panels, the company standardised exclusively on equipment from Moeller Electric.
Among the products used were NZM4 circuit breakers with ratings up to 800A and robust RMQ-Titan command signalling devices. The design of the motor control panels presented a particular challenge, however, as the plant incorporates 150 slide and ball valves, each of which requires a reversing starter.
While conventional starters assembled from individual components could have been used, the amount of time required to mount and wire them would have greatly increased the costs and, with so many starters involved, the risk of wiring errors would have been substantial. The engineers at Hell decided, therefore, to use xStart MSC-R starters.
These versatile reversing starters, which use PKZM motor protective circuit breakers to provide fully co-ordinated overload and short-circuit protection, can be completely assembled, using a pluggable connector to make all of the key power connections, prior to installation. No tools are required, and the connector eliminates almost all of the conventional wiring, saving time and making wiring errors virtually impossible.
A further benefit is that, for commissioning and testing purposes, the starter can be completely and positively isolated simply by removing the connector module. xStart MSC-R reversing starters also feature an internally fitted mechanical interlock. Using this does not increase the overall dimensions of the starter and it therefore allows best use to be made of costly panel space.
In this project, Hell adopted a prefabricated busbar system to supply power to the starters. The starters simply snap into place on the busbars, which makes installation easy and, should it ever become necessary to replace a starter, this is a fast and straightforward task.
"We estimate that using the Moeller Electric xStart reversing starters in this project reduced the assembly and wiring time by as much as 80%," said Volker Krebs-Rahmlow, a manager of Hell. "We also saved time on testing, as there were, of course, no wiring errors. And we're not the only ones impressed by Moeller Electric xStart MSC starters - they have now been specified as a standard for all motor starters supplied in future to our customer, Energie Wasser Niederrhein."
Moeller Electric MSC motor starters, as supplied by Hell to Energie Wasser Niederrhein, are available in DOL and reversing versions with ratings up to 16A. Moeller Electric also offers many other ranges of motor starters, including network-ready types, and versions based on vacuum contactors.
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